10 questions · Four answers, and only one is true. Can you spot it?
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Question 1 of 10
How does a light bulb work?
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The old kind heats a thin wire fiercely; an LED simply shines.
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A fire needs air, and the inside of a bulb has almost none.
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Plain glass makes no light at all — look at a window.
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A bulb kept in a dark cupboard lights up perfectly well.
Show the answer
- A The old kind heats a thin wire fiercely; an LED simply shines.
- B A fire needs air, and the inside of a bulb has almost none.
- C Plain glass makes no light at all — look at a window.
- D A bulb kept in a dark cupboard lights up perfectly well.
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Question 2 of 10
How does a clock tell the time?
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A clock keeps the same time whether we are tired or not.
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Gears turn the count into hands — a swinging pendulum, or a tiny crystal shivering where you cannot see it.
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The hands are turned by the clock itself, tick after tick.
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A sundial does; a clock works just as well indoors at night.
Show the answer
- A A clock keeps the same time whether we are tired or not.
- B Gears turn the count into hands — a swinging pendulum, or a tiny crystal shivering where you cannot see it.
- C The hands are turned by the clock itself, tick after tick.
- D A sundial does; a clock works just as well indoors at night.
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Question 3 of 10
How does a phone let us talk to someone far away?
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No voice carries across an ocean.
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Nothing of your breath leaves the room.
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It races away and becomes sound again at the other end, down cables, close to the speed of light.
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You hear the reply straight away, with no waiting.
Show the answer
- A No voice carries across an ocean.
- B Nothing of your breath leaves the room.
- C It races away and becomes sound again at the other end, down cables, close to the speed of light.
- D You hear the reply straight away, with no waiting.
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Question 4 of 10
How does the internet work?
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There is no single one — that is what makes it a web.
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Messages travel in small pieces to a computer waiting to help, called a server, and it answers in under a second.
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Switch off the connection and almost none of it is there.
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Most of the journey is through cables, many of them under the sea.
Show the answer
- A There is no single one — that is what makes it a web.
- B Messages travel in small pieces to a computer waiting to help, called a server, and it answers in under a second.
- C Switch off the connection and almost none of it is there.
- D Most of the journey is through cables, many of them under the sea.
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Question 5 of 10
How does a zip work?
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Nothing sticks — the teeth hold each other.
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Plenty of zips are plastic, with no metal in them at all.
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Going down, the same clever shape prises them apart again.
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They would only work once if they did.
Show the answer
- A Nothing sticks — the teeth hold each other.
- B Plenty of zips are plastic, with no metal in them at all.
- C Going down, the same clever shape prises them apart again.
- D They would only work once if they did.
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Question 6 of 10
How does a train stay on the track?
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Most trains use no magnets at all; the shape does the work.
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There is no steering wheel in a train's cab.
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Heavy things slide off rails just as easily.
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Their cone shape does the steering; a train cannot steer itself at all.
Show the answer
- A Most trains use no magnets at all; the shape does the work.
- B There is no steering wheel in a train's cab.
- C Heavy things slide off rails just as easily.
- D Their cone shape does the steering; a train cannot steer itself at all.
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Question 7 of 10
How do magnets work?
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Try one on an aluminium can or a copper coin: nothing happens.
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It works on other magnets too, either way: put two of the same ends together and they push apart.
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Wash a magnet and it sticks just as well — and only to certain metals.
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Air has nothing to do with it; a magnet works in space too.
Show the answer
- A Try one on an aluminium can or a copper coin: nothing happens.
- B It works on other magnets too, either way: put two of the same ends together and they push apart.
- C Wash a magnet and it sticks just as well — and only to certain metals.
- D Air has nothing to do with it; a magnet works in space too.
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Question 8 of 10
How does a fridge keep food cold?
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And lets it go into the room — there is no such thing as making cold.
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A fridge stays cold in the middle of a heatwave.
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Cold is simply what is left when heat has gone.
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The air in a fridge is chilly, not frozen — the milk would be a block of ice.
Show the answer
- A And lets it go into the room — there is no such thing as making cold.
- B A fridge stays cold in the middle of a heatwave.
- C Cold is simply what is left when heat has gone.
- D The air in a fridge is chilly, not frozen — the milk would be a block of ice.
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Question 9 of 10
How does a car move?
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A car climbs hills too, and drives on the flat.
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A car drives straight into the wind just as well.
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The tyres grip the road on a patch about the size of your hand — enough for the whole car.
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The road stays perfectly still; it only offers grip.
Show the answer
- A A car climbs hills too, and drives on the flat.
- 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 The road stays perfectly still; it only offers grip.
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Question 10 of 10
How does an airplane fly?
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Weight is exactly the same up there; the wings are what hold it.
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The engines supply the speed, and that upward push is called lift.
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A plane's wings never move — the engines do the work instead.
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That is a balloon; a plane is far heavier than the air around it.
Show the answer
- A Weight is exactly the same up there; the wings are what hold it.
- B The engines supply the speed, and that upward push is called lift.
- C A plane's wings never move — the engines do the work instead.
- D That is a balloon; a plane is far heavier than the air around it.
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