Thin Film Interference: Bubbles and Rainbows "Note: This activity has been modified for distance learning. Originally, you would have received a bottle of bubbles with a loop. If you have a bottle of bubbles in your home, use it. Bubbles: Make some bubbles. You can use hand soap or dish soap. IGet a good lather going. Make a circle with your thumb and pointer finger. Try to get the soap film to form a layer inside the circle. Hold your hand vertically so the film begins to fall. If you can't get the soap film to adhere, look at the bubbles on your hands. Have a light source, like a window, behind the bubbles. Observe the film and the bubbles. Do you see the fringes? What do they look like? Why do you think there are many colors? What makes the dark bands? Can you see evidence of constructive interference? Destructive interference? What are the fringes doing? What determines what the fringes look like? Blow a few bubbles off your hands. Try to catch a bubble. You can use a straw, clothes hanger, plastic utensil, you may even be able to catch one with your hand. Observe the colors as the bubble "ages" and pay close attention at the moment just before the bubble pops. What happens when the bubble gets "old"? Why do you think this happens? Oil and Water Don't Mix During or after a rainfall, you may have noticed brilliant colors on a wet driveway or parking lot where oil has dripped from a car engine. To reproduce this situation, cover the bottom of a pan or bowl with a thin layer of water. Place a drop of oil on the water and look at the oil slick with various angles of incident light. Describe what you see occurring in the oil on the water. Read: Find information online about thin film interference. Describe thin film interference. Explain in proper physics terms the production of the color patterns seen the bubbles and in the oil. If you have difficulty accessing the textbook, go online and read about thin film interference