## MEASUREMENTS

Measurements are important in **science**.
We use standard units to **measure objects**.
**Standard** means that everyone uses the same units of measurement.
There are many different **instruments** for measuring objects.

- Length - metre (m)
- Weight - gram( g)
- Volume - litre (l)
- Temperature - degree (
^{o})
- Time - second (s)

To measure length we use **millimetres** (mm), **centimetres** (cm), **metres** (m) and **kilometres** (km).
We measure lengths with a **ruler, metre rod or measuring tape**.

- 10 millimetres = 1 centimetre
- 100 centimetres = 1 metre
- 1000 metres = 1 kilometre

In the early days people looked at the **position of the sun** in the sky and the **length of shadows** to tell time.
Now we use **clocks and watches**.
Time is measured in **seconds** (s), **minutes** (m) and **hours** (h).

- 60 seconds = 1 minute
- 60 minutes = 1 hour
- 24 hours = 1 day

Weight is measured in **grams** (g) and **kilograms** (kg).
We measure weights with a **weighing machine**.

- 1000 grams = 1 kilogram
- 1000 kilograms = 1 tonne

We measure the **volume of liquids** such as water, petrol, milk and oil in **millilitres** (ml) and **litres** (l).
Liquids are measured using jars or beakers.
We can also measure the **volume of solids**.
The volume of solids is measured in **cubic meters** (m^{3}).

- 1000 millilitres = 1 litre

We measure how hot or how cold something is.
We do this by measuring **temperature** with a **thermometer**.
There are different kinds of thermometers.
A **clinical thermometer** is used to measure the temperature of the **human body**.
Temperature is measured in **degrees Celsius** (^{o}C) or **degrees Fahrenheit** (^{o}F).