Question 1

Why does Britain use both Celsius and Fahrenheit?

Accepted Answer

The UK officially adopted Celsius in 1965 and it is the standard for forecasts, ovens and science. Fahrenheit survives informally in newspaper headlines about hot weather, largely because a summer temperature sounds more dramatic in the nineties than in the low thirties.

Question 2

At what temperature do Celsius and Fahrenheit read the same?

Accepted Answer

Minus forty. The two scales cross at −40°, which is the only point where a reading is identical in both.

Question 3

What is absolute zero?

Accepted Answer

0 K, or −273.15°C, or −459.67°F. It is the point at which molecular motion stops entirely, and it cannot be reached, only approached.

Question 4

What was the Réaumur scale used for?

Accepted Answer

Réaumur set freezing at 0 and boiling at 80, giving convenient whole numbers for brewing, dairy and spirits. It was standard across much of continental Europe into the 1800s and appears throughout period British scientific and industrial writing.

Question 5

How do you convert Celsius to Fahrenheit in your head?

Accepted Answer

Double it and add thirty. That gives 30°C as 90°F against a true 86°F, which is close enough for weather. For accuracy, multiply by 1.8 and add 32.

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