ShareForce, Energy, & Motion - Finding Color in Light!
Light is one part of the electromagnetic spectrum. It usually travels through space as electromagnetic waves. Light can be seen, while many other waves of the electromagnetic spectrum cannot be seen. The electromagnetic spectrum includes radio waves, infrared rays, visible light, ultraviolet rays, x-rays and gamma rays.
Often, people think of light as being the typical white light that is seen. White light is made up of many different colors. Each color in light has a different wavelength. Our eyes respond to the different wavelengths (frequencies) by seeing the different colors.
Materials:
- Small empty baby food jar
- Empty can
- White paper
- Water
- Directional light source (such as a bright flashlight)
Procedure:
- Set the can at one end of the white paper.
- Set the baby food jar on top of the can.
- Direct the light source across the top of the jar at a sharp angle so the shadow from the can falls across the paper.
- Fill the jar with water until it brims above the lip.
- The rounded edge of the water should refract a spectrum of color onto the shadow part of the white paper.
Safety concerns: 
Be sure to follow all glassware, eye, electrical,
and chemical safety rules
that are specified by your teacher in all general laboratory experiences.
As with all science lab activities, the most important safety rule is to follow all teacher directions.
Analysis:
- List the colors as you see them. (If you did this correctly, you should see six different colors.)
- Place the colors in order of decreasing wavelength (hint: red light has the longest wavelength.)
- What differences in observation did you notice as you added water to the jar?
Extension:
- Use the previous experiment as your control and now introduce new variables.
- You might try the following:
- Different light source (perhaps using a mirror to direct sunlight or an over head projector)
- Different colors of Saran Wrap® over a flashlight
