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How Things Work

10 questions · Four answers, and only one is true. Can you spot it?

  1. Question 1 of 10

    How does a phone let us talk to someone far away?

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    • A No voice carries across an ocean.
    • B It races away and becomes sound again at the other end, down cables, close to the speed of light.
    • C Nothing of your breath leaves the room.
    • D You hear the reply straight away, with no waiting.

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  2. Question 2 of 10

    How do big ships float?

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    • A Switch the engines off and the ship still floats.
    • B A lump of steel dropped in the sea sinks straight away.
    • C So the water can push it up: shape a lump of steel into a bowl and the same steel floats.
    • D A ship floats perfectly still on a calm day.

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  3. Question 3 of 10

    How does an airplane fly?

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    • A The engines supply the speed, and that upward push is called lift.
    • B A plane's wings never move — the engines do the work instead.
    • C That is a balloon; a plane is far heavier than the air around it.
    • D Weight is exactly the same up there; the wings are what hold it.

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  4. Question 4 of 10

    How does a zip work?

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    • A They would only work once if they did.
    • B Plenty of zips are plastic, with no metal in them at all.
    • C Nothing sticks — the teeth hold each other.
    • D Going down, the same clever shape prises them apart again.

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  5. Question 5 of 10

    How does a fridge keep food cold?

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    • A The air in a fridge is chilly, not frozen — the milk would be a block of ice.
    • B A fridge stays cold in the middle of a heatwave.
    • C Cold is simply what is left when heat has gone.
    • D And lets it go into the room — there is no such thing as making cold.

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  6. Question 6 of 10

    How does a car move?

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    • A The road stays perfectly still; it only offers grip.
    • B A car drives straight into the wind just as well.
    • C The tyres grip the road on a patch about the size of your hand — enough for the whole car.
    • D A car climbs hills too, and drives on the flat.

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  7. Question 7 of 10

    How does a train stay on the track?

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    • A Heavy things slide off rails just as easily.
    • B Their cone shape does the steering; a train cannot steer itself at all.
    • C There is no steering wheel in a train's cab.
    • D Most trains use no magnets at all; the shape does the work.

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  8. Question 8 of 10

    How does a light bulb work?

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    • A Plain glass makes no light at all — look at a window.
    • B The old kind heats a thin wire fiercely; an LED simply shines.
    • C A fire needs air, and the inside of a bulb has almost none.
    • D A bulb kept in a dark cupboard lights up perfectly well.

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  9. Question 9 of 10

    What is electricity?

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    • A Electricity can make light, but it is not made of it.
    • B Power stations make it too — and so does a thundercloud.
    • C Nothing is poured, and nothing leaks out of a cut wire.
    • D They only flow when the loop is closed, and that is what a switch opens and shuts.

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  10. Question 10 of 10

    How does a clock tell the time?

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    • A The hands are turned by the clock itself, tick after tick.
    • B Gears turn the count into hands — a swinging pendulum, or a tiny crystal shivering where you cannot see it.
    • C A clock keeps the same time whether we are tired or not.
    • D A sundial does; a clock works just as well indoors at night.

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