Do you wear glasses to help you see better?  Do you know someone who does?  Look through your glasses from both sides.  Or look through glasses that belong to someone else.

                                            Do things look smaller - or BIGGER?      

Glass is more dense than air.  If you had a cup of air and a cup of glass, there would be lots more  molecules in the cup of glass.  Molecules are made up of atoms.

We can see things because light bounces off of everything and bounces into our eyes.  A lens changes the way things look because it bends light. 

If you look carefully at the lenses in eyeglasses, you'll find that one part of the lens is thicker than the other.  Sometimes the middle is thicker than the edges.  Sometimes the edges are thicker than the middle. 

A beam of light speeds through air.  But glass is more dense than air.  The density of the glass changes the way light moves.  It bends the light. 

Click here to see how the lens in your eye works!

Want to see how different densities change the way you see? Try this! Find a clear glass and fill it with water.  Put a spoon into the glass.  Look at the the glass from the side.  Does the handle of the spoon look different above and below the water?  Draw a picture of what you see.

Water is more dense than air. There are lots more molecules in the cup of water than in a cup of air. Air and water bend light in different ways because they have different densities.

Want to find out who invented microscopes?  Click Next!

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