-Fill rocket about 1/3 full of water.
-Insert pump into rocket, slide catch on and pump 20-25 times.
-To release rocket aim and slide catch off rocket.
-You will probably get wet.
-Pump the same number of times without water to show the difference in range.
-Place a tennis ball on top of a basketball and drop from a height of about 4 feet.
-Warn the audience that the tennis ball may fly astray.
-Observe the effects of displacing different numbers of balls. Try one ball first, then two and so on up to five balls at once.
-If this does not work well there may be a misalignment problem. First check that the wires are hanging straight., then try adjusting the length.
-The track will already be leveled. Turn on the air supply under the lecture bench.
-TRICK: To give two carts the same velocity place a meter stick on top of both carts. When they are moving lift the meter stick before the first cart reaches the end of the track. It will rebound with equal and opposite velocity.