7. Measurement

Lesson

Can you find the mass of an object?

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 their weights are equal.

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

It is most appropriate to use milligrams to measure:

A

A pencil case

B

A pig

C

A small feather

Worked Solution

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.

selects and uses the appropriate unit and device to measure the masses of objects, and converts between units of mass