Why is the sea blue?

  • 1 Replies

0 Members and 1 Guest are viewing this topic.


Offline thedoc

  • Forum Admin
  • Administrator
  • Sr. Member
  • *****
  • 513
    • View Profile
Why is the sea blue?
« on: 09/04/2013 14:30:02 »
Happy Camper  asked the Naked Scientists:
Hello, I have listened to Naked Scientists for a long time and I have never heard this question asked,"Why is the ocean blue?"

If I go to the bluest lake and take some up in a glass and look through it, it's not blue, it's clear. When I go to large aquariums, the water is clear there too. What's up with that?

Any insight would be appreciated, Charlie

What do you think?
« Last Edit: 09/04/2013 14:30:02 by _system »


Offline chris

  • Neilep Level Member
  • ******
  • 5424
  • The Naked Scientist
    • View Profile
    • The Naked Scientists
Re: Why is the sea blue?
« Reply #1 on: 09/04/2013 20:13:44 »
Hello Charlie.

The sea "looks" blue because water molecules form sticky inter-molecular associations called hydrogen bonds between different molecules. This subtly alters the O-H bonds in the molecules, causing them to absorb more red light (in the atmosphere, where water molecules exist as single vapour molecules and occasionally as dimers or trimers, they absorb more infrared radiation rather than red light, which is why water is a greenhouse gas).

The result of this absorption of red light in the ocean is that white light (from the sun) is returned to you minus some of the red, making the water look more blue. The same thing happens in ice.


I never forget a face, but in your case I'll make an exception - Groucho Marx