How_To_Be_Good_At_Math

186 MEASUREMENT •^ TEMPERATURE

Temperature

Temperature is a measure of how hot or cold something is.

We measure it using a thermometer and can record it in units

called degrees Celsius (°C) or degrees Fahrenheit (°F). You might

also hear degrees Celsius called degrees centigrade.

100°C

Boiling water

20°C

Room

Temperature

0°C

Freezing water

0°C (32°F) is the

temperature at

which water freezes.

Look at this

The range

markings on the side of

the thermometer tell us

what the temperature

is, a little like a ruler or

a number line.

If the temperature

gets colder than

0°C or 0°F we put a “−”

sign in front of the

number and count back

from zero. These are

called negative

numbers (see pages

18-19).

100°C (212°F) is the

temperature at which

water boils.

This thermometer says the

temperature is 20°C (68°F).

This is a comfortable

temperature that we often call

room temperature.

Absolute zero

William Lord Kelvin, an

engineer and physicist,

thought that zero should not

represent the freezing point

of water but instead should

represent the coldest possible

temperature in the entire

Universe. He called this

temperature absolute zero,

or 0 K (Kelvin), and it is equal

to −273.15°C (−459.67°F).

REAL WORLD MATHS

The Fahrenheit and

Celsius scales meet

at −40°C (−40°F).

−40

−30

−20

−10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

(^100210)
90
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0
−10
−20
−30
−40
°C °F
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