When you have a big bubble, twist the hoop to seal it off at the end. Look for patterns and colors in the bubbles. Dip the hoop in the solution and hold it up to the light without forming a bubble. The strong mutual attraction of water molecules for each other is known as surface tension . Normally, surface tension makes it impossible to stretch the water out to make a thin film.
Soap reduces the surface tension and allows a film to form.
Because of surface tension, a soap film always pulls in as tightly as it can, just like a stretched balloon. A soap film makes the smallest possible surface area for the volume it contains. If the bubble is floating in the air and makes no contact with other objects, it will form a sphere, because a sphere is the shape that has the smallest surface area compared to its volume. The patterns of different colors in a soap bubble are caused by interference . For example, if the soap film is thick enough to cause waves of red light to interfere destructively with each other, the red light is eliminated, leaving only blue and green to reach your eyes.