Water droplets bouncing off the walls can be attributed to a phenomenon called the Leidenfrost effect. When a liquid comes into contact with a hot surface, it forms a thin layer of vapor between the liquid and the surface. This layer of vapor acts as a cushion, preventing the liquid from wetting the surface. As a result, the liquid droplet bounces off the surface. The Leidenfrost effect is commonly observed when cooking, where water droplets bounce off a hot skillet.