Problems for IYPT New Zealand 2012
1. Gaussian cannon
A sequence of identical steel balls includes a strong magnet and lies in a nonmagnetic channel. Another steel ball is rolled towards them and collides with the end ball. The ball at the opposite end of the sequence is ejected at a surprisingly high velocity. Optimize the magnet’s position for the greatest effect.
2. Cutting the air
When a piece of thread (e.g., nylon) is whirled around with a small mass attached to its free end, a distinct noise is emitted. Study the origin of this noise and the relevant parameters.
3. Woodpecker toy
A woodpecker toy (see picture) exhibits an oscillatory motion. Investigate and explain the motion of the toy.
4. Rocking bottle
Fill a bottle with some liquid. Lay it down on a horizontal surface and give it a push. The bottle may first move forward and then oscillate before it comes to rest. Investigate the bottle’s motion.
Paper lanterns float using a candle. Design and make a lantern powered by a single tea-light that takes the shortest time (from lighting the candle) to float up a vertical height of 2.5m. Investigate the influence of the relevant parameters. (Please take care not to create a risk of fire!)
6. Misty glass
Breathe on a cold glass surface so that water vapour condenses on it. Look at a white lamp through the misted glass and you will see coloured rings appear outside a central fuzzy white spot. Explain the phenomenon.
7. Granular splash
If a steel ball is dropped onto a bed of dry sand, a “splash” will be observed that may be followed by the ejection of a vertical column of sand. Reproduce and explain this phenomenon.