Refraction of light

The film shows that light is refracted when it encounters another transparent material at an angle other than 90°, the normal. The second material must have a different refractive index; here, water and air are compared. The speed of light in air is approximately 300,000 km/s, and in water, it's 225,000 km/s. The light ray is refracted when it hits the surface of the water. In optically denser materials, all light can be reflected, a phenomenon known as total internal reflection. The film demonstrates total internal reflection in plastic and shows that it doesn't occur in a "tube of air" surrounded by plastic. If you're interested in light and its refraction, read more in "Physics 9" by Kaj Schmidt in Apple Books