Uploaded March 2024 | Updated September 2026, 2 weeks ago
I shot a laser into the side of a container filled with oil and water. The laser initially entered the oil layer. When the light hit the oil-air boundary, its angle of incidence was greater than the critical angle for vegetable oil and air (about 43 degrees), so all of the light is reflected back into the oil. No light is refracted out into the air. This is called total internal reflection.
Total internal reflection happens again when the light hits the oil-water boundary. The angle of incidence is greater than the critical angle for vegetable oil and water, which is around 65 degrees.
Total Internal Reflection (Demo #1): youtu.be/eH9xyb7sbJQhttps://youtu.be/eH9xyb7sbJQ
When light travels from a medium of higher index of refraction (oil) to a medium of lower index of refraction (air) the light bends farther away from the line perpendicular to the boundary between the two surfaces. If the angle of the light is greater than the "critical angle" for oil and air, then all the light will be totally internally reflected. None of the light will be refracted into the air.
I shot a laser into the side of a container filled with oil and water. The laser initially entered the oil layer. When the light hit the oil-air boundary, its angle of incidence was greater than the critical angle for vegetable oil and air (about 43 degrees), so all of the light is reflected back into the oil. No light is refracted out into the air. This is called total internal reflection.
Total internal reflection happens again when the light hits the oil-water boundary. The angle of incidence is greater than the critical angle for vegetable oil and water, which is around 65 degrees.
Total Internal Reflection (Demo #1): youtu.be/eH9xyb7sbJQhttps://youtu.be/eH9xyb7sbJQ
When light travels from a medium of higher index of refraction (oil) to a medium of lower index of refraction (air) the light bends farther away from the line perpendicular to the boundary between the two surfaces. If the angle of the light is greater than the "critical angle" for oil and air, then all the light will be totally internally reflected. None of the light will be refracted into the air.
