Topic: loaded test-tube in a liquid

Loaded test-tube can be used to demonstrate simple harmonic motion in the laboratory. The test- tube is loaded with iron fillings or sand (make sure that the sand is enough to make the tube stand vertically in the liquid). Press the tube into the liquid(water) and release it . the tube move up and down in an oscillatory motion. The motion of the loaded test tube is a simple harmonic motion .   ...