Q 01/05

The Celsius scale is named after an astronomer of which nationality?

A) French

B) German

C) Danish

D) Swedish

Answer · why

D) Swedish

Anders Celsius (1701–1744) proposed the first version in 1742.

Q 02/05

In Anders Celsius's original 1742 scale, what temperature was 0 degrees?

A) The boiling point of water

B) Human body temperature

C) Absolute zero

D) The freezing point of water

Answer · why

A) The boiling point of water

He put freezing at 100; the scale was reversed within two years of his proposal.

Q 03/05

Which French physicist of Lyon inverted Celsius's scale in 1743 to put freezing at 0 and boiling at 100?

A) Joseph Fourier

B) René Réaumur

C) Guillaume Amontons

D) Jean-Pierre Christin

Answer · why

D) Jean-Pierre Christin

He published a mercury 'Thermometer of Lyon' built by the craftsman Pierre Casati that used the modern direction.

Q 04/05

Which botanist reversed the temperature scale in 1744 with a custom greenhouse thermometer?

A) Olof Celsius

B) Emanuel Swedenborg

C) Jöns Jacob Berzelius

D) Carl Linnaeus

Answer · why

D) Carl Linnaeus

His Hortus Upsaliensis of 1745 is the first known Swedish document to report temperatures the modern way up.

Q 05/05

What was the scale commonly called in English before 1948?

A) Centesimal

B) Metric degrees

C) Swedish degrees

D) Centigrade

Answer · why

D) Centigrade

From Latin centum, a hundred, and gradus, steps.