WHAT MAKES THE SKY AND SEA BLUE

SKY

Sunlight enters our atmosphere and collides with oxygen and nitrogen atoms.The colour with the shorter wavelength is scattered more by this collision. Because violet and blue are the shortest wavelengths the sky appears to be violet/blue.

SEA

Sunlight strikes the water and is reflected back as blue colour. Also the water droplets in the sea reflect the colour of the sky which is blue on a clear day.