101 Phy Tricks
pg 89: Some metals that are left unprotected may begin to rust. Use samples of steel wool or clean iron nails or even straight pins to see why this happens. Leave one piece of steel wool or some nails or pins in a plastic dish with a little water. Keep the sample damp. In another dish completely cover the wool or nails in water from a kettle that has boiled and then gone cold. Leave a third sample in a dry dish in a warm, dry spot. What do you predict will happen to your metal samples?



pg 86: Put a candle in a dish of water. Ask an adult to light it. Put a glass jar over it, resting on some coins to keep a gap between the jar and dish. As the candle burns, it uses up part of the air in the jar. The space left by the used up air is filled by water sucked in from the dish, but it only fills about a fifth of the space in the jar.


pg 87: To put out a fire you must stop oxygen from reaching it. Water will drench the fire, so air can't reach it, fire-proof blankets can be thrown over small fires, and foam or carbon dioxide extinguishers will smother a fire in the same way. You can make your own carbon dioxide extinguisher with bicarbonate of soda and vinegar. The baking soda reacts with the acid in vinegar to make carbon dioxide gas. Ask an adult to help you set up a small candle in a sand tray and mix the ingredients in a large beaker. As the mixture froths, hold the beaker above the flame. Don't pour the liquid on the flame, just let the gas flow over the flame.


Simple Harmonic Motion
Arrange two pendulums same length hanging on a string. Start one swinging and watch the other one.
Time period of a swing with and without a person on it.

Turning the World Inside Out
G3: A small ball in an inverted plastic cup can be made to revolve faster and faster by shaking the cup at the right frequency, thereby illustration both resonance and the principle of the synchrotron. In addition , the ball can be made to climb the steep walls when the cup is righted and shaken at a high enough frequency.
G4: A "tin" can, into which a number of vertical strips of varying lengths have been cut, can be used to show resonance of one particular strip when a strip of the same length on the other side of the can is plucked.
G5: You can find the resonant frequency of a hand-held spring from which a hanging weight is suspended, by gently shaking the top of the spring at different frequencies and seeing how the amplitude varies.