When a balloon bursts, it creates a loud noise due to the rapid release of pressurized air. The noise is the result of a sudden increase in pressure and the subsequent release of that pressure.
When a balloon is inflated, the air inside it exerts pressure on the balloon's elastic walls, causing it to stretch. The stretched rubber of the balloon stores potential energy. As the balloon reaches its maximum capacity or encounters a sharp object or excessive force, the tension on the rubber becomes too great, and it can no longer contain the air pressure. The rubber suddenly ruptures or tears, allowing the pressurized air to escape rapidly.
When the air rushes out of the balloon, it creates vibrations in the surrounding air molecules. These vibrations travel as sound waves, which our ears perceive as a loud popping or bursting sound.
The sudden release of energy and the subsequent noise can indeed be surprising or startle people, especially if they are not expecting it. However, it's a natural outcome of the rapid expulsion of air when the balloon bursts.
It's worth noting that the noise level can vary depending on factors such as the size of the balloon, the amount of air pressure inside, and the material from which the balloon is made.