Double Rainbow Explained

You may know the famous double rainbow video from Tosh.0

The video below gives a short summary of what science can tell us about what is going on with a double rainbow

http://videos.howstuffworks.com/discovery/41294-earth-giant-double-rainbow-explained-video.htm

Check out this site for great info on rainbows and other atmospheric phenomenon

Free-Falling

The video illustrates the fundamentals of gravity.

Physical objects attract each other with a force proportional to the mass.

Free-fall is a result of the gravitational force between the earth (or in this case the moon) and the object falling (in this case the hammer and the feather).

Because the force between these two objects in proportional to mass, the acceleration is the same for all falling bodies.

Why on earth does a feather fall slower than a hammer? Air resistance

The moon has essentially no atmosphere (a vacuum) so there is no air resistance and we see how falling bodies fall at the same rate despite their mass

The moons gravity is ~16.7% that of earths

(~1.63m/s^2 on moon~ 9.81m/s^2 on earth)

This is due to the fact that the moon is much lass massive than the earth

The decreased gravity allows us to see the free fall in slow motion compared with what would see on earth.

The first scientist to figure this out was Galeileo Galilei, who also greatly improved the design of the telescope, and helped prove Copernicus's theory of Heliocentrism

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