What comes first, lightning or thunder?

by: Google Images

               Lightning comes first before thunder does because light travels faster than sound.


http://www.vernonkids.com/cedarmountain/4thgradelinks/tests/Lightning/ThunderLightning.htm

Why the sky is blue?

      

by: Google Images

        
       A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.  When we look towards the sun at sunset, we see red and orange colors because the blue light has been scattered out and away from the line of sight.


http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html

Where does a rainbow come from?

by: Google Images

  

       A rainbow  is an arc-shaped spectrum of color seen in the sky opposite the Sun, especially after rain. It is caused by the refraction and reflection of sunlight by droplets of water suspended in the air. The colors of a rainbow are usually identified as red, orange, yellow, green, blue, indigo, and violet.

http://eo.ucar.edu/rainbows/