Year 2 · Mass, capacity and temperature
Say which of 2 things is heavier
Learn how to say which thing is heavier, which container holds more, how to add and subtract amounts of liquid, and how to read a thermometer.
Definition
Things can be heavy or light. A container can hold a lot or a little, and how much it holds is called its capacity. A thermometer tells us how hot or cold something is. We measure with grams and kilograms, litres and millilitres, and degrees.
Why Do I Have to Learn This?
Area measures how much surface a shape covers. It tells you how much paint, carpet or wrapping paper you need.
Key Rules:
- 1. On a balance, the heavier thing sinks down and the lighter thing rises up.
- 2. To compare two amounts, use the same unit and pick the bigger number.
Remember:
- •Use the same units to compare. Add liquid in, subtract liquid out, and read every scale like a number line.
Don’t Forget...
- •Thinking the bigger object is always the heavier one. Size and mass are different things: a big balloon can be lighter than a small stone. The balance tells you which is heavier, not the size.
Area
The amount of surface a flat shape covers. For a rectangle, area = length × width.
A rectangle 4 cm by 3 cm has an area of 12 cm².
Worked Example:
A jug has 300 ml of water in it. Ben pours in 200 ml more, then he pours 100 ml out. How much water is in the jug now?
Start with the 300 ml already in the jug.
Pouring in makes more, so add: 300 + 200 = 500.
Pouring out makes less, so subtract: 500 - 100 = 400.
Answer: 400 ml
Why It Works:
Grams, millilitres and degrees are equal-sized units, so amounts measured in them behave just like numbers. Pouring in puts more millilitres together, so adding gives the real total, and pouring out takes millilitres away, so subtracting gives what is left. A thermometer scale is a number line, so equal jumps in temperature take equal spaces on the tube.
Another Example:
A thermometer is marked 0, 10 and 20 degrees. Between each pair of numbers there are 5 small steps, so each small step is worth 2 degrees. The red line stops 2 small steps above 10. What is the temperature?
Start at the 10 mark.
Each small step is worth 2 degrees.
Count on 2 steps from 10: 12, then 14.
Answer: 14 degrees
Animated Example:
Free Say which of 2 things is heavier Worksheet
Download free worksheets and practise today.
Every download has a fresh set of questions.
Before this: Mass and volume (Year 1) · Next: Mass and capacity (Year 3)
Let’s Practise the Concept
Step 1 of 3
Put them in order
Tap the numbers from smallest to largest.
In order so far: nothing yet