Q 01/05

In which month does Earth reach perihelion, the point in its orbit closest to the Sun?

A) January

B) April

C) July

D) October

Answer · why

A) January

January is perihelion, so Earth is nearest the Sun in the middle of the northern winter; the seasons come from the tilt of the axis, not from distance...

Q 02/05

Which gas causes about half of Earth's greenhouse effect, more than carbon dioxide?

A) Methane

B) Water vapour

C) Nitrous oxide

D) Fluorocarbons

Answer · why

B) Water vapour

Water vapour is the most important greenhouse gas overall, responsible for 41–67% of the effect, but it acts as a feedback to other gases rather than ...

Q 03/05

Without its greenhouse effect, Earth's average surface temperature would be about what, instead of roughly 14 °C?

A) Minus 18 °C

B) Minus 30 °C

C) Minus 6 °C

D) Minus 1 °C

Answer · why

A) Minus 18 °C

Minus 18 °C is colder than a home freezer, and the roughly 32-degree gap is heat trapped by the atmosphere's absorbing gases before it can escape to s...

Q 04/05

Which continent, the coldest, driest and windiest, is a polar desert with only about 150 mm of precipitation a year?

A) Australia

B) South America

C) Antarctica

D) North America

Answer · why

C) Antarctica

Antarctica gets its scant moisture almost entirely as snow, yet over millions of years that trickle has built an ice sheet kilometres thick.

Q 05/05

Which Swedish astronomer's temperature scale first ran backwards, with 0 for boiling water and 100 for freezing?

A) Daniel Fahrenheit

B) Anders Celsius

C) René Réaumur

D) Lord Kelvin

Answer · why

B) Anders Celsius

Anders Celsius died in 1744, and it was the botanist Carl Linnaeus who flipped the scale the following year so that bigger numbers meant hotter.