 # Understand Mass, Weight and Gravity

In this worksheet, students will learn the definition of mass, how it differs from weight and the effect of the gravitational force of Earth is investigated. Key stage:  KS 4

Difficulty level:   ### QUESTION 1 of 10

Ever thought about how much you weight? What if I told you you could lose weight by gonig into space - in fact, you would weigh nothing at all if you were in space. Want to put on weight? Why not just take a trip to Jupiter - you would weight 23 times more than you weigh on the earth! Trouble is that when you get back to the earth, your weight will be back to normal, so it's not a quick way to get hench... There is obviously something weird going on here, and it is with the use of the word weight. in science, it doesn't mean what you think it means - let's take a look at it in more detail.

Mass is the amount of matter in an object. Weight is a force acting on that matter. Weight is the result of gravity that attracts objects towards the centre of the Earth.

The strength of the weight as a force depends on the strength of the gravitational field around the Earth and other planets. The formula that shows the relation between mass, weight and gravitational field strength is:

weight  =  mass  ×  gravitational field strength

Weight is measured in Newton (N), mass in kg and the gravitational field strength on Earth is 10 N/kg. On the Moon it is only 1.6 N/kg.

Gravity is very important, because it keeps the Earth's atmosphere in place, it secures the orbit of the planets around the Sun and keeps galaxies together. Tide is a result of gravitational pull between the Earth and the Moon, as you can see on this diagram. Black holes have an extremely high gravitational pull, so nothing can escape them. Choose the right definition of mass.

The strength of gravity in an object

The amount of matter in an object

How heavy an object is

What is weight?

Write one word.

Why is there such a force as weight?

Because of Earth's magnetic field

Because of mass

Because of gravity

Calculate the weight of a 1 kg book on Earth.

1 N

10 N

100 N

Calculate the weight of the same 1 kg book on the Moon.

1.6 N

1.6 kg

1.6 N/kg

Calculate the mass of an object if its weight on Earth is 100 N.

1000 kg

100 kg

10 kg

What is the gravitational field of planet X if a 100 kg object weighs 5000 N there?

500 000 N/kg

500 N/kg

50 N/kg

Name a phenomenon that occurs due to gravity on Earth.

Write one word.

Name a phenomenon that occurs in space due to gravity.

Write two words.

How is gravity vital to life on Earth?

We can not escape Earth.

The atmosphere stays in its place.

Gravity keeps galaxies together.

• Question 1

Choose the right definition of mass.

The amount of matter in an object
EDDIE SAYS
Mass is the amount of matter in an object. Mass doesn't change no matter where you are.
• Question 2

What is weight?

Write one word.

force
forces
EDDIE SAYS
Weight is a force. it depends on how much gravity is pulling your mass down, so in sapce, it is 0 and on Jupiter, it is 23 times what it is on earth.
• Question 3

Why is there such a force as weight?

Because of gravity
EDDIE SAYS
Weight is the result of gravity. It is how much gravity is pulling you into the object that you are using to weight yourself.
• Question 4

Calculate the weight of a 1 kg book on Earth.

10 N
EDDIE SAYS
weight = mass x Earth's gravitational field strength
= 1 x 10 = 10 N
• Question 5

Calculate the weight of the same 1 kg book on the Moon.

1.6 N
EDDIE SAYS
weight = mass x Moon's gravitational field strength
= 1 x 1.6 = 1.6 N
• Question 6

Calculate the mass of an object if its weight on Earth is 100 N.

10 kg
EDDIE SAYS
weight = mass x Earth's gravitational field strength (g)
mass = weight / g = 100 / 10 =10 kg
• Question 7

What is the gravitational field of planet X if a 100 kg object weighs 5000 N there?

50 N/kg
EDDIE SAYS
weight = mass x gravitational field strength (g)
g = weight / mass = 5000 / 100 = 50 N/kg
• Question 8

Name a phenomenon that occurs due to gravity on Earth.

Write one word.

tide
tides
EDDIE SAYS
Tides are the result of the gravitational pull between Earth and Moon. The moon pulls the seas up and that makes the high and low tides. When the moon lets the sea go it is in between.
• Question 9

Name a phenomenon that occurs in space due to gravity.

Write two words.

Black hole
Black holes
EDDIE SAYS
Black holes have an extreme gravitational pull; therefore, nothing can escape them. We have only just been able to photograph them because not even light can escape them - hence the term black.
• Question 10

How is gravity vital to life on Earth?

The atmosphere stays in its place.
EDDIE SAYS
Gravity is vital to life on Earth because it keeps the atmosphere in its place. No gravity, no atmosphere, no oxygen, no life.
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