Q 01/05

What atmospheric phenomenon primarily causes the Earth's sky to appear blue during the day?

A) Rayleigh scattering

B) Mie scattering

C) Refraction

D) Diffraction

Answer · why

A) Rayleigh scattering

Rayleigh scattering is the scattering of electromagnetic radiation by particles of a much smaller wavelength, such as nitrogen and oxygen molecules in...

Q 02/05

Which blue pigment, once as valuable as gold, was made from lapis lazuli?

A) Cobalt blue

B) Prussian blue

C) Indigo

D) Ultramarine

Answer · why

D) Ultramarine

Ultramarine, meaning 'beyond the sea,' was historically produced by grinding lapis lazuli, a mineral primarily mined in Afghanistan. Its high cost and...

Q 03/05

Which marine arthropod has blue blood due to its copper-based pigment, hemocyanin?

A) Lobster

B) Octopus

C) Horseshoe crab

D) Squid

Answer · why

C) Horseshoe crab

Horseshoe crabs have hemocyanin, a copper-based protein, in their blood that carries oxygen. When oxygenated, it gives their blood a distinctive blue ...

Q 04/05

Which pigment class gives many flowers and fruits their blue, purple, and red colours?

A) Carotenoids

B) Anthocyanins

C) Flavonoids

D) Chlorophylls

Answer · why

B) Anthocyanins

Anthocyanins are water-soluble pigments in plant vacuoles that appear red, purple or blue depending on pH and other compounds in the cell. They give m...

Q 05/05

In Western culture, the idiom 'feeling blue' is commonly associated with which emotion?

A) Anger

B) Sadness

C) Excitement

D) Envy

Answer · why

B) Sadness

The phrase 'feeling blue' is widely used to describe a state of sadness or melancholy. Its origin is debated, but some theories link it to old maritim...