Water Hammer

water hammer


  •  The water-containing flask has been partially evacuated, allowing the water inside to fall as one solid column. (Typically water breaks up as it falls through air, due to drag.) The sound made when the water hits the bottom is quite remarkable.
  • To use: hold the flask vertically with the bulb at the top. Quickly shake the flask up and down once. When the water hits the bottom it sounds (and feels!) more like a solid metal object than a fluid.  In fact, I’m convinced that the flask would break if shaken hard enough, though the information sheet doesn’t caution against it.
  • Located in L02, section D1.


Bernoulli Bag





  • 8 ft long bag requires many dozens of breaths to inflate if held directly to the mouth.
  • But when bag opening is held a short distance from mouth, bag can be inflated with one breath.
  • Bernoulli’s principle can be used to explain how a current of swift moving air can pull a large volume of air along with it. See: P6-7350_DS
  • Located in L02, section D1.

Air flow lift

Bernoulli effect


bernoulli 2

  • When air is blown over the top of a piece of paper, reduction of air pressure creates lift, causing paper to levitate.
  • Fan located in L02, section B4
  • Paper with rod located in L02, section D1

Air-flow levitation

Bernoulli's Principle levitation 1

Bernoulli's Principle suction 1

Bernoulli's Principle suction 2

  • Air-flow around ball causes nonintuitive levitation and stability.
  • A nozzle connected to the air-blower creates a narrow stream of fast moving air.
  • Ball can be levitated directly above air nozzle, or at an angle.
  • When funnel is connected to air hose, air flow around ball creates lift, preventing ball from falling, even when air flow is directed downwards.
  • Blower, nozzle and funnel located in L35. Ball in L02 section A2.

Weight of Air

weight of air 2

Lid of plastic bottle, shown above, is a pump, and can be used to pump air into container.

Place empty bottle on sensitive digital scale and record scale reading. Then pump additional air into bottle and re-weigh.

weight of air 1

  • Bottle and pump located in L02, section B-5.
  • Scale in L35, section D-2.