Welcome to Dr. B's Science Lab, a non-commercial resource for up-to-date and accurate science content, activities, and projects. Explore a different topic every month, and get the whole family involved in learning and experimenting! Just be sure to follow the directions exactly and pay attention to any safety information given.

If you would like to receive email updates whenever new content is added to Dr. B's Science Lab, submit your address in the "Follow by Email" link at left. Your email address will not be used for any other purpose.

Monday, August 16, 2010

Angle In = Angle Out

Enough about mirror images. Now let's talk about how light actually reflects off a mirror's surface. There's even a scientific law that says "The angle of reflection equals the angle of incidence." Huh? It's simple - this law just means that the light reflects off the surface at the same angle it hit the surface with. Angle in = angle out!

Look at the figure below:
Can you see that, in both cases, the angle between the mirror (gray line) and the arrow on the left is the same as the angle between the mirror and the arrow on the right?

You can prove this law yourself. Get a small mirror and a laser pointer (never look into the laser pointer and never point it at someone else). Have someone stand facing a wall, holding the mirror so that it points at the wall. Turn the pointer on and position it so that it shines on the mirror. The laser light will bounce off the mirror and hit the wall. Can you find it? Now move the pointer so that the light hits the mirror at a different angle. Does the spot on the wall move? You can also try keeping the laser still and moving the mirror. You should see the laser spot move whenever the angle between it and the mirror changes - it doesn't matter whether it's the pointer or the mirror that moves.

No comments:

Post a Comment