A soap bubble is a thin film of soap solution that forms a spherical shape when air is trapped inside. The film is made up of a layer of water sandwiched between two layers of soap molecules. This structure allows the bubble to reflect light, creating colorful patterns on its surface. Soap bubbles are often used in science experiments and play because they are visually appealing and demonstrate properties of light and surface tension. They can float in the air and pop easily when they come into contact with sharp objects or surfaces, such as fingers or grass.