成人快手

Science presenter Jon Chase explains total internal reflection.

He demonstrates how total internal reflection can make a coin disappear inside a glass of water and bend a laser beam. The second demonstration is used as a model for fibre optics.

Teacher Notes

Your class could repeat the demonstration with the glass and the coin. Ask them to draw light ray diagrams to show what happens when they move their head higher or lower.

There are a variety of ray diagrams possible, depending on the position of the viewer and the amount of water in the beaker.

Students could also investigate total internal reflection using ray boxes and blocks of Perspex and glass, measuring the critical angle in each case.

Total internal reflection could also be demonstrated by the teacher using a laser beam shining through these blocks, or even through a rectangular block of gelatine.

Curriculum Notes

This short film will be relevant for teaching physics and science in general at KS3 and KS4 in England, Wales and Northern Ireland and National 4/5 in Scotland, and Cambridge IGCSE Physics

More from Physics Bites:

Falling bodies. video

Jon Chase describes Aristotle鈥檚 and Galileo鈥檚 theories about falling bodies.

Falling bodies

Newton's Third Law. video

Science presenter Jon Chase explains Newton鈥檚 third law.

Newton's Third Law

Radioactive decay. video

Jon Chase explains radioactive decay.

Radioactive decay

Refraction of light. video

Jon Chase explains the refraction of light.

Refraction of light