An activity from Dave Mastie (Ann Arbor, MI)
Type of Lesson: Hands-on Activity/Discussion
Time Needed: 15 minutes
Physical Science, Grades K-4: Objects have many observable properties, including size, weight, shape, color, temperature, and the ability to react with other substances. Those properties can be measured using tools, such as rulers, balances, and thermometers.
Physical Science, Grades K-4: Light travels in a straight line until it strikes an object. Light can be reflected by a mirror, refracted by a lens, or absorbed by the object.
Physical Science, Grades 5-8: Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection). To see an object, light from the object-emitted by or scattered from it-must be enter the eye.
1. Fill container 3/4 full of tap water.
2. Press masking tape onto sheet of construction paper so it acts as a handle to pull construction paper out of water.
3. Place construction paper under water, but leave masking tape handle above water.
4. Add one drop of clear fingernail polish.
5. Remove construction paper by lifting on masking tape handle. Allow nail polish film to run over surface of paper. Caution: Take care in lifting the film off onto the paper because the film tends to slide off easily!
6. Allow your paper to dry on the paper towel.
You can see step-by-step images of the activity here.
Use this activity as a "teaser" to a discussion on light and light interference. When the drop of fingernail polish is dropped onto the surface of water, it spreads out forming a film on top of the water. When the paper is pulled out of the water, it captures the rainbow of colors (it "freezes" the film of colors!). This color display is like the oil films we see at gas stations, the mother-of-pearl inside seashells and soap bubble surfaces. Note: dark colors of construction paper will work best for this activity!
For elementary students, teachers have found it fun to do this exercise when making thank you cards. Other colors of construction paper can be used (full sheets if wanted by using a 9x13 pan) as base for thank you cards or art lessons! If you use a whole sheet, students may be able to draw on top of the frozen film right after it is taken out of the water. This is neat for making Easter egg decorations or faces or....
For advanced students, you may want to discuss that interference is defined as the mutual effect of two wave trains that meet, resulting in the loss of intensity in certain regions and a reinforcement of intensity in other regions. Isaac Newton was one of the first to experiment with thin films and their effect on color. When viewed by reflected white light, thin transparent soap films, oil slicks and layers of shell show varying patterns of colors. These variations in color are due to the interference of light waves.