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The Earth's Atmosphere - Why Is the Sky Blue?

This Teaching Astronomy and Space video, from the Institute of Physics (IOP), Teachers TV and the Science and Technology Facilities Council (STFC), helps to explain the answer to a simple question: why is the sky blue?

Using a light source, a beaker of water and a few drops of milk, students can see how the milky water scatters blue light. This effect happens in the earth's atmosphere and the scattered blue light is seen as a blue sky. This is called Rayleigh scattering.

It also shows that the transmitted light is red in colour and explains why sunsets sometimes appear red.

Please refer to the information and acknowledgements for this resource.

STFC is a part of the Research Councils UK (RCUK) partnership of research councils.

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