8. Measurement

Lesson

Think about a feather and an elephant. Which one of those items do you think would be heavier?

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

Which unit is best to measure the mass of this cup of flour?

A

Kilograms

B

Grams

Worked Solution

Idea summary

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.

This video looks at measuring the mass of objects using a scale. Key considerations are how to identify the scale used and how it is similar to a number line.

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

Idea summary

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

We may not always need to know the exact mass of an object, especially if we can compare our object to other objects. This video looks at objects using grams (g) and kilograms (kg).

Choose the best estimate for the mass of baby.

A

45 \text{ kg}

B

95 \text{ kg}

C

25 \text{ kg}

D

2 \text{ kg}

Worked Solution

Idea summary

A gram has a mass similar to a piece of paper, or a feather.

A kilogram has a mass similar to a 1 litre bottle of milk or juice.