Watch the colors change over time. You can blow gently on the dome with the straw and swirl the colors. All kids like bubbles. This activity can be used to introduce the concept of light waves and interference patterns to older students. You can also have them compare different brands of soap and decide which one makes the best bubbles.
Light is made of waves like the waves in the ocean.
Light waves, like water waves can interfere with each other. The light dome inside the bubble is being reflected from the inside of the bubble. A bubble film is like a sandwich, a layer of soap molecules, a filling of water molecules and another layer of soap. When the light reflected from one soap layer meets the light reflected from the other, they interfere with each other. The very thinnest film looks black because all the reflecting light waves cancel each other.