Applied Science - Physics (1A) Pre Lab
 OBJECTIVES: Comparing reflect and refract. Discovering how light moves. VOCABULARY: lens reflect refract diffract MATERIALS: worksheet crayons glass of water spoon Light Magic   by Joyce Blueford Students compare reflect and refract using worksheet
 BACKGROUND: 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. 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.  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. PROCEDURE: Bring in some lentils for students to see where the word "lens" comes from. Many students (unless from Mediterranean area) are not familiar with lentils as a food source.    Put a spoon in a glass of water is about 1/3 full. Let the students view the spoon through the side. The light makes it refract. Students should be familiar with looking at a mirror or their image in a lake, which is a "reflection."    The worksheet goes over the words "reflect" and "refract." Reflect is light actually deflecting backward or bouncing. Refract is light passing through a substance and changing its course of direction. The worksheet pictures identify the terms reflect or refract. Instruct students to color each picture and trace over the word. A spoon in water when viewed from the side looks bent. This is refraction. A mirror reflects an image. Water will also reflect an image. Light through a lens is refracted. Read Light Magic to student.  The story reinforces the vocabulary words.  The story also gives students more information about light including the reason for rainbows and other visual effects caused by mirrors.