Internal Reflection

To demonstrate this phenomenon, a video is released in which a laser is positioned on one side of a clear tank of water. | A cool thing called 'total internal reflection happens when you point a laser beam at a jet of flowing water. | Even as the water flow is gradually decreased, the laser beam remains contained inside the jet, until it eventually disappears when the water is turned off completely. | When the light travels through the water, it is slowed by the heavier particles in the water, effectively 'trapping' the laser beam in the water.