How are rainbows
Rainbows are caused by another aspect of refraction called dispersion. Light waves of different frequencies (colors) bend different amounts. In most cases, this is not
noticeable, but prisms make use of this to spread out the spectrum so we can see all of the colors. Violet light bends the most, with each color bending a little less up to red, which bends the least.
If light is bent when it passes through glass, is everything we see through a glass window actually in a
Light is bent when passing through a transparent material. What happens when you look out a window?
Does the bending of
light mean that nothing is where it appears to be?
Refraction does when you look out a window, but the effects of the bent light
is canceled out. A clear glass has two surfaces that the light passes through - the inside surface of the glass and the outside surface of the glass. When the light passes through the inside surface of the glass the path is bent in one direction and when the light passes back out through the outside surface of the glass it is bent in the other
direction. They cancel each other out and there is no
noticeable effect from refraction.
Websites with information on
Light refraction and spear fishing
Calculate index of refraction
Experiments with Refracting
1. Make a Rainbow (glass of water, white paper, sunlight)
Fill a glass full with water. Carefully put the glass on the edge of the table so that it is half on and half off, without tipping over! Make sure the sun is shining through the water. Position the white paper on the floor so that the rainbow shows on the paper.
2. Where is it? (clear bowl, pebles or beads, water)
Put the pebbles or beads into the clear bowl and fill it with water. Look through the side of the bowl. What do you notice. Continue looking through the side of the bowl, and try and pick them up. Which ones are easiest to touch? Which ones are harder? See if you can figure out why?