Pull it out again and slowly separate the two straws. A film should form around the loop. If it doesn't break, pull the loop through the air to form a giant bubble. Other things to try are funnels, the tops from plastic drink bottles, and the loop formed by a thumb and index finger. Soap bubble lore Colors Soap bubbles are a layer of soap film on the outside, a layer of water molecules in the middle, and a layer of soap film on the inside.
Light reflects from the first and second layer of soap film.
The light waves interfere with each other, adding to or subtracting from each other's frequencies, which changes the color reflected. The interference colors are determined by how far the light waves that are reflected from the inside layer must travel to meet the waves reflected from the outside layer. So the different colors of the bubble actually correspond to its thickness at different points. Shape Soap bubbles are elastic and will contract to form a sphere, which provides the most volume for the least surface area. To build a bubble tank you need a large clear box that is open at the top.