Refraction

Light energy cannot only be reflected but can also be bent.

Look at the image below. Why does the straw appear broken? If you take the straw out of the water, you will find out that it is still one whole piece. When placed back in the water, what causes it to look broken?

Light travels at a very fast rate. However, this speed slows down when light travels through an object, such as the glass and water in the image. The decrease in the speed of its travel results in light being bent in a phenomenon called refraction.