Soap and Engines

In this episode of Beakman’s World, Beakman gets a grip on two forces you cannot see: the surface tension that soap breaks apart to clean a dirty letter, and the tiny explosion that a car engine tames to turn a wheel. Don and Herb open the show from the South Pole, Lester dresses up as a soap opera superhero, and Josie keeps everyone on track long enough to actually read the mail.

In this episode you will discover:

• Why water behaves as if it has a stretchy skin on top
• How soap breaks that skin, called surface tension, so water can reach dirt
• How soap binds to oil and grease so wetter water can wash it away
• The four strokes inside a car engine: intake, compression, power and exhaust
• How a spinning crankshaft turns an engine’s up and down motion into rolling wheels
• Why car tyres are black

Breaking one force, taming another

Beakman spends this episode showing what happens once you understand a force you cannot see. Soap works by breaking the invisible skin on water called surface tension, letting water slip into every crack of a dirty shirt or a grubby letter. A car engine works by controlling a much bigger force, a tiny explosion of gasoline and air, and turning that violent push into the smooth turn of a wheel. Different forces, same trick: understand what is really happening, and you can put it to work.

Beakman’s demonstrations

Beakman shows a live water strider bug walking on a pan of water, held up by nothing but surface tension, then floats a basket on that same skin before spraying it with soap so the skin breaks and the basket sinks. Lester appears as a caped cleaning superhero to help wash a filthy letter, and a dirt on cloth demonstration shows plain water cannot clean, while soap and a little elbow grease can. For the engine, Beakman uses a see through model with red and blue dots for gasoline and air to walk through the intake, compression, power and exhaust strokes, then compares the pistons to bicycle pedals turning a crankshaft instead of a chain.

Try this at home

The rolling can test. With an adult using the can opener, remove both ends of a coffee can, then punch a hole through the centre of two plastic lids with scissors. Thread a rubber band with a weight taped to its middle through both lids and into the can. Roll the can away from you and watch the twisted band unwind and roll it straight back to you.