Light in Our Lives

The caveman's torch made a little in the darkness. Today we light whole cities with electricity.

Important Words:

   Photon - A tiny bundle of light energy.
   Reflection - Bouncing of light rays in the straight lines.
   Refraction - Bending of light rays as they go from one substance to another.

     Have you ever heard someone say, "Turn the light on- I can't see a thing"? For most o the time thats human begins have existed, the only light that they knew was sunlight, moonlight, and starlight, or, somethimes lightning.

      They had to hunt and fish during the day. Later, when they ploughed fields and raised crops, they could work only from dawn to dark. Then they learned to use fire. It lighted their caves and, later houses. Light from fire places was only the light some houses had. Abraham Lincoln read and studied by the light form his fireplace. After learning to use fire, people learned to make oil lamps and then candles. they learned to burn gas to light their homes and streets.

     About 100 years ago, Thomas Edison invented electric light, and  humans had conquered the darkness of night. We would work and study and travel and play whether it was day or night.

Reference: Beginning Science By: Dr. Jerome J. Notkin