Ghada World — Science Quizzes EncyclopediaGhada World — Science Quizzes Encyclopedia
Ghada World — A trusted Q&A encyclopedia · 23,105 questions · Part 1 of 47
Q1: Order these chemists by when they lived, from earliest to latest:
Answer: Jabir ibn Hayyan then Abu Bakr al-Razi then Antoine Lavoisier then Dmitri Mendeleev
💡 Jabir ibn Hayyan is associated with the 8th century CE, al-Razi with the 9th and 10th centuries, Lavoisier with the 18th century, and Mendeleev with the 19th century.
Q2: Salt water boils at a slightly higher temperature than pure water.
Answer: True ✔
💡 Dissolved salt raises the boiling point of water slightly, so salt water needs a little more than 100 degrees Celsius to boil.
Q3: Marie Curie is one of the most famous scientists to study radioactivity, and with her husband Pierre she discovered the elements polonium and radium.
Answer: True ✔
💡 Marie Curie studied the radiation given off by some elements and coined the term "radioactivity," and with her husband Pierre she discovered polonium and radium in 1898.
Q4: Marie Curie was the first person to win the Nobel Prize twice. In which two fields did she win?
Answer: Physics and chemistry
💡 Marie Curie won the Nobel Prize in Physics in 1903 with her husband Pierre and Henri Becquerel, then the Nobel Prize in Chemistry in 1911.
Q5: Which Muslim scientist combined medicine and chemistry and is credited with classifying substances as mineral, plant and animal?
Answer: Abu Bakr al-Razi
💡 Abu Bakr al-Razi was a physician and chemist who lived in the 9th and 10th centuries CE; he is credited with classifying substances and describing lab tools and processes such as distillation.
Q6: Why are people warned against mixing household bleach with other cleaners, such as those containing ammonia?
Answer: Because the mixture releases dangerous toxic gases
💡 Mixing bleach with ammonia or some acidic cleaners releases toxic gases that harm the lungs, so each cleaner should be used alone with good ventilation.
Q7: How does soap help remove greasy stains with water?
Answer: Its molecules have one end attracted to water and one end attracted to grease, so it surrounds the grease and carries it away with the water
💡 Soap surrounds droplets of grease with its grease-loving ends, while its water-loving ends stay on the outside, so the water washes them away during rinsing.
Q8: What gas bubbles up when baking soda is mixed with vinegar?
Answer: Carbon dioxide
💡 Baking soda is a base and vinegar is an acid, and when they react, carbon dioxide gas is released, making bubbles and foam.
Q9: Which alloy is made mainly of copper and tin?
Answer: Bronze
💡 Bronze is an alloy of copper and tin, and it was so important that a whole era of human history was named "the Bronze Age."
Q10: What do we call water vapor turning into drops of water on the surface of a cold glass?
Answer: Condensation
💡 Water vapor in the air cools when it touches the cold surface of the glass and turns into liquid; this is condensation.
Q11: Order these substances by pH, from most acidic to most basic:
Answer: Lemon juice then Coffee then Pure water then Baking soda solution then Household bleach
💡 Lemon juice is about 2, coffee about 5, pure water 7, baking soda solution about 9, and household bleach about 12 or higher.
Q12: Match each state of matter with its description:
Answer: Solid ↔ Has a fixed shape and a fixed volume, Liquid ↔ Has a fixed volume and takes the shape of its container, Gas ↔ Has no fixed shape or volume and spreads out to fill the space
💡 The particles of a solid are close together and held tightly, the particles of a liquid slide over one another, and the particles of a gas are far apart and move freely.
Q13: Which acid gives vinegar its sharp taste?
Answer: Acetic acid
💡 Vinegar contains a small amount of diluted acetic acid, which is responsible for its sour taste and distinctive smell.
Q14: What is usually produced when an acid reacts with a base?
Answer: A salt and water
💡 This reaction is called neutralization: the acid and the base cancel each other's effects and produce a salt and water.
Q15: What happens to the color of blue litmus paper when it is dipped in an acidic solution?
Answer: It turns red
💡 Litmus paper is a simple indicator: acid turns blue paper red, and a base turns red paper blue.
Q16: The higher a solution's pH is above 7, the more acidic it is.
Answer: False ✖
💡 Numbers above 7 mean the solution is basic, and the higher the number, the more basic it is, while acidity increases as the number goes lower below 7.
Q17: Which number on the pH scale indicates a neutral solution, like pure water?
Answer: 7
💡 The pH scale usually runs from 0 to 14; 7 is neutral, anything below it is acidic, and anything above it is basic.
Q18: The law of conservation of mass, made famous by the French scientist Lavoisier, states that...
Answer: The mass of substances before a chemical reaction equals their mass after it
💡 In a chemical reaction, atoms are rearranged and are neither destroyed nor created, so the total mass stays the same if the gases produced are also counted.
Q19: What two gases are produced when water is split by electricity?
Answer: Hydrogen and oxygen
💡 Water is a compound of hydrogen and oxygen, and an electric current breaks it down into them, with twice as much hydrogen produced by volume as oxygen.
Q20: Why should you never put out burning oil in a frying pan with water?
Answer: Because the water suddenly turns to steam and throws the burning oil, spreading the fire
💡 Water is heavier than oil, so it sinks below it and boils off suddenly, throwing the burning oil around and making the fire bigger; the right thing to do is turn off the heat and cover the pan with its lid if it can be done safely.
Q21: How does a carbon dioxide fire extinguisher put out a fire?
Answer: It covers the fire with a gas that does not burn, keeping oxygen away
💡 Carbon dioxide is a gas that does not burn and is heavier than air, so it covers the fire, keeps oxygen away from it and also cools it, so it goes out.
Q22: Choose the three ingredients any fire needs to burn (the fire triangle):
Answer: Fuel, Oxygen, Heat
💡 Burning needs fuel to burn, oxygen and enough heat, and if we remove any side of the triangle, the fire goes out.
Q23: Choose all the ways to protect iron from rusting:
Answer: Painting it, Covering it with a layer of oil or grease, Coating it with a layer of zinc (galvanizing)
💡 Paint, oil and zinc keep iron away from air and moisture, while wetness and salt water speed up rusting.
Q24: What two substances does iron need in order to rust?
Answer: Oxygen and water
💡 Rust is the oxidation of iron: iron combines with oxygen in the air in the presence of water or moisture, forming a brittle brown layer.
Q25: What is the main sign that a chemical change has happened?
Answer: A new substance with different properties forms
💡 A chemical change produces a new substance; its signs include a gas being given off, a change in color, heat and light being released, or a precipitate forming.
Q26: Choose all the physical changes from the following:
Answer: Water evaporating, Breaking a glass cup, Wax melting
💡 In a physical change, a substance's shape or state changes but it stays the same substance, while rusting and cooking an egg are chemical changes in which new substances form.
Q27: Which of the following is a chemical change?
Answer: Burning paper
💡 Burning turns paper into new substances such as ash, gases and smoke that cannot be turned back into paper, while tearing, folding and melting are physical changes.
Q28: Steel is a strong alloy used to make bridges and cars; its main ingredient is iron with a small amount of...
Answer: Carbon
💡 An alloy is a mixture of a metal with one or more other elements, and steel is iron with a little carbon added, making it stronger and harder than iron alone.
Q29: What is the method of getting pure water from salt water by evaporating it and then condensing the vapor?
Answer: Distillation
💡 In distillation, the water evaporates and the salt stays in the container, then the vapor is cooled so it condenses into pure water collected in another container.
Q30: Sugar dissolves faster in hot water than in cold water.
Answer: True ✔
💡 Heat makes the water particles move faster, so they hit the sugar grains and separate them more quickly, which is why sugar dissolves quickly in hot tea.
Q31: Oil dissolves in water and forms a uniform solution with it.
Answer: False ✖
💡 Oil does not dissolve in water; it floats on top in a separate layer because it is less dense, so together they form a non-uniform mixture.
Q32: Water is nicknamed "the universal solvent" because it dissolves a very large number of substances.
Answer: True ✔
💡 Water dissolves many substances, such as salt, sugar and some gases, which is why river and sea water carries dissolved salts and minerals.
Q33: When sugar is dissolved in water, what is the sugar called in this solution?
Answer: The solute
💡 A solution is made of a solute (the substance that dissolves, like sugar) and a solvent (the substance that dissolves it, like water).
Q34: Which of the following is a mixture and not a compound?
Answer: Air
💡 Air is a mixture of gases such as nitrogen, oxygen and others that have not combined chemically, while water, salt and carbon dioxide are compounds with fixed proportions.
Q35: Sodium is a highly reactive metal and chlorine is a toxic gas, so how can table salt, made of the two, be safe to eat?
Answer: Because the resulting compound has new properties completely different from those of its elements
💡 When elements combine chemically, a new substance forms with different properties, so table salt is white crystals that are safe in moderation, even though sodium and chlorine are dangerous on their own.
Q36: Match each chemical formula with the name of the substance:
Answer: H2O ↔ Water, CO2 ↔ Carbon dioxide, CH4 ↔ Methane gas, O2 ↔ Oxygen gas
💡 H2O is two hydrogen atoms and one oxygen atom, CO2 is one carbon atom and two oxygen atoms, CH4 is one carbon atom and four hydrogen atoms, and O2 is a molecule of two oxygen atoms.
Q37: Why does gold stay shiny for hundreds of years and not rust?
Answer: Because it is a metal that barely reacts with oxygen and water
💡 Gold is one of the least reactive metals; it does not combine with oxygen in the air or with water, which is why very old gold jewelry has been found still shining.
Q38: Shiny diamond and pencil graphite are very different materials, but they are made of the same element. Which one?
Answer: Carbon
💡 Diamond and graphite are both pure carbon; the difference between them is how the atoms are arranged, and pencil "lead" contains no lead at all.
Q39: Which of these metals is a liquid at normal room temperature?
Answer: Mercury
💡 Mercury is a silvery metal that is liquid at room temperature; it was used in old thermometers, and its vapors are toxic, so it must not be touched or inhaled.
Q40: Choose all the common properties of metals:
Answer: Good conduction of electricity and heat, A distinctive shine, Can be hammered and drawn into wires
💡 Metals such as iron, copper and aluminum are shiny, good conductors of electricity and heat, and can be hammered into sheets and drawn into wires, while brittleness and poor conduction are properties of solid nonmetals.
Q41: Noble gases react easily with most other elements.
Answer: False ✖
💡 Noble gases are nearly inert and rarely react with others, which is why argon, for example, is used inside some light bulbs to protect the filament.
Q42: Choose all the noble gases from the following:
Answer: Neon, Argon, Krypton
💡 Neon, argon and krypton are noble gases in the last column of the periodic table, while oxygen and chlorine are chemically reactive gases.
Q43: Order these elements by atomic number, from smallest to largest:
Answer: Hydrogen then Helium then Carbon then Oxygen then Sodium
💡 The atomic numbers are: hydrogen 1, helium 2, carbon 6, oxygen 8 and sodium 11, and this is the order in which elements are arranged in the modern periodic table.
Q44: What are the vertical columns of the periodic table called?
Answer: Groups
💡 The vertical columns are called groups (families), and the elements in one group have similar properties, while the horizontal rows are called periods.
Q45: What did Mendeleev do in his table that later proved his genius?
Answer: He left gaps for undiscovered elements and predicted their properties
💡 Mendeleev left empty spaces and predicted the properties of elements that were not yet known, and they were later discovered, such as gallium and germanium, with properties very close to what he predicted.
Q46: Which Russian scientist published a table in 1869 arranging the known elements, which became the basis of the periodic table?
Answer: Dmitri Mendeleev
💡 Mendeleev arranged the elements in a table where similar properties repeat regularly, and his table is considered the basis of the periodic table we study today.
Q47: Select everything that is a chemical element and not a compound:
Answer: Copper, Oxygen, Carbon
💡 An element is a pure substance made of one type of atom, like copper, oxygen and carbon, while water and sugar are compounds of elements joined chemically.
Q48: Match each chemical symbol with the element it stands for:
Answer: Au ↔ Gold, Ag ↔ Silver, Cu ↔ Copper, Cl ↔ Chlorine
💡 Au comes from the Latin name for gold, "aurum," Ag from the name for silver, "argentum," Cu from the name for copper, "cuprum," and Cl is short for chlorine.
Q49: What gas are floating balloons filled with today because it is lighter than air and does not burn?
Answer: Helium
💡 Helium is lighter than air, so it lifts the balloon, and it is an inert gas that does not burn, unlike hydrogen, which catches fire easily.
Q50: What is the lightest of all the chemical elements?
Answer: Hydrogen
💡 Hydrogen is the lightest and simplest element: its ordinary atom has only one proton and one electron, and its atomic number is 1.
Q51: Which element has the chemical symbol N?
Answer: Nitrogen
💡 N is the symbol for nitrogen, while sodium's symbol is Na, nickel's is Ni and neon's is Ne.
Q52: What is the chemical symbol for the element iron?
Answer: Fe
💡 Iron's symbol Fe comes from its Latin name "ferrum," which is why it does not look like its English or Arabic name.
Q53: What is the chemical symbol for the element sodium?
Answer: Na
💡 Sodium's symbol Na comes from its Latin name "natrium," while S is the symbol for sulfur.
Q54: The atom is the smallest thing in the universe and cannot be made of smaller parts.
Answer: False ✖
💡 The atom is made of smaller particles: protons and neutrons in the nucleus, and electrons moving around it.
Q55: The electron carries a negative charge, and its mass is much smaller than the proton's mass.
Answer: True ✔
💡 A proton's mass is about 1,800 times an electron's, which is why the mass of electrons is usually ignored when calculating an atom's mass.
Q56: Where is most of an atom's mass concentrated?
Answer: In the nucleus
💡 Protons and neutrons are much heavier than electrons, so most of an atom's mass is concentrated in its very small nucleus.
Q57: Why is an ordinary atom electrically neutral?
Answer: Because it has as many protons as electrons
💡 A proton's positive charge is equal in size to an electron's negative charge, so if their numbers are equal, the charges balance and the atom is neutral.
Q58: What determines the type of element, making an atom a carbon atom or an oxygen atom, for example?
Answer: The number of protons in the nucleus
💡 The number of protons is the atomic number, the element's ID card: every atom with 6 protons is carbon, and every atom with 8 protons is oxygen.
Q59: Where are the electrons in an atom?
Answer: Around the nucleus in energy levels
💡 Electrons move around the nucleus in energy levels (shells), and they stay bound to it because their negative charge is attracted to the positive protons.
Q60: Which particle inside the nucleus of an atom carries a positive charge?
Answer: The proton
💡 The nucleus of an atom is made of positively charged protons and neutral neutrons, while the negative electrons move around the nucleus.
Q61: Match each simple machine with an example of it:
Answer: Lever ↔ A seesaw in the park, Pulley ↔ A construction crane that lifts loads with ropes, Inclined plane ↔ A wheelchair ramp, Wedge ↔ An ax head
💡 A seesaw is a lever with a fulcrum in the middle, a pulley is a wheel with a rope running over it, a ramp is an inclined plane, and an ax head is a wedge that splits wood.
Q62: Match each scientist with his scientific contribution:
Answer: Alessandro Volta ↔ Inventing the first electric battery, Archimedes ↔ The principle of buoyancy in liquids, Michael Faraday ↔ Electromagnetic induction, Albert Einstein ↔ The theory of relativity
💡 Volta made the first electric battery in 1800 and the volt is named after him, Archimedes discovered the principle of buoyancy, Faraday discovered how to generate electricity from a moving magnet, and Einstein developed the theory of relativity.
Q63: Match each unit of measurement with what it measures:
Answer: Volt ↔ Electrical voltage, Ampere ↔ Electric current, Ohm ↔ Electrical resistance, Watt ↔ Power
💡 The volt is for voltage, the ampere for current and the ohm for resistance, while the watt measures power, the amount of energy used or produced each second.
Q64: Order the energy changes in a hydroelectric power plant at a dam:
Answer: Potential energy of the water stored behind the dam then Kinetic energy of the water rushing down then The turbine and generator spinning then Electrical energy flowing through the wires
💡 The high water has potential energy, which turns into kinetic energy as it rushes down, turning the turbine connected to the generator, which turns it into electricity.
Q65: Order these scientists by when they lived, from earliest to latest:
Answer: Archimedes then Al-Hasan Ibn al-Haytham then Isaac Newton then Michael Faraday then Albert Einstein
💡 Archimedes lived in the 3rd century BCE, Ibn al-Haytham in the 10th and 11th centuries, Newton in the 17th century, Faraday in the 19th century, and Einstein in the 20th century.
Q66: Order these materials by how fast sound travels through them, from fastest to slowest:
Answer: Iron then Water then Air
💡 Sound travels through iron at about 5,000 meters per second, through water at about 1,500, and through air at about 340, so it is usually faster in solids.
Q67: Choose all the changes of state that require gaining heat:
Answer: Melting, Boiling, Sublimation
💡 Melting, boiling and sublimation need heat energy to move the particles apart, while in freezing and condensation the substance loses heat.
Q68: Select all the true statements about mass and weight:
Answer: Mass is measured in kilograms, Weight is a force measured in newtons, Weight changes when the force of gravity changes
💡 Mass is the amount of matter in an object and does not change from place to place, while weight is the force of a planet's pull on the object, so it changes from planet to planet.
Q69: Choose every color of the spectrum that appears when white light is split:
Answer: Red, Green, Violet
💡 The known colors of the spectrum are red, orange, yellow, green, blue, indigo and violet, while black is the absence of light and brown does not appear in the spectrum.
Q70: Choose everything that is a form of energy:
Answer: Kinetic energy, Chemical energy, Sound energy, Light energy
💡 Forms of energy include kinetic, chemical, sound, light, heat, electrical and potential energy, while density is a property of matter, not energy.
Q71: Choose all the examples where friction helps us:
Answer: Walking without our feet slipping, A bike stopping when you squeeze the brakes, Lighting a match by striking it
💡 Friction is a force that resists sliding, so it helps us walk, brake and light things, but it sometimes harms us when it wears down tires and machine parts.
Q72: Choose all the materials that are good conductors of electricity:
Answer: Copper, Aluminum, Iron
💡 Metals are good conductors of electricity, which is why wires are made of them, while plastic and dry wood are insulators used to cover wires and handles.
Q73: The farther apart two objects are, the weaker the gravitational force between them.
Answer: True ✔
💡 According to Newton's law of universal gravitation, gravity weakens as distance increases: if the distance doubles, the force becomes a quarter of what it was.
Q74: Ice floats on water because it is less dense than liquid water.
Answer: True ✔
💡 Water expands when it freezes, so its density decreases; that is why ice floats and lakes freeze from the surface, keeping the fish alive in the water below.
Q75: A steel needle can be magnetized by stroking it with a magnet several times in one direction.
Answer: True ✔
💡 Repeated stroking in one direction lines up the tiny magnetic regions inside the steel in one direction, so the needle becomes a magnet.
Q76: Energy cannot be destroyed or created from nothing; it only changes from one form to another.
Answer: True ✔
💡 This is the law of conservation of energy: the total energy in an isolated system stays constant, and what seems to be lost has usually turned into heat.
Q77: A magnet attracts all metals, including aluminum and copper.
Answer: False ✖
💡 A magnet clearly attracts iron, nickel, cobalt and some of their alloys, but aluminum, copper and gold are not attracted to it.
Q78: When you push a wall with your hand, the wall pushes you back with a force equal in size and opposite in direction.
Answer: True ✔
💡 This is Newton's third law: for every action there is an equal and opposite reaction, and it is also what pushes a rocket upward.
Q79: Pure water boils at 100 degrees Celsius everywhere, even on top of high mountains.
Answer: False ✖
💡 Pure water boils at 100 degrees Celsius at normal air pressure at sea level, but at high altitudes the pressure is lower, so it boils at a lower temperature.
Q80: Light travels faster in water than in a vacuum.
Answer: False ✖
💡 Light is fastest in a vacuum and slows down in water and glass, and this change in speed is what causes light to refract.
Q81: Sound can travel through the empty space between the planets.
Answer: False ✖
💡 Sound is vibrations that need a material medium such as air or water, which is why astronauts outside their spacecraft communicate by radio.
Q82: Why does a shadow form behind an opaque object when light falls on it?
Answer: Because light travels in straight lines and does not bend around the object
💡 Light travels in straight lines, so when an opaque object blocks it, it keeps the rays from reaching the area behind it, forming a shadow.
Q83: Why are small gaps left between the rails of old railroad tracks?
Answer: Because iron expands when the temperature rises
💡 Materials expand with heat and contract with cold, so without these gaps the rails would bend on hot summer days.
Q84: You are trying to lift a heavy rock with a lever resting on a small stone. Which action makes the lifting easier?
Answer: Pushing on the end of the lever far from the fulcrum
💡 The longer the effort arm (the distance between your hands and the fulcrum), the less force is needed to lift the load; this is how a lever works.
Q85: When an ambulance comes toward you and then moves away, how does its siren sound?
Answer: Higher as it approaches, then lower as it moves away
💡 This is the Doppler effect: as the sound source approaches, its waves bunch together, so the frequency rises and it sounds higher; as it moves away, they spread out and the frequency drops.
Q86: About how much does an object with a mass of 1 kilogram weigh on Earth's surface?
Answer: About 9.8 newtons
💡 Weight = mass × gravitational acceleration, and gravitational acceleration on Earth is about 9.8 m/s², so one kilogram weighs about 9.8 newtons.
Q87: Why do we see a red apple as red in sunlight?
Answer: Because it reflects red light and absorbs most of the other colors
💡 The color of an opaque object is the color of the light it reflects into our eyes, while an object that reflects all colors looks white.
Q88: What type of lens is used in a handheld magnifying glass?
Answer: A convex lens
💡 A convex lens is thicker in the middle and brings light rays together, giving an enlarged image of objects close to it.
Q89: Why do astronauts float inside the International Space Station?
Answer: Because they and the station are in continuous free fall around Earth
💡 Gravity at the station's orbit is still about 90% of gravity at Earth's surface, but the station and everyone in it are constantly falling around Earth together, so they feel weightless.
Q90: A 100-watt bulb is left on for 10 hours. How much electrical energy does it use?
Answer: 1 kilowatt-hour
💡 Energy = power × time = 100 watts × 10 hours = 1,000 watt-hours, that is, 1 kilowatt-hour, the unit used to calculate electricity bills.
Q91: Why does a parachutist descend slowly after opening the parachute?
Answer: Because the wide parachute increases air resistance
💡 The parachute pushes against a large amount of air, increasing the air resistance that opposes the fall, so the descent slows down even though gravity is still there.
Q92: You wrapped a wire around an iron nail and connected its ends to a battery, and the nail started attracting pins. What did you make?
Answer: An electromagnet
💡 The current flowing through the coil creates a magnetic field that magnetizes the nail, and most of this magnetism disappears when the current is cut off, which is why it is used in cranes that lift scrap iron.
Q93: What device did Thomas Edison invent in 1877 to record sound and play it back?
Answer: The phonograph
💡 The phonograph was the first device to record sound and play it back, while several inventors before and alongside Edison contributed to the electric light bulb, and he developed a practical, long-lasting version.
Q94: Which field is the inventor Nikola Tesla's name closely linked to?
Answer: Alternating current power systems and motors
💡 Tesla developed the induction motor and the alternating current transmission systems that the world's power grids still rely on today.
Q95: "Dry ice" (solid carbon dioxide) turns directly into a gas without becoming a liquid. What is this change called?
Answer: Sublimation
💡 Sublimation is when a substance changes directly from a solid to a gas; the very cold gas rising from dry ice condenses the water vapor in the air, so it looks like white smoke in shows.
Q96: What is the difference between evaporation and boiling?
Answer: Evaporation happens at the surface of a liquid at various temperatures, while boiling happens throughout the liquid at its boiling point
💡 Wet clothes dry by evaporation without boiling, while in boiling, bubbles of vapor form throughout the whole liquid at a specific temperature.
Q97: When water is heated in a pot, the hot water rises to the top and the cold water sinks to the bottom. What is this way of transferring heat called?
Answer: Convection
💡 In convection, heat moves through the movement of the liquid or gas itself: the hot part is less dense, so it rises, and the cold part takes its place.
Q98: How does the sun's heat reach Earth across space, which is almost empty of matter?
Answer: By radiation
💡 Radiation is the only way of transferring heat that does not need a material medium, which is why the sun's heat crosses space to reach us.
Q99: A metal spoon was placed in a cup of hot tea, and its other end soon got hot. How did the heat travel?
Answer: Conduction
💡 In conduction, heat moves through a solid from one particle to the next without the material itself moving, and metals are good conductors of heat.
Q100: Why does a compass needle point north?
Answer: Because Earth acts like a giant magnet
💡 Earth has a magnetic field as if there were a giant magnet inside it, so the magnetized compass needle lines up with this field and points to magnetic north, near the geographic North Pole.
Q101: What happens when you bring the north pole of a magnet near the north pole of another magnet?
Answer: They repel each other
💡 Like poles repel and unlike poles attract; this is a basic rule of magnetism.
Q102: Three bulbs are connected in series in one circuit, and one of them burns out. What happens to the other two bulbs?
Answer: They go out because the circuit is broken
💡 In a series connection the current has only one path, so if one bulb burns out the path is broken and the current stops in the whole circuit, which is why home appliances are connected in parallel.
Q103: An electric circuit has a 12-volt battery and a resistance of 4 ohms. What is the current flowing through it?
Answer: 3 amperes
💡 By Ohm's law: current = voltage ÷ resistance = 12 ÷ 4 = 3 amperes.
Q104: What determines the pitch of a sound, that is, whether it is high or low?
Answer: The frequency of the vibration (vibrations per second)
💡 The higher the frequency, the higher the pitch of the sound, while the amplitude of the vibration determines its loudness.
Q105: What is an echo?
Answer: Sound reflected off a distant surface that comes back to us
💡 An echo is sound reflected off a surface such as a mountain or a wall, and we hear it separately from the original sound if the surface is far enough away.
Q106: You saw a flash of lightning and then heard the thunder 3 seconds later. About how far away is the lightning?
Answer: About 1 kilometer
💡 Light reaches us almost instantly, while sound travels through air at about 340 meters per second, so in 3 seconds it travels about 1,000 meters.
Q107: What did the scientist Ibn al-Haytham prove in his "Book of Optics" about how we see?
Answer: That light comes from objects to the eye, so we see them
💡 Ibn al-Haytham corrected the old idea that the eye sends out rays, and showed by experiment that light reflects off objects and enters the eye, which is how we see.
Q108: What happens to white sunlight when it passes through a glass prism?
Answer: It splits into the colors of the spectrum
💡 White light is a mixture of colors, and each color bends by a different amount in the prism, so the colors separate; Newton proved this with his prism experiments.
Q109: A ray of light strikes a flat mirror at an angle of incidence of 30 degrees. What is its angle of reflection?
Answer: 30 degrees
💡 The law of reflection: the angle of incidence equals the angle of reflection, and both are measured from the line perpendicular to the mirror's surface.
Q110: When you put a pencil in a glass of water, it looks broken at the water's surface. What is this phenomenon called?
Answer: Refraction of light
💡 Light refracts, or changes direction, when it passes from water to air because its speed is different in each, so the pencil looks broken.
Q111: Which mirrors are used on the sides of cars to give a wider field of view?
Answer: Convex mirrors
💡 A convex mirror reflects an image of a wider area, but it makes things look smaller and farther away than they are, which is why it carries a warning for the driver.
Q112: About how fast does light travel in a vacuum?
Answer: 300,000 kilometers per second
💡 The speed of light in a vacuum is about 300,000 kilometers per second, the highest speed known in the universe.
Q113: What is the main benefit of a single fixed pulley, like the one at the top of a flagpole?
Answer: It changes the direction of the force, so we pull down to raise the load
💡 A single fixed pulley does not reduce the amount of force, but it changes its direction, and pulling down is easier because we can use our body weight.
Q114: Why do we use a ramp (an inclined plane) to lift a heavy barrel onto a truck?
Answer: Because it reduces the force needed in exchange for a longer distance
💡 An inclined plane is a simple machine that reduces the force needed in exchange for the barrel traveling a longer distance; the work done does not decrease, but we use less force than if we lifted the barrel straight up.
Q115: What is the sequence of energy changes in a battery-powered flashlight?
Answer: Chemical → electrical → light and heat
💡 The battery stores chemical energy, which turns into electrical energy in the wires, and then the bulb turns it into light, with some of it turning into heat.
Q116: What is the unit of energy in the International System of Units?
Answer: The joule
💡 The joule is the unit of energy and work, named after the English scientist James Joule, who studied the relationship between heat and work.
Q117: A feather and an iron ball are dropped at the same moment inside a chamber completely emptied of air. What happens?
Answer: They reach the bottom together
💡 Without air resistance, all objects fall with the same acceleration no matter their mass; astronaut David Scott tested this on the moon in 1971 with a hammer and a feather.
Q118: A man weighs 600 newtons on Earth. About how much will he weigh on the surface of the moon?
Answer: 100 newtons
💡 The moon's gravity is about one-sixth of Earth's, so the weight becomes about 600 ÷ 6 = 100 newtons, while his mass stays the same.
Q119: A force of 10 newtons acts on an object with a mass of 2 kilograms. What is its acceleration (ignoring friction)?
Answer: 5 m/s²
💡 By Newton's second law, force = mass × acceleration, so acceleration = 10 ÷ 2 = 5 meters per second squared.
Q120: A bus stopped suddenly and the passengers lurched forward. What explains this?
Answer: Inertia: their bodies tend to keep moving
💡 Newton's first law (the law of inertia) states that an object stays at rest or in motion unless a force acts on it, so the passengers' bodies keep moving even though the bus has stopped.
Q121: Match each planet with what makes it special:
Answer: Mars ↔ Olympus Mons, the largest known volcano in the solar system, Jupiter ↔ The Great Red Spot, a huge storm, Uranus ↔ Spins tilted on its side, Neptune ↔ The fastest known winds among the planets
💡 Olympus Mons on Mars is the largest known volcano, the Red Spot is a huge storm on Jupiter, Uranus has a very tilted axis, and Neptune has the fastest known winds in the solar system.
Q122: Match each space mission with its achievement:
Answer: Sputnik 1 ↔ The first artificial satellite to orbit Earth, Vostok 1 ↔ The first human spaceflight, Apollo 11 ↔ The first human landing on the moon, The Hope Probe ↔ The first Arab mission to Mars
💡 Sputnik 1 was launched in 1957, Vostok 1 carried Yuri Gagarin in 1961, Apollo 11 landed on the moon in 1969, and the UAE's Hope Probe reached Mars orbit in 2021.
Q123: Match each scientist with his achievement in astronomy:
Answer: Copernicus ↔ Put the sun at the center of the solar system, Galileo ↔ Observed Jupiter's largest moons with a telescope, Newton ↔ Formulated the law of universal gravitation, Al-Biruni ↔ Measured Earth's radius from a mountaintop
💡 Copernicus said that Earth revolves around the sun, Galileo observed Jupiter's large moons, Newton explained gravity, and al-Biruni measured Earth's radius by calculating the angle of the horizon from a mountaintop.
Q124: Order the life stages of a star like the sun from beginning to end:
Answer: A nebula of gas and dust then A stable shining star then A red giant then A white dwarf
💡 Stars are born inside nebulae; a star like the sun stays stable for a long time, then swells into a red giant, and ends as a small white dwarf.
Q125: Order these planets from largest to smallest:
Answer: Jupiter then Saturn then Earth then Mars
💡 Jupiter is the largest planet, followed by Saturn, while Earth's diameter is roughly twice that of Mars.
Q126: Order the phases of the moon starting from the new moon:
Answer: New moon then Crescent then First quarter then Full moon
💡 The cycle of the moon's phases starts with the new moon, then the crescent appears, then half the disk is lit at the first quarter, until it becomes a full moon in the middle of the lunar month.
Q127: Choose all the planets that are surrounded by rings:
Answer: Saturn, Uranus, Jupiter
💡 Saturn's rings are the most famous and the easiest to see, but Jupiter, Uranus and Neptune also have faint rings, while the rocky planets have no rings.
Q128: Choose everything that happens during a total solar eclipse:
Answer: The moon completely blocks the sun's disk, The sun's outer halo (the corona) appears, The sky goes dark in broad daylight for a few minutes
💡 In a total solar eclipse, the moon passes between the sun and Earth and blocks the sun's disk, so the sky darkens for a few minutes and the sun's bright halo appears, while the moon turning red happens in a lunar eclipse, not a solar one.
Q129: Choose everything that results from Earth spinning on its axis:
Answer: Day and night following each other, The sun rising in the east and setting in the west
💡 Earth's daily spin on its axis creates day and night and the sun's apparent movement across the sky, while the seasons are caused by the tilt of the axis as Earth orbits the sun, and the phases are caused by the moon's orbit.
Q130: Choose everything that is a star:
Answer: The sun, Canopus (Suhail), Sirius
💡 The sun, Canopus (Suhail) and Sirius are stars that give off their own light, while the moon is a satellite and Mars is a planet, and both reflect sunlight.
Q131: Choose all the planets that have no moons at all:
Answer: Mercury, Venus
💡 Mercury and Venus are the only planets without moons, while Earth has one moon, Mars has two, and Jupiter has many.
Q132: Choose all the rocky planets from the list:
Answer: Mercury, Mars, Earth
💡 The rocky planets are the four closest to the sun: Mercury, Venus, Earth and Mars, while Jupiter and Saturn are gas giants.
Q133: A lunar eclipse happens when Earth is between the sun and the moon.
Answer: True ✔
💡 When Earth lines up between the sun and the moon, the moon falls into Earth's shadow and an eclipse happens, and the moon is full at that time.
Q134: A day on Jupiter (one spin on its axis) is longer than a day on Earth.
Answer: False ✖
💡 Jupiter spins on its axis faster than any other planet, so its day is only about 10 hours, even though it is the largest planet.
Q135: Venus spins on its axis in the opposite direction from most planets.
Answer: True ✔
💡 Venus spins on its axis very slowly and in the opposite direction from Earth, so on Venus the sun rises in the west and sets in the east.
Q136: It is safe to look directly at the sun with your eyes during a partial solar eclipse.
Answer: False ✖
💡 Looking at the sun, even when it is partly eclipsed, seriously harms the eyes, and special eclipse glasses must be used.
Q137: Many star names used around the world today are Arabic in origin, such as Aldebaran and Altair.
Answer: True ✔
💡 Europeans took many star names from Arab and Muslim astronomers, so al-Dabaran became Aldebaran and al-Ta'ir became Altair.
Q138: A light-year is a unit for measuring time.
Answer: False ✖
💡 A light-year is a unit of distance: the distance light travels in a whole year, about 9.5 trillion kilometers.
Q139: A comet's tail points away from the sun.
Answer: True ✔
💡 The solar wind and sunlight push the comet's gas and dust away from the sun, so the tail points in the opposite direction from the sun.
Q140: The four seasons happen because Earth moves closer to the sun in summer and farther away in winter.
Answer: False ✖
💡 The seasons are caused by the tilt of Earth's axis: when the Northern Hemisphere tilts toward the sun it has summer, and at the same time the Southern Hemisphere has winter.
Q141: People on Earth almost always see the same side of the moon.
Answer: True ✔
💡 The moon spins on its axis in the same time it takes to orbit Earth, so the same side always faces us.
Q142: Which planet is less dense than water?
Answer: Saturn
💡 Saturn is a gas planet whose average density is less than that of water, so in theory it would float in a tub of water big enough to hold it.
Q143: About how much of the mass of the whole solar system is the sun's mass?
Answer: More than 99%
💡 The sun is a giant compared to everything orbiting it; its mass alone is more than 99% of the mass of the solar system.
Q144: Which planet was the first to be discovered using a telescope?
Answer: Uranus
💡 The planets up to Saturn have been seen with the naked eye since ancient times, but Uranus was discovered by the astronomer William Herschel with a telescope in 1781.
Q145: Which planet is called the "morning star" and the "evening star" because it shines brightly near sunrise or sunset?
Answer: Venus
💡 Venus is a planet, not a star, but it shines very brightly near the horizon after sunset or before sunrise, so people called it the morning and evening star.
Q146: Which celestial body are the months of the Hijri calendar based on?
Answer: The moon
💡 The Hijri calendar is lunar; each month begins with the sighting of the crescent moon, which is why Ramadan moves through the seasons.
Q147: Why do astronauts' footprints stay on the moon's surface for a very long time?
Answer: Because the moon has no atmosphere, wind or rain to erase them
💡 On Earth, wind and rain quickly wipe away tracks, but the moon has no air or water, so the footprints last a very long time.
Q148: According to Kepler's laws, what shape are the planets' orbits around the sun?
Answer: Elliptical (oval)
💡 Johannes Kepler discovered that the planets orbit the sun in oval-shaped orbits, not in perfect circles.
Q149: What is the huge explosion with which some massive stars end their lives called?
Answer: A supernova
💡 Very massive stars end in a huge explosion called a supernova, which can briefly shine brighter than an entire galaxy.
Q150: What color are the hottest stars?
Answer: Blue
💡 A star's color shows its temperature: blue stars are the hottest, red stars the coolest, and the sun is in between.
Q151: What makes a black hole special?
Answer: Its gravity is so strong that not even light can escape it
💡 A black hole is a region where a huge mass is packed into a small space, so its gravity becomes so strong that not even light can escape from it.
Q152: What causes most meteor showers that come back on fixed dates every year?
Answer: Earth passing through dust left behind by comets
💡 Comets leave dust behind along their orbits, and when Earth passes through it each year, the particles burn up in the atmosphere, so we see many shooting stars.
Q153: About how often does Halley's Comet return to be seen from Earth?
Answer: About every 76 years
💡 Halley's Comet orbits the sun in a long orbit and returns to our sky about every 76 years, so most people see it only once in their lives.
Q154: What is the nucleus of a comet mainly made of?
Answer: Ice, dust and rock
💡 A comet's nucleus is like a dirty snowball of ice and dust; when it comes near the sun, its ice turns to gas and forms the tail.
Q155: What is the moon in relation to Earth?
Answer: A natural satellite that orbits it
💡 The moon is Earth's only permanent natural satellite; it orbits Earth and reflects sunlight.
Q156: What type of radiation was the James Webb Space Telescope mainly designed to observe?
Answer: Infrared radiation
💡 James Webb observes infrared radiation, so it can see what clouds of dust hide and capture the light of very distant galaxies.
Q157: Where does the Hubble Space Telescope operate?
Answer: In orbit around Earth
💡 Hubble was launched in 1990 to orbit Earth above its atmosphere, so it gets clearer images of stars and galaxies than telescopes on the ground.
Q158: Who was the first woman to travel to space, in 1963?
Answer: Valentina Tereshkova
💡 The Soviet cosmonaut Valentina Tereshkova went to space in 1963 and orbited Earth dozens of times.
Q159: Where did the two Saudi astronauts travel on their 2023 mission?
Answer: The International Space Station
💡 The two astronauts launched to the International Space Station, which orbits Earth, and carried out scientific experiments during their stay.
Q160: Who was the first Saudi female astronaut?
Answer: Rayyanah Barnawi
💡 Rayyanah Barnawi went to space in 2023 with her colleague Ali Alqarni, becoming the first Saudi woman to travel to space.
Q161: Who was the second person to walk on the moon, after Neil Armstrong in 1969?
Answer: Buzz Aldrin
💡 Buzz Aldrin stepped out minutes after Armstrong on the Apollo 11 mission, while their colleague Collins stayed in orbit around the moon.
Q162: What is the largest moon in the solar system?
Answer: Ganymede (a moon of Jupiter)
💡 Ganymede is the largest moon in the solar system, and its diameter is larger than that of the planet Mercury itself.
Q163: What is the astronomer Muhammad ibn Jabir al-Battani famous for?
Answer: Calculating the length of the solar year very accurately
💡 Al-Battani observed the sky for many years and calculated the length of the solar year very accurately, and in his honor a crater on the moon is named after him.
Q164: Which Muslim astronomer recorded the oldest known description of the Andromeda Galaxy in the 10th century CE?
Answer: Abd al-Rahman al-Sufi
💡 Abd al-Rahman al-Sufi described the Andromeda Galaxy in his "Book of Fixed Stars" as a "little cloud," centuries before the telescope was invented.
Q165: What shape is the Milky Way galaxy?
Answer: A spiral with arms
💡 The Milky Way is a spiral galaxy whose arms wind around its center, and the sun is in one of these arms, far from the center.
Q166: What is the name of the galaxy where our solar system is located?
Answer: The Milky Way
💡 Our solar system is part of the Milky Way galaxy; in Arabic it is called "Darb al-Tabbanah" (the path of the straw sellers) because in a dark sky it looks like a white band, like a trail of scattered straw.
Q167: About how long does sunlight take to reach Earth?
Answer: About 8 minutes
💡 Light travels the roughly 150 million kilometers between the sun and Earth in about 8 minutes, so we see the sun as it was 8 minutes earlier.
Q168: What is the source of the enormous energy the sun gives off?
Answer: Nuclear fusion in its core
💡 Inside the sun, hydrogen nuclei fuse to form helium, releasing enormous energy that reaches us as light and heat.
Q169: When is the tide usually at its highest?
Answer: At full moon and new moon, when the sun, moon and Earth line up
💡 When the sun, moon and Earth line up at full moon and new moon, their gravity combines, so the tide is at its highest.
Q170: What is the main cause of tides in the seas?
Answer: The moon's gravity
💡 The moon pulls on the sea waters, so they rise in some places and fall in others; the sun also has an effect, but it is smaller than the moon's.
Q171: Why does the moon look reddish during a total lunar eclipse?
Answer: Because Earth's atmosphere bends sunlight, so red light reaches the moon
💡 Even in a total lunar eclipse, some sunlight passes through Earth's atmosphere and bends toward the moon, and more red light reaches it than other colors.
Q172: In which phase is the moon when a solar eclipse happens?
Answer: New moon
💡 A solar eclipse happens when the moon passes between the sun and Earth; in this position its dark side faces us, that is, it is in the new moon phase.
Q173: Why does the moon's shape change between crescent and full during the month?
Answer: The lit part of the moon that we see changes as it orbits Earth
💡 The half of the moon facing the sun is always lit, and as the moon orbits Earth we see a part of this lit half that grows and then shrinks, creating the phases.
Q174: About how many days does the cycle of the moon's phases take, from one full moon to the next?
Answer: About 29.5 days
💡 The moon's phases repeat about every 29.5 days, which is why a lunar month has 29 or 30 days.
Q175: Where is the asteroid belt located in the solar system?
Answer: Between the orbits of Mars and Jupiter
💡 The asteroid belt is a region where huge numbers of rocks orbit between the orbits of Mars and Jupiter.
Q176: Which planet completes its orbit around the sun in the shortest time?
Answer: Mercury
💡 Mercury is the closest to the sun and the fastest planet in its orbit, so its year is only about 88 Earth days.
Q177: What are Saturn's rings mainly made of?
Answer: Countless pieces of ice and small rocks
💡 Saturn's rings are not one piece but billions of pieces of ice and rock, some the size of a grain of sand and some the size of a house.
Q178: Why is Venus hotter than Mercury, even though Mercury is closer to the sun?
Answer: Because its thick carbon dioxide atmosphere traps heat
💡 Venus is surrounded by a very thick atmosphere made mostly of carbon dioxide, which traps the sun's heat like a greenhouse until its surface is hot enough to melt lead.
Q179: Why does Mars appear reddish?
Answer: Because its soil is rich in iron oxide (rust)
💡 The surface of Mars is covered with dust and rocks containing iron oxide, the same substance that gives rust its red color.
Q180: How has Pluto been classified since 2006?
Answer: A dwarf planet
💡 In 2006, the International Astronomical Union set a new definition of a planet, so Pluto became a "dwarf planet" and the planets remained eight.
Q181: Match each food with the nutrient it is rich in:
Answer: Bread ↔ Carbohydrates, Meat ↔ Proteins, Butter ↔ Fats, Oranges ↔ Vitamin C
💡 Bread is a source of carbohydrates, which give energy; meat is rich in proteins for building the body; butter is fat; and oranges are rich in vitamin C.
Q182: Match each living thing with the group it belongs to:
Answer: Turtle ↔ Reptiles, Penguin ↔ Birds, Salmon ↔ Fish, Salamander ↔ Amphibians
💡 The turtle is a reptile covered with scales and has a shell, the penguin is a bird that cannot fly but has feathers, the salmon is a fish that breathes with gills, and the salamander is an amphibian whose young live in water.
Q183: Match each plant with the part of it that we eat:
Answer: Carrot ↔ The root, Spinach ↔ The leaves, Peas ↔ The seeds, Cauliflower ↔ The flowers
💡 We eat different parts of plants: the root of the carrot, the leaves of spinach, the seeds of peas, and the clustered flowers of cauliflower.
Q184: Order this food chain from the producer to the top predator:
Answer: Grass then Grasshopper then Frog then Snake then Falcon
💡 The grasshopper eats the grass, the frog eats the grasshopper, then the snake eats the frog, and the falcon hunts the snake.
Q185: Order the levels of organization in a living body from smallest to largest:
Answer: Cell then Tissue then Organ then System then Organism
💡 Similar cells group together to form a tissue, tissues form an organ such as the heart, organs form a system, and the systems together form the organism.
Q186: Order the stages of a butterfly's life cycle from the beginning:
Answer: The egg then The caterpillar (larva) then The pupa then The adult butterfly
💡 The caterpillar hatches from the egg and eats a lot, then turns into a pupa inside a protective case, and then the adult butterfly comes out.
Q187: Choose all the herbivores:
Answer: The gazelle, The rabbit, The giraffe
💡 The gazelle, rabbit and giraffe feed on plants, while the tiger and the wolf are carnivores.
Q188: Choose everything that can usually be seen only with a microscope:
Answer: Bacteria, Viruses
💡 Bacteria and viruses are so tiny that they usually cannot be seen with the naked eye, while we can see the ant and the earthworm with our own eyes.
Q189: Choose all the parts found in a flower:
Answer: Petals, Stamens, Pistil
💡 Colorful petals attract insects, stamens produce pollen, and the pistil contains the ovary, which becomes the fruit, while roots are underground.
Q190: Choose all the vertebrate animals:
Answer: The fish, The pigeon, The frog
💡 The fish, pigeon and frog have a backbone, while the earthworm and the snail are invertebrates.
Q191: Choose all the insects:
Answer: The ant, The bee, The butterfly
💡 The ant, bee and butterfly are insects, each with 6 legs, while the shrimp is a crustacean and the centipede is a myriapod, and both have more than 6 legs.
Q192: Choose everything a plant needs to carry out photosynthesis:
Answer: Sunlight, Water, Carbon dioxide gas
💡 A plant makes its food from water and carbon dioxide using the energy of sunlight absorbed by chlorophyll.
Q193: Plants stop breathing at night.
Answer: False ✖
💡 A plant is a living thing that breathes day and night, taking in oxygen and releasing carbon dioxide; it is photosynthesis that stops when there is no light.
Q194: The snake is an amphibian.
Answer: False ✖
💡 The snake is a reptile whose skin is covered with dry scales, while amphibians such as the frog have moist, smooth skin.
Q195: The octopus is an invertebrate animal.
Answer: True ✔
💡 The octopus has no backbone or skeleton, which is why it can squeeze its soft body through very small openings.
Q196: All plants reproduce with seeds.
Answer: False ✖
💡 Not all plants have seeds: ferns and mosses reproduce with tiny spores carried by wind and water.
Q197: An adult frog breathes with its lungs and also through its moist skin.
Answer: True ✔
💡 An adult frog has two lungs, and it can also absorb oxygen through its thin, moist skin, which is why it needs to stay near water.
Q198: Only about 10% of the energy at each level of the food pyramid passes to the next level.
Answer: True ✔
💡 Each organism uses most of its energy for moving, growing and breathing, so only about a tenth passes to the next level, which is why there are fewer organisms at the top of the pyramid.
Q199: Some living things have a body made of only one cell.
Answer: True ✔
💡 Bacteria and amoebas, for example, are single-celled organisms whose one cell carries out all the functions of life, while the human body is made of billions of cells.
Q200: All types of bacteria are harmful and cause disease.
Answer: False ✖
💡 Many bacteria are helpful, such as the bacteria that live in our intestines and help with digestion, and those that break down the remains of dead organisms.
Q201: Most viruses are much smaller than bacteria.
Answer: True ✔
💡 Most viruses are so small that they can only be seen with an electron microscope, while bacteria can be seen with an ordinary light microscope.
Q202: Which mammal lays eggs?
Answer: The platypus
💡 The platypus is one of the few mammals that lay eggs, but it feeds its young milk after they hatch, like other mammals.
Q203: Which of these traits does a person inherit from their parents?
Answer: Eye color
💡 Eye color is a hereditary trait passed on through genes, while language and riding a bike are learned, and a scar appears after birth.
Q204: What is the shape of the DNA molecule?
Answer: A double helix that looks like a twisted ladder
💡 A DNA molecule is made of two strands twisted around each other in a double helix that looks like a twisted ladder.
Q205: What is the name of the molecule that carries genetic information in the cells of living things?
Answer: DNA
💡 DNA carries the instructions that determine an organism's traits, and it is passed from parents to children.
Q206: For at least how many seconds should you scrub your hands with soap and water when washing them?
Answer: 20 seconds
💡 Scrubbing your hands with soap for at least 20 seconds removes most germs, and you can time it by singing a short song twice.
Q207: What does a vaccine do?
Answer: It trains the immune system to recognize a germ before infection
💡 A vaccine introduces the immune system to a germ, or part of one, without making the person sick, so if the germ attacks later, the body destroys it quickly.
Q208: Which blood cells defend the body and attack germs?
Answer: White blood cells
💡 White blood cells are the soldiers of the immune system; they recognize germs and attack them to protect the body from disease.
Q209: Which scientist discovered penicillin, the first well-known antibiotic?
Answer: Alexander Fleming
💡 In 1928, Alexander Fleming noticed that a mold growing in a dish in his lab was killing the bacteria around it, which was the start of the discovery of penicillin.
Q210: Which medicine kills bacteria but does not help treat viral diseases?
Answer: An antibiotic
💡 Antibiotics kill bacteria or stop them from growing, but they do not treat viruses such as the common cold, so they should only be taken with a doctor's prescription.
Q211: Which of these diseases is caused by a virus?
Answer: The flu
💡 The flu is a contagious disease caused by a virus, while rickets is caused by a lack of vitamin D, and anemia can result from a lack of iron.
Q212: What does a virus need in order to reproduce?
Answer: To enter a living cell of another organism
💡 A virus cannot reproduce on its own; it enters a living cell and uses it to make many copies of itself.
Q213: Which microorganisms turn milk into yogurt?
Answer: Helpful bacteria
💡 A helpful type of bacteria is added to warm milk; it turns the milk's sugar into acid, so the milk thickens and becomes yogurt.
Q214: Which living thing is added to dough to make it rise?
Answer: Yeast
💡 Yeast is a tiny fungus that feeds on the sugar in dough and releases carbon dioxide gas, forming bubbles that make the dough rise.
Q215: Which of these organisms is a fungus?
Answer: The mushroom
💡 The mushroom is a fungus; fungi are organisms that do not make their own food but feed on other materials around them.
Q216: Which microorganism is made of a single cell with no nucleus?
Answer: Bacteria
💡 A bacterial cell is simple and its genetic material is free with no nucleus, while yeast and amoeba cells have a nucleus, and a virus is not a cell at all.
Q217: Which level of the food pyramid contains the most energy?
Answer: The base of the pyramid, where the plants are
💡 Plants are at the base of the food pyramid and hold the most energy, and the energy decreases as we go up toward the top.
Q218: What do we call an animal that eats both plants and animals?
Answer: An omnivore
💡 An omnivore feeds on both plants and animals; examples include the bear and the crow.
Q219: Which of these insects goes through incomplete metamorphosis (egg, then nymph, then adult)?
Answer: The locust
💡 A young locust hatches from the egg as a nymph that looks like its parents but without full wings, while the butterfly, bee and beetle go through complete metamorphosis with a larva and a pupa.
Q220: What is the big change in an animal's shape during its life cycle, as happens with the butterfly and the frog, called?
Answer: Metamorphosis
💡 Metamorphosis is a major change in an animal's shape as it grows: the caterpillar becomes a butterfly, and the tadpole becomes a frog.
Q221: Which group of animals does the bat belong to?
Answer: Mammals
💡 The bat flies but it is not a bird; it is a mammal because its body is covered with hair and the female feeds her young milk.
Q222: Which feature do all mammals share?
Answer: They feed their young milk
💡 Mammals got their name because the females have mammary glands with which they feed their young milk.
Q223: What covers the bodies of reptiles such as lizards and crocodiles?
Answer: Dry scales
💡 Reptile skin is covered with dry scales that protect it and keep the body from losing water, unlike amphibians, which have moist skin.
Q224: What do fish breathe with?
Answer: Gills
💡 Fish take in oxygen dissolved in the water through the gills on both sides of their head.
Q225: Which feature do birds alone have among all the animals living today?
Answer: Feathers
💡 Feathers are found only in birds, while wings are also found in bats and insects, and many animals lay eggs.
Q226: How many legs does a spider have?
Answer: 8
💡 A spider has 8 legs, so it is not an insect; it belongs to the arachnid group, like the scorpion.
Q227: How many legs does an insect have?
Answer: 6
💡 Every insect has 6 legs, and its body is divided into three parts: the head, the thorax and the abdomen.
Q228: What sets vertebrate animals apart from others?
Answer: They have a backbone
💡 Vertebrates are animals with a backbone inside their bodies, such as fish, amphibians, reptiles, birds and mammals.
Q229: What is the transfer of pollen to the stigma of a flower called?
Answer: Pollination
💡 Pollination is the transfer of pollen to the stigma of a flower, usually with the help of insects or wind, and after it seeds form.
Q230: What is inside a seed?
Answer: A tiny plant (embryo) and stored food for it
💡 A seed holds a tiny baby plant (embryo) and stored food that it relies on at the start of its growth until its first leaves appear.
Q231: From which part of the plant does the fruit form?
Answer: The flower
💡 After pollination, part of the flower grows and turns into a fruit that protects the seeds inside it.
Q232: What is the function of the stem in a plant?
Answer: Supporting the plant and carrying water and food between the roots and the leaves
💡 The stem holds up the leaves and flowers, and it has tiny tubes that carry water from the roots to the leaves and carry food to the rest of the plant.
Q233: In which part of the plant does most photosynthesis take place?
Answer: The leaves
💡 Leaves are the plant's food factories: they are wide to catch as much sunlight as possible, and their cells are full of chloroplasts.
Q234: Which sugar does a plant make during photosynthesis?
Answer: Glucose
💡 The plant makes glucose from water and carbon dioxide using the energy of light, then stores some of it as starch.
Q235: What is the green pigment in plants that absorbs sunlight called?
Answer: Chlorophyll
💡 Chlorophyll is the pigment that gives plants their green color and absorbs the light needed to make food.
Q236: In which part of a plant cell does photosynthesis take place?
Answer: The chloroplasts
💡 Chloroplasts contain a green pigment that captures sunlight, and in them the plant makes its food.
Q237: Which structure is found in plant cells but not in animal cells, giving them a fixed shape and stiffness?
Answer: The cell wall
💡 The cell wall is a strong layer outside the membrane in plant cells, which is why plant cells look regular in shape.
Q238: Which part surrounds the cell and controls what enters and leaves it?
Answer: The cell membrane
💡 The cell membrane is a thin covering around the cell that lets certain substances pass and keeps others out.
Q239: Which part of the cell controls its activities and contains the genetic material?
Answer: The nucleus
💡 The nucleus is the cell's control center, and it holds the genetic material that carries the instructions for how the cell works and grows.
Q240: What is the smallest living unit that makes up the body of every living thing?
Answer: The cell
💡 The cell is the basic building block of life; every living thing is made of one cell or many cells.
Q241: The diaphragm is a muscle located below the lungs that helps us breathe.
Answer: True ✔
💡 When the diaphragm contracts and moves down, the lungs expand and air comes in (inhaling), and when it relaxes, air goes out (exhaling).
Q242: What tube carries food from the mouth to the stomach?
Answer: The esophagus
💡 After we swallow, food goes down the esophagus, and the muscles in its wall push it into the stomach, while the windpipe (trachea) is the air's path to the lungs.
Q243: A muscle can push a bone just as it can pull it.
Answer: False ✖
💡 A muscle works by contracting, so it can only pull a bone; that is why muscles work in pairs: one bends the arm and the other straightens it.
Q244: Which of these muscles works all the time without us controlling it on purpose?
Answer: The heart muscle
💡 The heart muscle contracts day and night throughout our lives without us thinking about it, while we move the muscles of the arm, leg and fingers whenever we want.
Q245: Which blood vessels carry blood from the heart to the rest of the body?
Answer: Arteries
💡 Arteries are vessels with thick, elastic walls that carry blood forcefully away from the heart to the body's organs, and we can feel their pulse in the wrist and neck.
Q246: What substance gives skin and hair their color?
Answer: Melanin
💡 Melanin is a pigment made by the skin; more of it means a darker color, and it helps protect the skin from the sun's rays.
Q247: The skin produces sweat to help cool the body.
Answer: True ✔
💡 When the body heats up in hot weather or during exercise, the skin produces sweat, and as the sweat evaporates, the body cools down.
Q248: Which body system is made up of the brain, the spinal cord and the nerves?
Answer: The nervous system
💡 The nervous system controls the whole body: the brain thinks and gives orders, and the spinal cord and nerves carry messages between it and the rest of the body.
Q249: What are the tiny receptors on the tongue that let us tell the taste of food called?
Answer: Taste buds
💡 The surface of the tongue has thousands of taste buds that detect sweet, salty, sour and bitter, and send that information to the brain.
Q250: The nose contains tiny hairs and mucus that help clean dust out of the air.
Answer: True ✔
💡 The hairs and mucus inside the nose trap dust and some germs, and the nose also warms and moistens the air before it reaches the lungs, which is why breathing through the nose is better.
Q251: An adult's heart at rest beats roughly 60 to 100 times a minute.
Answer: True ✔
💡 This is the normal resting heart rate for an adult. Children's heart rates are a little faster, and the heart rate goes up with running and playing.
Q252: What is the colored part of the eye, whose color differs from person to person?
Answer: The iris
💡 The iris is the colored part of the eye. It may be light brown, dark brown that looks black, hazel, green or blue, and it controls how wide the pupil opens.
Q253: A person can live a normal life with one healthy kidney.
Answer: True ✔
💡 One healthy kidney can do the work of two, which is why some people live normal lives with only one kidney.
Q254: The pupil of the eye gets smaller in bright light and bigger in the dark.
Answer: True ✔
💡 The pupil is an opening in the middle of the eye. The iris makes it smaller in bright light to protect the eye and bigger in the dark to let in more light so we can see.
Q255: The kidneys are in the upper chest, above the heart.
Answer: False ✖
💡 The kidneys are in the back of the abdomen on both sides of the spine, below the diaphragm, and each one is shaped like a bean.
Q256: The small intestine is shorter than the large intestine.
Answer: False ✖
💡 The small intestine got its name because it is narrower, but it is much longer: in an adult it is several meters long (about 6 meters), while the large intestine is about one and a half meters long.
Q257: Which healthy habit protects teeth from cavities?
Answer: Brushing your teeth with toothpaste twice a day
💡 Brushing your teeth with a toothbrush and toothpaste in the morning and before bed removes the food bits and germs that cause cavities.
Q258: What is the name of the thin membrane in the ear that vibrates when sounds reach it?
Answer: The eardrum
💡 Sounds are waves that enter the ear and make the eardrum vibrate. The vibrations travel through tiny bones to the inner ear and then to the brain.
Q259: What is the job of the muscles in the body?
Answer: Moving the body
💡 Muscles contract to pull on the bones and move them, so we use them to walk, write and smile, and some, like the heart muscle, work without us controlling them.
Q260: Put the journey of food through the digestive system in order from start to finish:
Answer: The mouth then The esophagus then The stomach then The small intestine then The large intestine
💡 Food is chewed in the mouth and goes down the esophagus to the stomach, then its digestion is completed and it is absorbed in the small intestine, and water is absorbed from the leftovers in the large intestine.
Q261: What is the place where two bones meet, like the knee and the elbow, called?
Answer: A joint
💡 Joints are the places where bones meet, and they let us bend the knee and elbow and move parts of the body.
Q262: What is the main job of the large intestine?
Answer: Absorbing water from food leftovers and forming waste
💡 After food is absorbed in the small intestine, the leftovers move to the large intestine, which absorbs water from them and forms the waste the body gets rid of.
Q263: Nerves carry messages between the brain and the parts of the body.
Answer: True ✔
💡 Nerves are like wires that carry sensations from the body to the brain and carry the brain's commands to the muscles in a fraction of a second.
Q264: Which part of the skeleton protects the heart and lungs?
Answer: The rib cage
💡 The ribs, together with the breastbone and the spine, form the rib cage, a bony shield that surrounds and protects the heart and lungs.
Q265: In which part of the body are the vocal cords that produce our voice?
Answer: The larynx
💡 The vocal cords are in the larynx. When the air we breathe out passes over them, they vibrate and produce the voice we speak with.
Q266: The tongue can taste sweetness only with its tip.
Answer: False ✖
💡 This is a common mistaken idea: taste buds are spread over the whole surface of the tongue, and every area of it can sense the different tastes.
Q267: What is the longest bone in the human body?
Answer: The thigh bone (femur)
💡 The thigh bone (femur) in the upper leg is the longest and strongest bone in the body, and it carries the body's weight when standing, walking and running.
Q268: The spinal cord runs inside the spine, which protects it.
Answer: True ✔
💡 The spinal cord is a bundle of nerves that connects the brain to the rest of the body. It runs through the openings of the vertebrae, so the spine protects it.
Q269: In which part of the digestive system is most digested food absorbed into the blood?
Answer: The small intestine
💡 The wall of the small intestine is full of tiny bumps called villi, which increase its surface area so it can absorb digested food and pass it into the blood.
Q270: Which mineral strengthens bones and teeth and is plentiful in milk and dairy products?
Answer: Calcium
💡 Calcium is one of the most important building blocks of bones and teeth, and we get it from milk, cheese, yogurt and some leafy vegetables.
Q271: How many pairs of ribs do most people have?
Answer: 12
💡 Most people have 12 pairs of ribs, or 24 ribs, all attached to the spine at the back, and together with the breastbone they form the rib cage.
Q272: The inner ear helps a person keep their balance.
Answer: True ✔
💡 The inner ear has fluid-filled canals that sense the movement of the head and tell the brain about it, so we keep our balance and don't fall.
Q273: Which organ is responsible for thinking and control?
Answer: The brain
💡 The brain is the body's control center: we use it to think, remember and learn, and it sends the commands that move the muscles and regulate the organs.
Q274: What is the hard white layer that covers a tooth and is the hardest substance in the human body?
Answer: Enamel
💡 Enamel covers the crown of the tooth and protects it, and it is the hardest substance in the body, but the acids made from leftover sugars can cause it to decay.
Q275: A child has 20 baby teeth.
Answer: True ✔
💡 A child has 20 baby teeth, which usually start falling out at about age 6, to be replaced by permanent teeth.
Q276: Which vitamin is linked to eye health and seeing in dim light, and is made by the body from a substance found in large amounts in carrots?
Answer: Vitamin A
💡 Vitamin A is important for eye health and seeing in dim light. Carrots are rich in an orange substance called beta-carotene, which the body turns into vitamin A, and it is also found in eggs and milk.
Q277: What strong tissue connects a muscle to a bone?
Answer: A tendon
💡 Tendons are strong cords that connect muscles to bones. When a muscle contracts, the tendon pulls the bone and makes it move. One of the best known is the Achilles tendon above the heel.
Q278: What happens to your heartbeat when you run?
Answer: It speeds up to deliver more oxygen to the muscles
💡 While running, the muscles need more oxygen and energy, so the heart beats faster to pump more blood to them, then returns to normal after resting.
Q279: Why do we need to drink more water on hot days and after exercise?
Answer: To replace the water the body loses through sweat
💡 The body loses a lot of water through sweat in hot weather and during exercise, so we drink water to replace it and protect the body from dehydration.
Q280: How many hours of sleep each night are recommended for children aged 6 to 12?
Answer: 9 to 12 hours
💡 Doctors recommend that children this age sleep 9 to 12 hours a night, because enough sleep helps with growth, focus and learning.
Q281: Put these teeth in order from the front of the mouth to the back:
Answer: Incisors then Canines then Premolars then Molars
💡 The incisors at the front cut food, followed by the canines that tear it, then the premolars and molars at the back that grind it.
Q282: The rib cage is made of one large bone.
Answer: False ✖
💡 The rib cage is made of many bones: 24 ribs, the breastbone (sternum) in front, and the vertebrae of the back behind.
Q283: Put in order the path air takes when we breathe in, from outside to inside:
Answer: The nose then The larynx then The windpipe (trachea) then The lungs
💡 Air enters through the nose, then passes through the larynx, then the windpipe (trachea), which splits into two branches that enter the lungs.
Q284: Match each organ to the system it belongs to:
Answer: The heart ↔ The circulatory system, The lungs ↔ The respiratory system, The stomach ↔ The digestive system, The brain ↔ The nervous system
💡 Each system in the body has organs that work together: the heart pumps blood, the lungs are for breathing, the stomach digests food, and the brain controls the body.
Q285: The stomach produces an acidic juice that helps digest food.
Answer: True ✔
💡 The stomach walls produce an acidic juice that breaks down food and starts digesting proteins, and it also kills many germs that come in with food.
Q286: Choose everything that blood carries in the human body:
Answer: Oxygen, Digested food, Carbon dioxide
💡 Blood carries oxygen and digested food to the cells and takes carbon dioxide and waste away from them, while saliva is produced by the glands of the mouth, inside the mouth.
Q287: Choose all the habits that keep the heart healthy:
Answer: Exercising and moving regularly, Eating vegetables and fruits
💡 Regular movement and a balanced diet make the heart stronger, while too little movement and smoking harm the heart and blood vessels.
Q288: How many chambers are there in the human heart?
Answer: 4
💡 The human heart has 4 chambers: two atria at the top that receive blood, and two ventricles at the bottom that pump it out of the heart.
Q289: Choose all the organs of the digestive system:
Answer: The stomach, The esophagus, The small intestine
💡 The stomach, the esophagus and the small intestine are part of the digestive system, while the lungs belong to the respiratory system and the kidneys to the urinary system.
Q290: How do the eyelids and eyelashes help the eye?
Answer: They protect the eye from dust and very bright light
💡 Eyelashes keep dust out of the eye, the eyelids close when there is danger or very bright light, and with every blink tears spread to clean and moisten the eye.
Q291: Which part of the eye receives the image and turns it into signals that the optic nerve carries to the brain?
Answer: The retina
💡 The image forms on the retina at the back of the eye, which turns it into nerve signals. The optic nerve carries them to the brain, which interprets them so we can see.
Q292: Which gas do the cells produce that the body gets rid of when we breathe out?
Answer: Carbon dioxide
💡 Cells use oxygen to produce energy, which creates carbon dioxide gas. The blood carries it to the lungs, and we breathe it out.
Q293: Why can we taste our food less when we have a stuffy nose from a cold?
Answer: Because the sense of smell helps us recognize the flavor of food
💡 The flavor of food comes from taste and smell together, so when the nose is blocked, fewer smells get through and food seems almost tasteless.
Q294: An adult has more bones than a newborn baby.
Answer: False ✖
💡 The opposite is true: a baby is born with about 300 bones, and some of them fuse together during growth until there are 206 bones in an adult.
Q295: What are the tiny air sacs inside the lungs, from which oxygen passes into the blood, called?
Answer: Alveoli
💡 The lungs contain millions of alveoli surrounded by tiny blood capillaries. Oxygen passes from them into the blood, and carbon dioxide passes from the blood into them.
Q296: What substance in red blood cells carries oxygen and gives blood its red color?
Answer: Hemoglobin
💡 Hemoglobin is a protein containing iron. It picks up oxygen in the lungs and delivers it to the cells, and it is what makes blood red.
Q297: What are the tiny parts of the blood that help it clot and stop bleeding from a cut?
Answer: Platelets
💡 When you get a cut, platelets gather at the spot and help form a small clot that seals the wound, so the bleeding stops.
Q298: Which hormone does the pancreas release to control the blood sugar level?
Answer: Insulin
💡 The pancreas releases the hormone insulin, which helps sugar move from the blood into the cells, keeping the blood sugar level where it should be.
Q299: What is the largest gland in the human body?
Answer: The liver
💡 The liver is the largest gland in the body. It is in the upper right part of the abdomen, and one of its jobs is making bile, which helps digest fats.
Q300: What liquid does the mouth produce to moisten food, make it easier to swallow, and start digesting it?
Answer: Saliva
💡 The salivary glands release saliva into the mouth. It moistens food, makes chewing and swallowing easier, and starts digesting starches.
Q301: Which two organs clean waste from the blood and make urine?
Answer: The kidneys
💡 A large amount of blood passes through the kidneys every day; they filter out waste and extra water and get rid of them as urine.
Q302: An adult at rest breathes about 100 times a minute.
Answer: False ✖
💡 An adult at rest breathes roughly 12 to 20 times a minute. Children breathe a little faster, and breathing speeds up with movement and exercise.
Q303: Identical twins have exactly the same fingerprints.
Answer: False ✖
💡 Even identical twins have different fingerprints. Every person has their own unique fingerprints, which is why they are used to identify people.
Q304: The blood inside veins is blue.
Answer: False ✖
💡 Blood is always red, but in the veins it is dark red because it has less oxygen. Veins only look blue when seen through the skin.
Q305: People feel pain when the parts of their hair and nails that stick out are cut.
Answer: False ✖
💡 The visible part of hair and nails has no nerves, so cutting it does not hurt, but the skin they grow from is sensitive.
Q306: Bones are made of dead material that does not grow or repair itself.
Answer: False ✖
💡 Bones are living tissue with cells and blood vessels. They grow as a person grows, and if a bone breaks it knits back together after being held in place.
Q307: Blood leaves the heart for the parts of the body and never returns to it.
Answer: False ✖
💡 Blood travels around the body in a continuous loop: it leaves the heart through the arteries and returns through the veins, which is why it is called the circulatory system.
Q308: Jupiter is a rocky planet that you can stand on.
Answer: False ✖
💡 Jupiter is a gas giant made mostly of hydrogen and helium, and it has no solid surface to stand on.
Q309: Why can't we see the stars during the day?
Answer: Because the bright sunlight outshines their faint light
💡 The stars are in the sky during the day too, but the light of the nearby Sun is much stronger and outshines them.
Q310: A rocket needs a very high speed to overcome Earth's gravity and reach space.
Answer: True ✔
💡 Earth's gravity pulls everything toward it, so rockets need very powerful engines to launch at tremendous speed and reach space.
Q311: Which vehicle blasts off with the power of its engines to carry astronauts and satellites into space?
Answer: A rocket
💡 A rocket burns its fuel and shoots upward at a tremendous speed, fast enough to reach space, while an airplane flies only within the air.
Q312: What is the closest star to Earth?
Answer: The Sun
💡 The Sun is a star like the others, but it is the closest one to us, which is why it looks big and we feel its heat.
Q313: Which icy object grows a glowing tail when it gets close to the Sun?
Answer: A comet
💡 A comet is a lump of ice and dust. When it gets close to the Sun, some of its ice turns to gas, and a long, glowing tail appears.
Q314: The shooting stars we see at night are real stars falling from the sky.
Answer: False ✖
💡 Shooting stars (meteors) are small space rocks burning up in the atmosphere, while stars are huge suns very far away from us that do not fall.
Q315: Earth is shaped like a ball.
Answer: True ✔
💡 Pictures from space show Earth as a ball, slightly flattened at the poles.
Q316: What do we call the enormous system that contains billions of stars along with gas and dust?
Answer: A galaxy
💡 A galaxy is a huge collection of billions of stars, and the solar system is a very small part of our galaxy.
Q317: Choose all the planets among these objects:
Answer: Mars, Saturn, Neptune
💡 Mars, Saturn and Neptune are among the eight planets of the solar system, while the Moon is Earth's satellite and the Sun is a star.
Q318: What is the Sun mainly made of?
Answer: Extremely hot gases, mainly hydrogen and helium
💡 The Sun is a huge ball of burning gases, mostly hydrogen and helium.
Q319: Saturn's rings can easily be seen with the naked eye.
Answer: False ✖
💡 To the naked eye, Saturn looks like just a bright dot; to see its rings you need a telescope, even a small one.
Q320: Match each word to its meaning:
Answer: Asteroid ↔ A space rock that orbits the Sun, Astronomer ↔ A scientist who studies stars and planets, Horizon ↔ The line where the sky seems to meet the Earth, Observatory ↔ A building with telescopes for watching the sky
💡 Asteroids are rocks that orbit the Sun, an astronomer is a scientist who studies objects in the sky, the horizon is where the sky seems to touch the Earth, and an observatory is a place equipped with telescopes.
Q321: The brightest object we usually see in the night sky is the Moon.
Answer: True ✔
💡 The Moon is usually the brightest thing we see in the night sky because it is very close to us and reflects the sunlight that falls on it.
Q322: What do we call a device made by humans that orbits Earth to carry communications and watch the weather?
Answer: An artificial satellite
💡 Artificial satellites are devices that people launch on rockets to orbit Earth, where they carry broadcasts, communications and weather images.
Q323: What do we call a space rock that reaches Earth's surface without burning up completely in the air?
Answer: A meteorite
💡 Most space rocks burn up in the atmosphere, and those that reach Earth's surface are called meteorites.
Q324: Jupiter can be seen from Earth with the naked eye.
Answer: True ✔
💡 At night Jupiter appears as a very bright dot that does not twinkle like the stars, and it can be seen without a telescope at many times of the year.
Q325: Stars are smaller than the Moon because they look like tiny dots to us.
Answer: False ✖
💡 Stars are huge suns, many of them bigger than our Sun, and they look like tiny dots because they are very far away from us.
Q326: Sound travels in space the same way it travels through air.
Answer: False ✖
💡 Sound needs air or some other material to travel through, and space has almost no air, so astronauts talk to each other using radios.
Q327: The Sun is smaller than Earth.
Answer: False ✖
💡 The Sun is much bigger than Earth; it could hold more than a million Earth-sized balls. It looks small because it is far away from us.
Q328: Earth is the only planet known so far to have life on it.
Answer: True ✔
💡 Scientists have not found life on any other planet. Earth has the water, air and right temperatures for life.
Q329: The North Star is the brightest star in the night sky.
Answer: False ✖
💡 The North Star is famous for staying fixed above the north, not for its brightness. The brightest star in the night sky is Sirius.
Q330: There is enough air to breathe on the surface of the Moon.
Answer: False ✖
💡 The Moon has almost no atmosphere, so astronauts wear suits that carry oxygen when they walk on its surface.
Q331: The Sun is one of billions of stars in our galaxy.
Answer: True ✔
💡 Our galaxy has billions of stars, and the Sun is one of them. It looks like the biggest to us because it is the closest.
Q332: About how long does it take Earth to spin all the way around once on its axis?
Answer: 24 hours
💡 Earth spins once on its axis about every 24 hours, and this period is one day, night and daytime together.
Q333: What do we call the streak of light that appears in the sky when a small space rock burns up in the atmosphere?
Answer: A meteor
💡 When a small space rock enters the atmosphere at high speed, it burns up, and we see a quick streak of light called a meteor (shooting star).
Q334: What is the name of the path a planet follows as it goes around the Sun?
Answer: An orbit
💡 An orbit is the path in which one object goes around another, like Earth's orbit around the Sun and the Moon's orbit around Earth.
Q335: What is the name of one of the two moons of Mars?
Answer: Phobos
💡 Mars has two small moons, Phobos and Deimos. Titan is a moon of Saturn, and Ganymede and Europa are moons of Jupiter.
Q336: What do we call a spacecraft sent to explore planets and space with no astronauts on board?
Answer: A space probe
💡 A space probe is an uncrewed robotic spacecraft that carries instruments and cameras and sends data and pictures back to scientists on Earth.
Q337: Which planet's orbit lies between the orbits of Mercury and Earth?
Answer: Venus
💡 Venus is the second planet from the Sun, so its orbit lies between that of Mercury, the first, and that of Earth, the third.
Q338: The Moon is much smaller than Earth.
Answer: True ✔
💡 The Moon's diameter is about one-quarter of Earth's, so its gravity is weaker than Earth's.
Q339: What keeps the Moon going around in its orbit around Earth?
Answer: Earth's gravity
💡 Earth's gravity constantly pulls the Moon toward it, so the Moon keeps circling Earth instead of drifting off into space.
Q340: What do we call a group of stars that appears in the sky in a familiar shape, like the Big Dipper (Great Bear)?
Answer: A constellation
💡 A constellation is a group of stars that people connect in their imagination into a familiar shape, like the Great Bear and Orion.
Q341: Mars is bigger than Earth.
Answer: False ✖
💡 Mars is about half the diameter of Earth, so it is smaller than Earth, though it is bigger than Mercury.
Q342: Choose all the things made by humans:
Answer: An artificial satellite, A space probe, The International Space Station
💡 Artificial satellites, space probes and the space station are devices made by humans and launched on rockets, while comets and meteors are natural objects.
Q343: Which of these objects orbits Earth?
Answer: The Moon
💡 The Moon is a satellite that orbits Earth, while Earth, Mars and Venus all orbit the Sun.
Q344: Earth has two natural moons orbiting it.
Answer: False ✖
💡 Earth has only one natural moon: the Moon we see in the sky.
Q345: Choose all the planets that are closer to the Sun than Earth:
Answer: Mercury, Venus
💡 Earth is the third planet, so only two planets are closer to the Sun: Mercury and Venus.
Q346: What device do astronomers use to see distant stars and planets clearly?
Answer: A telescope
💡 A telescope gathers the light coming from distant objects, making them look bigger and clearer.
Q347: What do we call a person trained to travel into space?
Answer: An astronaut
💡 An astronaut trains for a long time to travel into space, while an astronomer studies stars and planets, usually from Earth.
Q348: Match each object to its type:
Answer: The Sun ↔ Star, Mars ↔ Rocky planet, Halley ↔ Comet, Saturn ↔ Gas giant planet
💡 The Sun is a star that shines with its own light, Mars is a rocky planet, Halley is a famous comet, and Saturn is a gas giant planet.
Q349: Match each planet to its position from the Sun:
Answer: Mercury ↔ First, Earth ↔ Third, Saturn ↔ Sixth, Neptune ↔ Eighth
💡 The order of the planets is: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
Q350: Which planet comes right after Saturn in distance from the Sun?
Answer: Uranus
💡 Saturn is the sixth planet, followed by Uranus seventh, then Neptune eighth and last.
Q351: Put these objects in order from closest to Earth to farthest from it:
Answer: The Moon then The Sun then Neptune then The North Star
💡 The Moon is the closest object to us, the Sun is much farther away, Neptune is farther than the Sun, and the North Star is a very distant star outside our solar system.
Q352: What is the smallest planet in the solar system?
Answer: Mercury
💡 Mercury is the smallest of the eight planets. It is bigger than our Moon but much smaller than Earth.
Q353: What is the name of the layer of air that surrounds Earth and that we breathe?
Answer: The atmosphere
💡 The atmosphere is a layer of air surrounding Earth. We breathe it, and it protects us from many space rocks, which burn up in it.
Q354: Which planet comes right after Mars in distance from the Sun?
Answer: Jupiter
💡 After Mars (the fourth planet) comes Jupiter, fifth, which is the largest planet.
Q355: Put these giant planets in order from closest to the Sun to farthest from it:
Answer: Jupiter then Saturn then Uranus then Neptune
💡 After Mars come the giant planets: Jupiter fifth, then Saturn, then Uranus, then Neptune, the farthest.
Q356: What is the name of the huge laboratory where astronauts live for months while it orbits Earth?
Answer: The International Space Station
💡 The International Space Station is a home and laboratory that orbits Earth, where astronauts from different countries live and carry out scientific experiments.
Q357: Which planet is fourth from the Sun?
Answer: Mars
💡 The order of the first planets from the Sun is Mercury, then Venus, then Earth, then Mars fourth.
Q358: The Sun is what goes around the Earth.
Answer: False ✖
💡 Earth is what goes around the Sun, and sunrise and sunset happen because Earth spins on its axis.
Q359: The North Star shows roughly which way is north.
Answer: True ✔
💡 The North Star stays almost fixed in place above the north, so travelers in the desert and at sea used it to find their way long ago.
Q360: Stars seem to twinkle because their light passes through the moving air of the atmosphere.
Answer: True ✔
💡 The light of a distant star wobbles as it passes through the moving layers of air above us, so we see it twinkle. From space, stars look steady and do not twinkle.
Q361: Why does an astronaut wear a special suit when going out of the spacecraft into space?
Answer: To give them oxygen and protect them from extreme cold and heat
💡 Space has no air to breathe and its temperatures are harsh, so the spacesuit carries oxygen and protects the astronaut like a small spacecraft made to fit.
Q362: What force makes a ball fall back to the ground when we throw it up?
Answer: Gravity
💡 Gravity is a force that pulls objects toward Earth, which is why everything we throw up comes falling back down.
Q363: Which planet is called "Earth's twin" because it is close to Earth in size?
Answer: Venus
💡 Venus is called Earth's twin because it is close to Earth in size and mass, but its surface is extremely hot and cannot support life.
Q364: Put these planets in order from closest to the Sun to farthest from it:
Answer: Mercury then Venus then Earth then Mars
💡 These are the four rocky planets close to the Sun: Mercury first, then Venus, then Earth, then Mars.
Q365: Which planet in the solar system is farthest from the Sun?
Answer: Neptune
💡 Neptune is the eighth planet and the farthest from the Sun, so it needs about 165 Earth years to complete one trip around it.
Q366: Why is Earth called the "Blue Planet"?
Answer: Because water covers more than two-thirds of its surface
💡 Earth looks blue from space because oceans and seas cover most of its surface.
Q367: What is the fifth number in the pattern: 29, 34, 39, 44, ?
Answer: 49
💡 The pattern goes up by 5 each time: 44 + 5 = 49.
Q368: What is the fifth number in the pattern: 56, 64, 72, 80, ?
Answer: 88
💡 The pattern goes up by 8 each time: 80 + 8 = 88.
Q369: What is the fifth number in the pattern: 26, 37, 48, 59, ?
Answer: 70
💡 The pattern goes up by 11 each time: 59 + 11 = 70.
Q370: What is the fifth number in the pattern: 50, 61, 72, 83, ?
Answer: 94
💡 The pattern goes up by 11 each time: 83 + 11 = 94.
Q371: What is the fifth number in the pattern: 10, 12, 14, 16, ?
Answer: 18
💡 The pattern goes up by 2 each time: 16 + 2 = 18.
Q372: What is the fifth number in the pattern: 15, 22, 29, 36, ?
Answer: 43
💡 The pattern goes up by 7 each time: 36 + 7 = 43.
Q373: What is the fifth number in the pattern: 31, 34, 37, 40, ?
Answer: 43
💡 The pattern goes up by 3 each time: 40 + 3 = 43.
Q374: What is the fifth number in the pattern: 1, 4, 7, 10, ?
Answer: 13
💡 The pattern goes up by 3 each time: 10 + 3 = 13.
Q375: What is the fifth number in the pattern: 7, 13, 19, 25, ?
Answer: 31
💡 The pattern goes up by 6 each time: 25 + 6 = 31.
Q376: What is the fifth number in the pattern: 43, 50, 57, 64, ?
Answer: 71
💡 The pattern goes up by 7 each time: 64 + 7 = 71.
Q377: What is the fifth number in the pattern: 26, 38, 50, 62, ?
Answer: 74
💡 The pattern goes up by 12 each time: 62 + 12 = 74.
Q378: What is the fifth number in the pattern: 8, 13, 18, 23, ?
Answer: 28
💡 The pattern goes up by 5 each time: 23 + 5 = 28.
Q379: What is the fifth number in the pattern: 41, 47, 53, 59, ?
Answer: 65
💡 The pattern goes up by 6 each time: 59 + 6 = 65.
Q380: What is the fifth number in the pattern: 43, 45, 47, 49, ?
Answer: 51
💡 The pattern goes up by 2 each time: 49 + 2 = 51.
Q381: What is the fifth number in the pattern: 49, 59, 69, 79, ?
Answer: 89
💡 The pattern goes up by 10 each time: 79 + 10 = 89.
Q382: What is the fifth number in the pattern: 26, 34, 42, 50, ?
Answer: 58
💡 The pattern goes up by 8 each time: 50 + 8 = 58.
Q383: What is the fifth number in the pattern: 59, 61, 63, 65, ?
Answer: 67
💡 The pattern goes up by 2 each time: 65 + 2 = 67.
Q384: What is the fifth number in the pattern: 13, 25, 37, 49, ?
Answer: 61
💡 The pattern goes up by 12 each time: 49 + 12 = 61.
Q385: What is the fifth number in the pattern: 8, 16, 24, 32, ?
Answer: 40
💡 The pattern goes up by 8 each time: 32 + 8 = 40.
Q386: What is the fifth number in the pattern: 43, 54, 65, 76, ?
Answer: 87
💡 The pattern goes up by 11 each time: 76 + 11 = 87.
Q387: What is the fifth number in the pattern: 14, 24, 34, 44, ?
Answer: 54
💡 The pattern goes up by 10 each time: 44 + 10 = 54.
Q388: What is the fifth number in the pattern: 46, 49, 52, 55, ?
Answer: 58
💡 The pattern goes up by 3 each time: 55 + 3 = 58.
Q389: What is the fifth number in the pattern: 13, 15, 17, 19, ?
Answer: 21
💡 The pattern goes up by 2 each time: 19 + 2 = 21.
Q390: What is the fifth number in the pattern: 38, 50, 62, 74, ?
Answer: 86
💡 The pattern goes up by 12 each time: 74 + 12 = 86.
Q391: What is the fifth number in the pattern: 19, 25, 31, 37, ?
Answer: 43
💡 The pattern goes up by 6 each time: 37 + 6 = 43.
Q392: What is the fifth number in the pattern: 51, 55, 59, 63, ?
Answer: 67
💡 The pattern goes up by 4 each time: 63 + 4 = 67.
Q393: What is the fifth number in the pattern: 46, 56, 66, 76, ?
Answer: 86
💡 The pattern goes up by 10 each time: 76 + 10 = 86.
Q394: What is the fifth number in the pattern: 1, 10, 19, 28, ?
Answer: 37
💡 The pattern goes up by 9 each time: 28 + 9 = 37.
Q395: What is the fifth number in the pattern: 48, 53, 58, 63, ?
Answer: 68
💡 The pattern goes up by 5 each time: 63 + 5 = 68.
Q396: What is the fifth number in the pattern: 49, 51, 53, 55, ?
Answer: 57
💡 The pattern goes up by 2 each time: 55 + 2 = 57.
Q397: What is the fifth number in the pattern: 49, 52, 55, 58, ?
Answer: 61
💡 The pattern goes up by 3 each time: 58 + 3 = 61.
Q398: What is the fifth number in the pattern: 30, 33, 36, 39, ?
Answer: 42
💡 The pattern goes up by 3 each time: 39 + 3 = 42.
Q399: What is the fifth number in the pattern: 52, 58, 64, 70, ?
Answer: 76
💡 The pattern goes up by 6 each time: 70 + 6 = 76.
Q400: What is the fifth number in the pattern: 7, 16, 25, 34, ?
Answer: 43
💡 The pattern goes up by 9 each time: 34 + 9 = 43.
Q401: What is the fifth number in the pattern: 4, 14, 24, 34, ?
Answer: 44
💡 The pattern goes up by 10 each time: 34 + 10 = 44.
Q402: What is the fifth number in the pattern: 42, 53, 64, 75, ?
Answer: 86
💡 The pattern goes up by 11 each time: 75 + 11 = 86.
Q403: What is the fifth number in the pattern: 15, 27, 39, 51, ?
Answer: 63
💡 The pattern goes up by 12 each time: 51 + 12 = 63.
Q404: What is the fifth number in the pattern: 12, 19, 26, 33, ?
Answer: 40
💡 The pattern goes up by 7 each time: 33 + 7 = 40.
Q405: What is the fifth number in the pattern: 5, 14, 23, 32, ?
Answer: 41
💡 The pattern goes up by 9 each time: 32 + 9 = 41.
Q406: What is the fifth number in the pattern: 16, 25, 34, 43, ?
Answer: 52
💡 The pattern goes up by 9 each time: 43 + 9 = 52.
Q407: What is the fifth number in the pattern: 20, 22, 24, 26, ?
Answer: 28
💡 The pattern goes up by 2 each time: 26 + 2 = 28.
Q408: What is the fifth number in the pattern: 6, 16, 26, 36, ?
Answer: 46
💡 The pattern goes up by 10 each time: 36 + 10 = 46.
Q409: What is the fifth number in the pattern: 34, 38, 42, 46, ?
Answer: 50
💡 The pattern goes up by 4 each time: 46 + 4 = 50.
Q410: What is the fifth number in the pattern: 23, 27, 31, 35, ?
Answer: 39
💡 The pattern goes up by 4 each time: 35 + 4 = 39.
Q411: What is the fifth number in the pattern: 45, 53, 61, 69, ?
Answer: 77
💡 The pattern goes up by 8 each time: 69 + 8 = 77.
Q412: What is the fifth number in the pattern: 49, 53, 57, 61, ?
Answer: 65
💡 The pattern goes up by 4 each time: 61 + 4 = 65.
Q413: What is the fifth number in the pattern: 30, 35, 40, 45, ?
Answer: 50
💡 The pattern goes up by 5 each time: 45 + 5 = 50.
Q414: What is the fifth number in the pattern: 41, 50, 59, 68, ?
Answer: 77
💡 The pattern goes up by 9 each time: 68 + 9 = 77.
Q415: What is the fifth number in the pattern: 21, 32, 43, 54, ?
Answer: 65
💡 The pattern goes up by 11 each time: 54 + 11 = 65.
Q416: What is the fifth number in the pattern: 50, 55, 60, 65, ?
Answer: 70
💡 The pattern goes up by 5 each time: 65 + 5 = 70.
Q417: What is the fifth number in the pattern: 29, 33, 37, 41, ?
Answer: 45
💡 The pattern goes up by 4 each time: 41 + 4 = 45.
Q418: What is the fifth number in the pattern: 16, 21, 26, 31, ?
Answer: 36
💡 The pattern goes up by 5 each time: 31 + 5 = 36.
Q419: What is the fifth number in the pattern: 48, 50, 52, 54, ?
Answer: 56
💡 The pattern goes up by 2 each time: 54 + 2 = 56.
Q420: What is the fifth number in the pattern: 57, 69, 81, 93, ?
Answer: 105
💡 The pattern goes up by 12 each time: 93 + 12 = 105.
Q421: What is the fifth number in the pattern: 33, 37, 41, 45, ?
Answer: 49
💡 The pattern goes up by 4 each time: 45 + 4 = 49.
Q422: What is the fifth number in the pattern: 32, 36, 40, 44, ?
Answer: 48
💡 The pattern goes up by 4 each time: 44 + 4 = 48.
Q423: What is the fifth number in the pattern: 39, 47, 55, 63, ?
Answer: 71
💡 The pattern goes up by 8 each time: 63 + 8 = 71.
Q424: What is the fifth number in the pattern: 35, 42, 49, 56, ?
Answer: 63
💡 The pattern goes up by 7 each time: 56 + 7 = 63.
Q425: What is the fifth number in the pattern: 49, 55, 61, 67, ?
Answer: 73
💡 The pattern goes up by 6 each time: 67 + 6 = 73.
Q426: What is the fifth number in the pattern: 30, 38, 46, 54, ?
Answer: 62
💡 The pattern goes up by 8 each time: 54 + 8 = 62.
Q427: What is the fifth number in the pattern: 23, 25, 27, 29, ?
Answer: 31
💡 The pattern goes up by 2 each time: 29 + 2 = 31.
Q428: What is the fifth number in the pattern: 29, 37, 45, 53, ?
Answer: 61
💡 The pattern goes up by 8 each time: 53 + 8 = 61.
Q429: What is the fifth number in the pattern: 40, 43, 46, 49, ?
Answer: 52
💡 The pattern goes up by 3 each time: 49 + 3 = 52.
Q430: What is the fifth number in the pattern: 27, 36, 45, 54, ?
Answer: 63
💡 The pattern goes up by 9 each time: 54 + 9 = 63.
Q431: What is the fifth number in the pattern: 24, 28, 32, 36, ?
Answer: 40
💡 The pattern goes up by 4 each time: 36 + 4 = 40.
Q432: What is the fifth number in the pattern: 6, 13, 20, 27, ?
Answer: 34
💡 The pattern goes up by 7 each time: 27 + 7 = 34.
Q433: What is the fifth number in the pattern: 52, 62, 72, 82, ?
Answer: 92
💡 The pattern goes up by 10 each time: 82 + 10 = 92.
Q434: What is the fifth number in the pattern: 57, 62, 67, 72, ?
Answer: 77
💡 The pattern goes up by 5 each time: 72 + 5 = 77.
Q435: What is the fifth number in the pattern: 55, 67, 79, 91, ?
Answer: 103
💡 The pattern goes up by 12 each time: 91 + 12 = 103.
Q436: What is the fifth number in the pattern: 48, 59, 70, 81, ?
Answer: 92
💡 The pattern goes up by 11 each time: 81 + 11 = 92.
Q437: What is the fifth number in the pattern: 14, 23, 32, 41, ?
Answer: 50
💡 The pattern goes up by 9 each time: 41 + 9 = 50.
Q438: What is the fifth number in the pattern: 43, 46, 49, 52, ?
Answer: 55
💡 The pattern goes up by 3 each time: 52 + 3 = 55.
Q439: What is the fifth number in the pattern: 1, 13, 25, 37, ?
Answer: 49
💡 The pattern goes up by 12 each time: 37 + 12 = 49.
Q440: What is the fifth number in the pattern: 3, 8, 13, 18, ?
Answer: 23
💡 The pattern goes up by 5 each time: 18 + 5 = 23.
Q441: What is the fifth number in the pattern: 23, 26, 29, 32, ?
Answer: 35
💡 The pattern goes up by 3 each time: 32 + 3 = 35.
Q442: What is the fifth number in the pattern: 12, 14, 16, 18, ?
Answer: 20
💡 The pattern goes up by 2 each time: 18 + 2 = 20.
Q443: What is the fifth number in the pattern: 33, 35, 37, 39, ?
Answer: 41
💡 The pattern goes up by 2 each time: 39 + 2 = 41.
Q444: What is the fifth number in the pattern: 4, 8, 12, 16, ?
Answer: 20
💡 The pattern goes up by 4 each time: 16 + 4 = 20.
Q445: What is the fifth number in the pattern: 3, 5, 7, 9, ?
Answer: 11
💡 The pattern goes up by 2 each time: 9 + 2 = 11.
Q446: What is the fifth number in the pattern: 9, 17, 25, 33, ?
Answer: 41
💡 The pattern goes up by 8 each time: 33 + 8 = 41.
Q447: What is the fifth number in the pattern: 51, 58, 65, 72, ?
Answer: 79
💡 The pattern goes up by 7 each time: 72 + 7 = 79.
Q448: What is the fifth number in the pattern: 5, 13, 21, 29, ?
Answer: 37
💡 The pattern goes up by 8 each time: 29 + 8 = 37.
Q449: What is the fifth number in the pattern: 5, 11, 17, 23, ?
Answer: 29
💡 The pattern goes up by 6 each time: 23 + 6 = 29.
Q450: What is the fifth number in the pattern: 48, 57, 66, 75, ?
Answer: 84
💡 The pattern goes up by 9 each time: 75 + 9 = 84.
Q451: What is the fifth number in the pattern: 35, 41, 47, 53, ?
Answer: 59
💡 The pattern goes up by 6 each time: 53 + 6 = 59.
Q452: What is the fifth number in the pattern: 13, 19, 25, 31, ?
Answer: 37
💡 The pattern goes up by 6 each time: 31 + 6 = 37.
Q453: What is the fifth number in the pattern: 9, 11, 13, 15, ?
Answer: 17
💡 The pattern goes up by 2 each time: 15 + 2 = 17.
Q454: What is the fifth number in the pattern: 56, 66, 76, 86, ?
Answer: 96
💡 The pattern goes up by 10 each time: 86 + 10 = 96.
Q455: What is the fifth number in the pattern: 13, 17, 21, 25, ?
Answer: 29
💡 The pattern goes up by 4 each time: 25 + 4 = 29.
Q456: What is the fifth number in the pattern: 11, 19, 27, 35, ?
Answer: 43
💡 The pattern goes up by 8 each time: 35 + 8 = 43.
Q457: What is the fifth number in the pattern: 40, 52, 64, 76, ?
Answer: 88
💡 The pattern goes up by 12 each time: 76 + 12 = 88.
Q458: What is the fifth number in the pattern: 38, 45, 52, 59, ?
Answer: 66
💡 The pattern goes up by 7 each time: 59 + 7 = 66.
Q459: What is the fifth number in the pattern: 35, 38, 41, 44, ?
Answer: 47
💡 The pattern goes up by 3 each time: 44 + 3 = 47.
Q460: What is the fifth number in the pattern: 48, 58, 68, 78, ?
Answer: 88
💡 The pattern goes up by 10 each time: 78 + 10 = 88.
Q461: What is the fifth number in the pattern: 44, 47, 50, 53, ?
Answer: 56
💡 The pattern goes up by 3 each time: 53 + 3 = 56.
Q462: What is the fifth number in the pattern: 39, 46, 53, 60, ?
Answer: 67
💡 The pattern goes up by 7 each time: 60 + 7 = 67.
Q463: What is the fifth number in the pattern: 7, 19, 31, 43, ?
Answer: 55
💡 The pattern goes up by 12 each time: 43 + 12 = 55.
Q464: What is the fifth number in the pattern: 28, 37, 46, 55, ?
Answer: 64
💡 The pattern goes up by 9 each time: 55 + 9 = 64.
Q465: What is the fifth number in the pattern: 52, 57, 62, 67, ?
Answer: 72
💡 The pattern goes up by 5 each time: 67 + 5 = 72.
Q466: What is the fifth number in the pattern: 42, 45, 48, 51, ?
Answer: 54
💡 The pattern goes up by 3 each time: 51 + 3 = 54.
Q467: What is the fifth number in the pattern: 55, 57, 59, 61, ?
Answer: 63
💡 The pattern goes up by 2 each time: 61 + 2 = 63.
Q468: What is the fifth number in the pattern: 57, 65, 73, 81, ?
Answer: 89
💡 The pattern goes up by 8 each time: 81 + 8 = 89.
Q469: What is the fifth number in the pattern: 11, 15, 19, 23, ?
Answer: 27
💡 The pattern goes up by 4 each time: 23 + 4 = 27.
Q470: What is the fifth number in the pattern: 44, 46, 48, 50, ?
Answer: 52
💡 The pattern goes up by 2 each time: 50 + 2 = 52.
Q471: What is the fifth number in the pattern: 8, 17, 26, 35, ?
Answer: 44
💡 The pattern goes up by 9 each time: 35 + 9 = 44.
Q472: What is the fifth number in the pattern: 9, 15, 21, 27, ?
Answer: 33
💡 The pattern goes up by 6 each time: 27 + 6 = 33.
Q473: What is the fifth number in the pattern: 52, 61, 70, 79, ?
Answer: 88
💡 The pattern goes up by 9 each time: 79 + 9 = 88.
Q474: What is the fifth number in the pattern: 59, 65, 71, 77, ?
Answer: 83
💡 The pattern goes up by 6 each time: 77 + 6 = 83.
Q475: What is the fifth number in the pattern: 39, 42, 45, 48, ?
Answer: 51
💡 The pattern goes up by 3 each time: 48 + 3 = 51.
Q476: What is the fifth number in the pattern: 4, 7, 10, 13, ?
Answer: 16
💡 The pattern goes up by 3 each time: 13 + 3 = 16.
Q477: What is the fifth number in the pattern: 32, 35, 38, 41, ?
Answer: 44
💡 The pattern goes up by 3 each time: 41 + 3 = 44.
Q478: What is the fifth number in the pattern: 57, 63, 69, 75, ?
Answer: 81
💡 The pattern goes up by 6 each time: 75 + 6 = 81.
Q479: What is the fifth number in the pattern: 26, 28, 30, 32, ?
Answer: 34
💡 The pattern goes up by 2 each time: 32 + 2 = 34.
Q480: What is the fifth number in the pattern: 31, 42, 53, 64, ?
Answer: 75
💡 The pattern goes up by 11 each time: 64 + 11 = 75.
Q481: What is the fifth number in the pattern: 33, 44, 55, 66, ?
Answer: 77
💡 The pattern goes up by 11 each time: 66 + 11 = 77.
Q482: What is the fifth number in the pattern: 1, 7, 13, 19, ?
Answer: 25
💡 The pattern goes up by 6 each time: 19 + 6 = 25.
Q483: What is the fifth number in the pattern: 32, 40, 48, 56, ?
Answer: 64
💡 The pattern goes up by 8 each time: 56 + 8 = 64.
Q484: What is the fifth number in the pattern: 36, 43, 50, 57, ?
Answer: 64
💡 The pattern goes up by 7 each time: 57 + 7 = 64.
Q485: What is the fifth number in the pattern: 56, 58, 60, 62, ?
Answer: 64
💡 The pattern goes up by 2 each time: 62 + 2 = 64.
Q486: What is the fifth number in the pattern: 9, 12, 15, 18, ?
Answer: 21
💡 The pattern goes up by 3 each time: 18 + 3 = 21.
Q487: What is the fifth number in the pattern: 60, 71, 82, 93, ?
Answer: 104
💡 The pattern goes up by 11 each time: 93 + 11 = 104.
Q488: What is the fifth number in the pattern: 28, 40, 52, 64, ?
Answer: 76
💡 The pattern goes up by 12 each time: 64 + 12 = 76.
Q489: What is the fifth number in the pattern: 35, 37, 39, 41, ?
Answer: 43
💡 The pattern goes up by 2 each time: 41 + 2 = 43.
Q490: What is the fifth number in the pattern: 25, 32, 39, 46, ?
Answer: 53
💡 The pattern goes up by 7 each time: 46 + 7 = 53.
Q491: What is the fifth number in the pattern: 22, 33, 44, 55, ?
Answer: 66
💡 The pattern goes up by 11 each time: 55 + 11 = 66.
Q492: What is the fifth number in the pattern: 24, 29, 34, 39, ?
Answer: 44
💡 The pattern goes up by 5 each time: 39 + 5 = 44.
Q493: What is the fifth number in the pattern: 28, 34, 40, 46, ?
Answer: 52
💡 The pattern goes up by 6 each time: 46 + 6 = 52.
Q494: What is the fifth number in the pattern: 14, 19, 24, 29, ?
Answer: 34
💡 The pattern goes up by 5 each time: 29 + 5 = 34.
Q495: What is the fifth number in the pattern: 25, 35, 45, 55, ?
Answer: 65
💡 The pattern goes up by 10 each time: 55 + 10 = 65.
Q496: What is the fifth number in the pattern: 15, 19, 23, 27, ?
Answer: 31
💡 The pattern goes up by 4 each time: 27 + 4 = 31.
Q497: What is the fifth number in the pattern: 58, 63, 68, 73, ?
Answer: 78
💡 The pattern goes up by 5 each time: 73 + 5 = 78.
Q498: What is the fifth number in the pattern: 13, 16, 19, 22, ?
Answer: 25
💡 The pattern goes up by 3 each time: 22 + 3 = 25.
Q499: What is the fifth number in the pattern: 25, 31, 37, 43, ?
Answer: 49
💡 The pattern goes up by 6 each time: 43 + 6 = 49.
Q500: What is the fifth number in the pattern: 6, 17, 28, 39, ?
Answer: 50
💡 The pattern goes up by 11 each time: 39 + 11 = 50.