Gravity 2

In this worksheet, students will be helped to take a slightly deeper look at what the force of gravity is all about: how it is measured and how it would be affected on different planets.

Key stage:  KS 2

Curriculum topic:   Forces

Curriculum subtopic:   Gravity

Difficulty level:

QUESTION 1 of 10

Gravity is a force that you will experience all your life: it stems from the fact that planet Earth is so massive compared to the objects on its surface, so it exerts a fairly big force on us, ensuring that we don't just float off into space!

Let's delve down into gravity!

Gravity is a force that pulls all objects on our planet towards the centre of the Earth. This causes objects to have what?

weight

heaviness

pull

Which of the following could you NOT use to measure the pull of gravity on an object?

forcemeter

kitchen scales

thermometer

A group of young scientists were finding out how much gravity acted on different objects. Here is a zoomed-in picture of what the reading was for a clock.

How much do you think it weighs?

5N

5.5N

6N

Here is what the reading looked like for a pair of scissors.

What do you think the reading is?

1.5N

1.75N

2N

On the Moon the force of gravity is about 1/6 of what it is on Earth, so everything weighs less.

Why do you think this is so?

the Moon is smaller than the Earth

the Moon has no air

the Moon has no gravity

If you were able to walk on the Moon, with its lower gravity, would you feel you were...

heavier than on Earth

lighter than on Earth

the same as on Earth

Remembering that gravity on the Moon is 1/6 of Earth's gravity, how much would a 60N school bag weigh on the Moon?

6N

10N

60N

Mars is another planet which is relatively close to Earth. It's gravity is 1/3 of Earth's gravity.

The Mars explorer Curiosity is exploring Mars.

If Curiosity weighed 3000N on Earth, how much do you think it would weigh on Mars?

300N

1000N

3000N

On planet Earth the seas have tides - the water goes up and down each day. That means that when you go to the beach for a swim it's important to know whether the tide's going in or out.

What do you think causes the tides to go up and down?

magnetic pull of the Sun

rotation of the Earth

gravitational pull of the Moon

Which of the following things in your bathroom depend on gravity to work properly (tick all those you think do):

bath

toilet

toothbrush

bathmat

soap

shower

bath plug

plastic duck

• Question 1

Gravity is a force that pulls all objects on our planet towards the centre of the Earth. This causes objects to have what?

weight
EDDIE SAYS
'Weight' is the term used for the pull of gravity on the 'mass' of an object; mass simply means how much 'stuff' the object has in it, for example a large bulldozer has a lot more 'stuff'/mass than your bike. So the pull of Earth's gravity causes an object to weigh something (that's why it's weightless in space - it's not being pulled anywhere as there's no gravity).
• Question 2

Which of the following could you NOT use to measure the pull of gravity on an object?

thermometer
EDDIE SAYS
Both forcemeters and kitchen scales can weigh things, so they're measuring the pull of gravity. A thermometer measures temperature!
• Question 3

A group of young scientists were finding out how much gravity acted on different objects. Here is a zoomed-in picture of what the reading was for a clock.

How much do you think it weighs?

5.5N
EDDIE SAYS
Look at the pointer: it's between 5N and 6N but closest to the mark in between (5.5N), so that's the answer.
• Question 4

Here is what the reading looked like for a pair of scissors.

What do you think the reading is?

1.75N
EDDIE SAYS
Looking at the pointer it's more than 1.5N but less than 2N; in fact it's quite close the mark between them - that's 1.75N.
• Question 5

On the Moon the force of gravity is about 1/6 of what it is on Earth, so everything weighs less.

Why do you think this is so?

the Moon is smaller than the Earth
EDDIE SAYS
Lots of people think that there's no gravity on the Moon ... well, there is but it's much less because the Moon is smaller. It's not really tiny - in fact it's massive compared to you - but it's smaller size creates a smaller pull on objects on its surface so they weigh less.
• Question 6

If you were able to walk on the Moon, with its lower gravity, would you feel you were...

lighter than on Earth
EDDIE SAYS
Since the Moon is smaller it has a smaller pull on you which means you weigh less, so you'd feel lighter and it'd be weird walking as you'd have to skip along rather than walk!
• Question 7

Remembering that gravity on the Moon is 1/6 of Earth's gravity, how much would a 60N school bag weigh on the Moon?

10N
EDDIE SAYS
To work this out it's 1/6 of 60 which is 10N; in other words it's 60÷6=10.
• Question 8

Mars is another planet which is relatively close to Earth. It's gravity is 1/3 of Earth's gravity.

The Mars explorer Curiosity is exploring Mars.

If Curiosity weighed 3000N on Earth, how much do you think it would weigh on Mars?

1000N
EDDIE SAYS
Mars's gravity is 1/3 of Earth's so 1/3 of 3000N is 1000N, or 3000÷3=1000.
• Question 9

On planet Earth the seas have tides - the water goes up and down each day. That means that when you go to the beach for a swim it's important to know whether the tide's going in or out.

What do you think causes the tides to go up and down?

gravitational pull of the Moon
EDDIE SAYS
Amazingly the size of the Moon has a big influence on the Earth: its gravitational pull 'lifts' the seas a little as the Earth spins so that as it goes around different parts of the world experience more water or less water, which means that the tide's going up or down/in or out.
• Question 10

Which of the following things in your bathroom depend on gravity to work properly (tick all those you think do):

bath
toilet
bathmat
shower
bath plug
plastic duck
EDDIE SAYS
They pretty much all do! Your toothbrush doesn't rely on gravity to work and ordinary soap doesn't either (although a hand dispenser soap delivers liquid soap by gravity, so you can have that if you thought so!).
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