Refraction - Rod In Water
To demonstrate refraction.
Plastic water tank with mounted stick.
The rod, inserted into the water tank and viewed from an angle, shows a discontinuity at the surface of the water. Insert the other end of the rod at an angle into the water; the rod looks bent when viewed at an angle.
R. C. Nicklin and W. C. Connolly, Rugged Refraction Demonstration, AJP 43, 112 (1975). Chris Emery, Refractive Puzzle, TPT 31, 413 (1993).