* Smooth Surface: When the water is still, its surface is very smooth. Light rays from your body hit this smooth surface and bounce back into your eyes at the same angle. This creates the image you see, which is your reflection.
* Reflection: This bouncing back of light is called reflection. A mirror works the same way, reflecting light to create an image.
* Moving Water: When the water is moving, the surface becomes disrupted. The waves and ripples on the water break up the smooth surface. This means that the light rays from your body are scattered in different directions. Instead of all the rays bouncing back to your eyes at the same angle, they are reflected in many different directions, making it impossible to see a clear reflection.