Science Fair Ideas

Do you remember a spectacular sunset? Have you ever wondered what makes the sun and sky seem to change color, or why some sunsets are more colorful than others? Here is a way to use the science of light, called optics, to make your own sunset at home.
1. Fill a small, clear plastic or glass container with water.
2. Place the container about 6 inches from a white wall or background.
3. Shine a flashlight through the water toward the background. Is the light you see on the background the color of the sun in the middle of the day?
4. Now, add a few drops of milk to the water. What color is the light now? Add a few more drops of milk.
5. Experiment with different amounts of milk. Which is your favorite sunset color?

What’s going on: Light is made of waves. White light, from the sun or a flashlight, is made up of different colors, each color having a different wave length. The particles of milk solids scatter the blue and green light, the shortest wave lengths, and only the yellow, orange and reds, the longer wavelengths, pass through. When the sun is low in the sky, the light passes through more atmosphere (and particles) before it reaches us, so more of the blue and green light is scattered, and we see the familiar reddish sunset.

Post what you did with the experiment. Which variables did you change – the amount of milk, the type of light, the shape of container? Can you use what you have learned to explain why the sky looks blue?
Fernwood’s science fair is on the horizon! Projects will be presented 16 April 2010. If you’re interested in helping with the event contact Amy Oliver at AmyROliver@gmail.com.