Applied Science - Physics (5B) Post Lab
 OBJECTIVES: Comparing reflection and refraction. Analyzing optical images. VOCABULARY: image reflection refraction MATERIALS: worksheet Light Slideshow Students use a worksheet to compare, reflect and refract.

BACKGROUND:

When light hits a surface, part of the light is reflected. On a clean and polished metallic surface almost 100 percent of incident light is reflected, while on a surface of clear glass only a small amount is reflected. When light bends as it passes from one medium to another, this is called refraction.

PROCEDURE:

1. Draw the following diagrams on the board to illustrate both principles.

In the kaleidoscope that students made, reflection produces the images. Not all flat surfaces reflect as well as others. Aluminum foil in a kaleidoscope does not work as well as Mylar because aluminum is not as reflective as Mylar. Mylar is not as good as a mirror which has a backing of a silver compound.

1. Introduce how different lenses can move light by either refraction or reflection. Different lenses can control the type of picture we take or even how we see. Go over the different shapes of the lenses as shown in the worksheet. Introduce the terms biconvex, biconcave, plane convex, planar concave, meniscus convex, and meniscus concave which just refer to their shape.

2. Instruct students to try and figure out how light will react in each of the different situations. Remind students to look for a mylar surface. This will determine whether the light is reflected or refracted. The color and the clarity of the lens also determines if all light passes through or if some is refracted.