Bubbles are formed due to the surface tension of water. This tension is the mutual traction force that exists inside the object and is perpendicular to the contact surface of two adjacent parts when the object is subject to tension. The attraction between water molecules on the water surface is stronger than that between water molecules and air. These water molecules are like being stuck together. However, if the water molecules are excessively bonded together, bubbles are not easy to form. Soap "breaks" the surface tension of water. It reduces the surface tension to only 1/3 of that under normal conditions. After the bubble is formed, a large surface tension is required to make the bubble bigger.

There are manual bubble guns and automatic bubble guns. The manual bubble gun is driven by pulling the trigger by hand, while the fully automatic bubble gun is driven by the motor to drive the tooth wheel. There are two movable wheels on the top of the last tooth wheel. The movable wheel is divided into two sides to squeeze the hose next to it, mainly by squeezing the hose section by section, and then the water can be pumped up to blow out a long string of bubbles.