Comparing mass - KS1 Maths - Year 1

What is mass?

The mass of an object is how heavy it is.

The amount of matter in an object is its mass.

You can use the words 'heavy' and 'light' to describe the mass of an object.

You can use the words 'heavier' and 'lighter' when comparing the mass of objects.

You can find out the mass of an object using balance scales.

Quiz: Comparing mass

Why not see how much you know about this topic already? Then work through the page and see if you can beat your score.

Comparing objects

Let's compare the mass of some animals.

Look at this dog and bird.

A large, heavy dog sat next to a small, light bird.

If you are describing their mass you might say:

"The dog is heavy and the bird is light."

When you compare the mass of objects, you can use the words 'heavier' and 'heaviest, or 'lighter' and 'lightest'

Now look at these two animals.

A very large, heavy elephant stood next to a very small, light hedgehog.

If you are comparing them you might say:

"The elephant is heavier than the hedgehog".

Look, here comes a bee…

A bee and a hedgehog. The bee is flying around and the hedgehog looks cross.

If you are comparing the mass of these animals you might say:

"The bee is lighter than the hedgehog."

Which animal do you think is the heaviest of all?

A big elephant stood next to a small hedgehog. The hedgehog has a bee on their nose and looks cross.

The elephant is the heaviest, of course!

More than and less than

You can compare the mass of objects with symbols to show 'more than', 'less than' and 'is equal to'.

> is the symbol for 'more than'. < is the symbol for 'less than'. = is the symbol for equal to.

Now, let's use these symbols to compare the mass of some different things.

An apple, more than symbol and a strawberry.

"The mass of an apple is more than the mass of a strawberry."

A cat lying down with one eye open and one closed, a less than symbol and a big brown bear.

"The mass of a cat is less than the mass of a bear."

A book, an equal symbol and a bag of sugar.

"The mass of this book is equal to the mass of this bag of sugar."

Remember, an object can be heavier than something else, even if it looks smaller.

The mass of two objects might be equal, too.

Balance scales

You can use balance scales to compare the mass of objects.

Look at these scales. What do you think they are showing you?

Balance scales with a pencil on the left scale and a trainer shoe on the right scale which is hanging down lower than the left scale.

"The shoe is heavier than the pencil."

Or you could also say:

"The pencil is lighter than the shoe."

Now look at this set of scales. What is it showing you?

Balance scales with an apple in the left scale and a tennis ball in the right. The scales are balanced equally.

The scales are showing that the apple and the ball have the same mass because they are balanced.

So you could say:

"The mass of the apple is equal to the ball."

Example

You can use balance scales to compare the mass of objects and put them in order.

Look at these scales.

2 balance scales. The first has a banana in the left scale and the melon in the right which is hanging down lower than the banana. On the second scale the banana is on the left scale and hanging lower than the right with the orange in it.

Can you put these fruits in order from heaviest to lightest?