Year 2: Degrees Celsius
Part of the Year 2 length, mass, capacity and temperature chapter. Chapter overview · whole chapter on one page
Degrees Celsius
A thermometer shows how hot or cold something is.
We measure temperature in degrees Celsius. We write it as °C.
Read the number at the top of the red line.
A higher number is hotter. A lower number is colder.
Key ideas
- A thermometer shows temperature.
- Temperature is measured in °C.
- A higher number is hotter. A lower number is colder.
- Read the top of the red line.
Method. Find the top of the red line. Count up from the nearest numbered mark.
- Find the top of the red liquid. The red line stops at this mark.top of the red line
- Count from the nearest number. Each small mark is one degree.10 + 8 = 18
- Write the answer. 18
Check. Count the small marks from 10 up to the red line: 8. ✓
Watch out. Read the top of the red liquid, not the bottom of the bulb.
Method. Change to the same unit, then pick the biggest amount.
- Look at A. A is 25 °C.A: 25 °C
- Look at B. B is 19 °C.B: 19 °C
- Pick the one with the biggest amount. Once the units match, the numbers can be compared.A wins
- Write the answer. A
Check. Compare the other amounts too. ✓
Watch out. Read the units first. 2 m is longer than 150 cm, because 2 m = 200 cm.
Method. Find the difference by taking the smaller amount away from the bigger one.
- Find the bigger amount. The bigger temperature is 20 °C.20 °C
- Find the smaller amount. The smaller temperature is 12 °C.12 °C
- Take the smaller amount away. Subtract to find the difference.20 − 12 = 8
- Write the answer. 8
Check. Add the difference back: 12 + 8 = 20. ✓
Watch out. Start with the bigger number, then take the smaller one away.
Watch out
Watch out: read the red line, not the bottom of the bulb.
Each small mark is one degree.
Exam tip
Grown-up tip. Put a thermometer in a glass of warm water. Ask: “Is it hotter or colder than the room?”
Exercise 5D Reading and comparing temperatures
Non-calculatorMethod. Find the top of the red line. Count up from the nearest numbered mark.
- Find the top of the red liquid. The red line stops at this mark.top of the red line
- Count from the nearest number. Each small mark is one degree.10 + 4 = 14
- Write the answer. 14
Check. Count the small marks from 10 up to the red line: 4. ✓
Watch out. Read the top of the red liquid, not the bottom of the bulb.
Method. Find the top of the red line. Count up from the nearest numbered mark.
- Find the top of the red liquid. The red line stops at this mark.top of the red line
- Count from the nearest number. Each small mark is one degree.30
- Write the answer. 30
Check. Count the small marks from 30 up to the red line: 0. ✓
Watch out. Read the top of the red liquid, not the bottom of the bulb.
Method. Find the top of the red line. Count up from the nearest numbered mark.
- Find the top of the red liquid. The red line stops at this mark.top of the red line
- Count from the nearest number. Each small mark is one degree.0 + 7 = 7
- Write the answer. 7
Check. Count the small marks from 0 up to the red line: 7. ✓
Watch out. Read the top of the red liquid, not the bottom of the bulb.
Method. Change to the same unit, then pick the biggest amount.
- Look at A. A is 22 °C.A: 22 °C
- Look at B. B is 17 °C.B: 17 °C
- Pick the one with the biggest amount. Once the units match, the numbers can be compared.A wins
- Write the answer. A
Check. Compare the other amounts too. ✓
Watch out. Read the units first. 2 m is longer than 150 cm, because 2 m = 200 cm.
Method. Change to the same unit, then pick the smallest amount.
- Look at A. A is 4 °C.A: 4 °C
- Look at B. B is 40 °C.B: 40 °C
- Pick the one with the smallest amount. Once the units match, the numbers can be compared.A wins
- Write the answer. A
Check. Compare the other amounts too. ✓
Watch out. Read the units first. 2 m is longer than 150 cm, because 2 m = 200 cm.
Method. Change to one unit, then put the smallest amount first.
- Look at A. A is 10 °C.A: 10 °C
- Look at C. C is 20 °C.C: 20 °C
- Look at B. B is 35 °C.B: 35 °C
- Put the amounts in order. Smallest firstA, C, B
- Write the letters. A, C, B
Check. Check each pair: the first is never bigger than the next. ✓
Watch out. Compare the numbers after you change to the same unit.
Method. Find the difference by taking the smaller amount away from the bigger one.
- Find the bigger amount. The bigger temperature is 19 °C.19 °C
- Find the smaller amount. The smaller temperature is 12 °C.12 °C
- Take the smaller amount away. Subtract to find the difference.19 − 12 = 7
- Write the answer. 7
Check. Add the difference back: 12 + 7 = 19. ✓
Watch out. Start with the bigger number, then take the smaller one away.
Method. Find the difference by taking the smaller amount away from the bigger one.
- Find the bigger amount. The bigger room is 15 °C.15 °C
- Find the smaller amount. The smaller room is 9 °C.9 °C
- Take the smaller amount away. Subtract to find the difference.15 − 9 = 6
- Write the answer. 6
Check. Add the difference back: 9 + 6 = 15. ✓
Watch out. Start with the bigger number, then take the smaller one away.
Method. Look at what the number means. Compare it with a hot day.
- Look at the number. 30 °C is a high number.30 °C
- Compare with a cold day. A cold day has a much lower number.30 is high
- Decide. So 30 °C is a hot day, not a cold day.No
Check. Higher numbers are hotter. 30 is higher than 10. ✓
Watch out. A higher number means it is hotter.
Method. Read each one, then pick the one that shows 25 °C.
- Read A. A shows 18 °C.A: 18 °C
- Read B. B shows 25 °C.B: 25 °C
- Read C. C shows 26 °C.C: 26 °C
- Find the match. We want 25 °C.B shows 25 °C
- Write the answer. B
Check. A and C do not show 25 °C. ✓
Watch out. Read the top of the red line or the water line for each one.
Method. Add all the temperature together.
- Find each part. We add the temperature together.15 °C + 5 °C
- Add them together. Add one part at a time.15 + 5 = 20
- Write the answer. 20
Check. Add in a different order to check: 5 + 15 = 20. ✓
Watch out. Use the same unit for every part. The answer is in °C.