Measure
Temperature
Temperature tells us how hot or cold something is. We measure temperature in degrees Celsius using a thermometer.
Degrees Celsius
Temperature is measured in degrees Celsius. We write it with the short sign °C. We need to know temperature for cooking, for the weather, and to choose the right clothes to wear.
Reading a thermometer
A thermometer has a red line that rises and falls. The longer the red line, the hotter it is. Read the number the top of the red line reaches. If the line reaches the 15 mark, the temperature is 15 °C.
Scales that count in steps
Thermometer scales count up in steps. Some go up in 5s (5, 10, 15, 20) and some go up in 2s (2, 4, 6, 8). To read to the nearest marked division, choose the mark the line is closest to.
Hotter and colder
A higher number means it is hotter; a lower number means it is colder. So 25 °C is hotter than 18 °C, and 5 °C is colder than 30 °C. To find the difference, subtract the smaller from the larger.
Worked examples
Reading the scale
- Find the top of the red line.
- It reaches the 15 mark on the scale.
- The scale is in degrees Celsius.
Answer: The temperature is 15 °C.
Which is hotter
- Thermometer A reads 15 °C.
- Thermometer B reads 20 °C.
- 20 is a higher number than 15.
Answer: Thermometer B shows the higher temperature.
A temperature that goes up
- This morning it was 18 °C.
- It went up by 7 °C by 3 o'clock.
- Add: 18 + 7 = 25.
Answer: At 3 o'clock it was 25 °C.
Where you see this in real life
- Checking the weather to decide what to wear.
- Setting the oven to the right temperature for baking.
- Reading a thermometer to see if water is warm or cold.
Key words
- Temperature
- How hot or cold something is.
- Degrees Celsius (°C)
- The unit we use to measure temperature.
- Thermometer
- An instrument that measures temperature.
- Division
- A marked line on a scale.