Episode 4

S3 E4: ULTRASONIC CLEANER - Mr. Wizard and Christian discuss supersonics and ultrasonics. Several demonstrations ensue. MANHOLE COVERS - You've seen manhole covers on the street many times. They're usually round. Why? Mr. Wizard explains the logical reason. JAR OVER CANDLE - Leila puts a jar over a lighted candle fixed in a bowl of water. The flame goes out and water rises up into the jar. The usual explanation is that the flame used up some of the oxygen in the air inside the jar and the atmospheric pressure pushed the water up to take the place of the oxygen. The explanation is wrong. Mr.Wizard explains. BICYCLE GEARS - Mr.Wizard shows how bicycle gears work. SUPPORT & BALANCE - Mr.Wizard & Stacey examine support and balance using knives and a cup. HARVESTING OYSTERS - The tide has gone out in the South Carolina inlet, so the men can inspect the oyster beds and mark them with saplings. Once the oysters were harvested by hand. But these men will harvest the oysters in a new way with a machine. BALLOON INTO A BOTTLE - Darren attempts to blow up a balloon inserted into a glass jar. He finds he can't do it because as the balloon expands, it blocks the air from escaping from the jar. Mr. Wizard puts a straw into the jar alongside of the balloon to solve the problem.