 # 7.10 Units of mass

Lesson

## Ideas

Can you  find the mass  of an object?

### Examples

#### Example 1

The scale below shows an object balanced evenly with a particular set of weights.

The following weights were on the scale:

What is the total mass of the object?

Worked Solution
Create a strategy

Find the total mass by adding all the values on the given weights.

Apply the idea

We can see there are one 5\text{ kg} weight, two 2\text{ kg} weights, and three 1 \text{ kg} weights.

Idea summary

When two items are balanced on a scale their weights are equal.

## Measure and estimate mass

This video introduces the units of milligrams, grams, and kilograms and discusses the types of objects that would be measured by these units.

### Examples

#### Example 2

It is most appropriate to use milligrams to measure:

A
A pencil case
B
A pig
C
A small feather
Worked Solution
Create a strategy

Choose the lightest object.

Apply the idea

Milligrams is used to measure very light objects like a small feather. The answer is option C.

Idea summary

The prefixes can help with identifying the size of the units.

milli - for one thousandth of a gram.

kilo - for one thousand of, so a kilogram has 1000 grams.

Milligrams are appropriate to measure tiny very light objects like a small feather and insects.

Grams are appropriate to measure small light objects like a pencil case or cup.

Kilograms are appropriate to measure heavy objects like people and bikes.

### Outcomes

#### VCMMG195

Choose appropriate units of measurement for length, area,volume, capacity and mass