Heavier or lighter?

You don't always need numbers — your hands can tell you.

Pick up two things at home. Which feels heavier? That is real, mathematical mass comparison.

For trickier pairs (like an orange vs. an apple), use a balance. Whichever side goes DOWN is heavier.

Standard units: grams & kilograms

When you need to be exact, you use standard units.

• g (grams) for small things. A paperclip is about 1 g.
• kg (kilograms) for bigger things. A bag of sugar is 1 kg.
• 1 kg = 1000 g. A LOT of paperclips!

Quick check: Which would you measure in kg — an apple, or a person?

Reading kitchen scales

A kitchen scale has numbers marked on a dial or screen. The needle (or the digital number) tells you the mass.

The trick: look at what each mark is worth. If the dial goes 0, 100, 200, 300… each mark is 100 g.

Some scales show kg. If it goes 0, 0.5, 1, 1.5, 2 — that's kilograms.

What is temperature?

Temperature is how hot or cold something is. We measure it in degrees Celsius — written °C.

Some useful temperatures to remember:

• 0 °C — water freezes (ice!)
• 20 °C — a warm classroom
• 37 °C — body temperature
• 100 °C — boiling water

Reading a thermometer

A thermometer looks like a tall ruler. The higher the red line goes, the hotter it is.

To read it: look at the number nearest the top of the red line.

If the line is at 20, it's 20 °C. If it's between 20 and 30, look carefully — is it closer to 20 or 30?

That's mass and temperature in a nutshell. Now go and try the worksheet!