Book 20, Question 20
Why Do Faraway Mountains Look Blue?
Faraway mountains look blue because the air between you and them is never perfectly clear! Tiny bits in the air scatter blue light more than red light. Lots of scattered blue light adds up to a blue haze.
More fun facts
- Sunlight is made of many colors mixed together.
- Bits of oxygen and nitrogen in the air scatter blue light the most, which is why the sky looks blue.
- In the Blue Ridge Mountains, trees and plants give off natural gases, mostly one called isoprene.
- These gases change into tiny floating particles that make a haze.
- That natural haze helps give the Blue Ridge its bluish look.
- Hot, hazy summer days can blur the view, while clear winter days can show ridge after ridge.
Sources: National Park Service, National Park Service
Questions kids ask
Does pollution make mountains look blue too?
Pollution adds haze too, but it tends to blur and dull the view. The classic Blue Ridge haze comes mostly from natural gases given off by trees.