9.06 Measure and estimate mass

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.

Examples

Example 1

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

A

Kilograms

B

Grams

Worked Solution

Create a strategy

Remember that 1 kilogram is equal to 1000 grams.

Think about these examples to help you.

Object	Best unit
Bar of chocolate	Grams
Person	Kilograms

Apply the idea

A cup of flour is small and light like a bar of chocolate.

So the correct answer is B: Grams.

Watch question walkthrough

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.

Examples

Example 2

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 is one 5\text{ kg} weight, two 2\text{ kg} weights and three 1 \text{ kg} weights.

\displaystyle \text{Object}	\displaystyle =	\displaystyle 5+2+2+1+1+1	Add the values
	\displaystyle =	\displaystyle 5 + 4 + 3	Add the 2s and 1s
	\displaystyle =	\displaystyle 12 \text{ kg}	Add the values

Watch question walkthrough

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).

Examples