Physics helps us explain the world around us. There are many things occurring in the world that we can't explain. This unit has students investigating the properties of light. They will not understand the physics of light, but will begin the process of becoming familiar with some of the bizarre things light can and cannot do.
The world is full of images for children. A reflection in a mirror or window can scare them; a penny in a pool may look closer than it really is. Light has always played with our sense of sight. Children can learn how these images are different from the real thing. Children need to discover that they can change the way light moves. As children play with optic toys, they begin to see that light can play tricks with their eyes.
Young children need to experience different examples of reflect and refract to recognize them easily. Reflect is easier to understand than refract. Reflection is just a "bouncing" back of an image, while refraction is a change of direction of an image. A prism, for example refracts or bends light to create a rainbow. However, with just a little guidance, students can look at light and identify whether it refracts or reflects
Light can be controlled by lenses, prisms, and mirrors. Light moves. Lenses are important in our everyday life. Many people wake up putting on eyeglasses or contacts. People who take pictures use lenses in the cameras. Lenses are in magnifiers, lighthouses, microscopes, telescopes, binoculars and projectors. Nature has found a natural way to create a lens system in most organisms (eyes) so they can see. The word lens comes from the Latin word "lentil," (a bean used in soup that is biconvex.)
A prism causes light to change direction or refract as it moves through the prism. Light when it travels through different substances can also refract. It appears to our eyes as if the object is bending, but it is only "light" playing tricks with our eyes. A mirror allows light to "bounce" or reflect from the surface of the mirror. We see ourselves in the mirror because light reflects or bounces from the mirror and the image is captured by lenses in our eyes. Light can also diffract when it goes through a small slit. The light particles spread from the center into distinct packages. Depending on your class we usually do not expect the students to learn this term, but saying the term is allowed.
Many people do not realize that light is actually a real phenomenon. It moves, it changes directions, and it is part of a branch of physics called the electromagnetic wave spectrum.
After they see infinity, you can also have them hold the mirror horizontally at eye level so that the students either see the ceiling or the floor. They can tilt the mirror back and forth so it looks like people are walking on the ceiling. They usually get very excited doing this.