Q 01/05

Which food, properly stored, essentially never spoils, with samples from ancient tombs still edible?

A) Olive oil

B) Hard cheese

C) Dried rice

D) Honey

Answer · why

D) Honey

Honey keeps almost indefinitely: its low water content, high sugar concentration and acidity stop microbes growing, which is why archaeologists have f...

Q 02/05

On which planet does a single day (one rotation) last longer than its year?

A) Mercury

B) Venus

C) Mars

D) Jupiter

Answer · why

B) Venus

Venus takes about 243 Earth days to spin once on its axis but only about 225 to circle the Sun, so its day outlasts its year; it also spins retrograde...

Q 03/05

Which everyday fruit is radioactive enough to serve as an informal unit of radiation dose?

A) Apple

B) Orange

C) Banana

D) Grape

Answer · why

C) Banana

The 'banana equivalent dose' comes from naturally occurring potassium-40, and eating one is worth roughly 0.1 microsieverts.

Q 04/05

The air around a lightning bolt heats to roughly what temperature?

A) 300 °C

B) 3,000 °C

C) 10,000 °C

D) 30,000 °C

Answer · why

D) 30,000 °C

A lightning channel heats the surrounding air to roughly 30,000 °C, about five times the temperature of the Sun's surface; the air's explosive expansi...

Q 05/05

On a hot day, the top of the Eiffel Tower can lean away from the sun by up to how much?

A) 1 cm

B) 5 cm

C) 10 cm

D) 18 cm

Answer · why

D) 18 cm

Heat makes the sunlit side of the Eiffel Tower's iron expand more than the shaded side, so the whole tower bends away from the sun, its top shifting b...