# Order and compare objects by mass

Lesson

## What is mass?

When we think about how heavy something is, we are thinking about its mass. We use units of measurement to describe the mass of objects, such as:

• milligrams
• grams, and
• kilograms.

When we need to follow a recipe, kitchen scales  help us weigh ingredients. We can stand on a set of scales to find our weight in kilograms.

Remember!

To put objects in order by mass, we need to make sure we are using the same unit of measurement, such as grams, for each object we are comparing.

We could weigh each object in a group to put them in order but we could also use balance scales. We can work out which object is heavier or lighter out of two objects, then compare it to another object.

In the video, we'll use the mass to compare objects, as well as balance scales.

#### Worked examples

##### question 1

We want to order these animals from heaviest to lightest.

 Cockatoo Sparrow Pigeon
1. Which of these animals is the heaviest?

Sparrow

A

Cockatoo

B

Pigeon

C

Sparrow

A

Cockatoo

B

Pigeon

C
2. Which of these animals is the second heaviest?

Sparrow

A

Cockatoo

B

Pigeon

C

Sparrow

A

Cockatoo

B

Pigeon

C
3. Which of these animals is the lightest?

Sparrow

A

Pigeon

B

Cockatoo

C

Sparrow

A

Pigeon

B

Cockatoo

C

##### Question 2

We want to order these animals according to their mass from heaviest to lightest.

1. Which of these animals is heavier? (The pigeon is on the left.)

cockatoo

A

pigeon

B

cockatoo

A

pigeon

B
2. Which of these animals is heavier? (The sparrow is on the left.)

sparrow

A

pigeon

B

sparrow

A

pigeon

B
3. The animals weights in decreasing order is:

sparrow, pigeon, cockatoo

A

cockatoo, pigeon, sparrow

B

sparrow, cockatoo, pigeon

C

cockatoo, sparrow, pigeon

D

sparrow, pigeon, cockatoo

A

cockatoo, pigeon, sparrow

B

sparrow, cockatoo, pigeon

C

cockatoo, sparrow, pigeon

D

##### Question 3

A pelican weighs $12$12 kg, a turkey weighs $35$35 kg, a chicken weighs $3$3 kg and an ostrich weighs $111$111 kg.

1. Choose the list that puts these birds in order from lightest to heaviest.

chicken, turkey, ostrich, pelican

A

chicken, pelican, turkey, ostrich

B

turkey, pelican, chicken, ostrich

C

ostrich, turkey, pelican, chicken

D

chicken, turkey, ostrich, pelican

A

chicken, pelican, turkey, ostrich

B

turkey, pelican, chicken, ostrich

C

ostrich, turkey, pelican, chicken

D