Measuring, Estimating and Units

Hong Kong

Stage 1 - Stage 3

Lesson

You may have learned about measuring quantities and estimating capacities, ordering objects by their capacity, or comparing objects using capacity.

Now we will review each of these topics.

We can measure quantities using containers with measurement scales. This means we can work out the exact amount in a container by reading the scale. Watch this video to learn about reading measurement scales.

Try this question for yourself.

What is the volume of water contained in the measuring cylinder?

We can compare objects by different measurement attributes such as, length, height, weight or capacity.

First, we make sure the objects are in the same measurement unit, for example, metres. Then, we can compare their value. Watch this video to learn more about comparing objects.

Try this question for yourself.

A polar bear is $2.0$2.0m long. A brown bear is $2.5$2.5m long.

Which animal is longer?

Polar Bear

ABrown Bear

B

We can use comparisons of objects to estimate the size of different attributes. For example, if we know an elephant weighs $5000$5000 kilograms, we might estimate a rhinoceros weighs $2500$2500 kilograms as it is approximately half the size.

You may have learned about fractions before. Now watch this video to learn more about estimating measurements, some strategies use our fraction knowledge.

Now try these questions for yourself.

Container B has a capacity of $5$5 L.

Container B $=$= $5$5 L |

Estimate the capacity of container A.

$10$10 L

A$1$1 L

B$15$15 L

C$5$5 L

D

An elephant has a mass of $5000$5000 kg.

An elephant = $5000$5000 kg |

Estimate the mass of a rhinoceros:

$2500$2500 kg

A$7$7 kg

B$6000$6000 kg

C$2500$2500 g

D

We can use measurement tools to evaluate attributes. First, we check the measurement unit, then we read the results.

It is also important for us to interpret what the values mean. For example, if one person is $160$160 cm tall and another is $170$170 cm, halfway between them would be $165$165 cm.

Sometimes we use multiplication to help us interpret measurements. You may have learned about multiplication before. Now watch this video to learn more about measuring and interpreting results.

Now try these questions for yourself.

The scale below shows an object balanced evenly with a particular weight.

The following weights were on the scale:

What is the total mass of the object?

Here is a list of the long jump results from a school athletics carnival.

Whose jump was closest to $1$1 metre?

Name | Distance (m) |
---|---|

Mim | $0.85$0.85 |

Sam | $1.08$1.08 |

George | $1.44$1.44 |

Grace | $0.96$0.96 |

Grace

ASam

BGeorge

CMim

D

Remember!

A measurement can be used to communicate different attributes, such as length, capacity or weight.

We can use known measurements to estimate or compare objects.