2C20.30 Floating Ball

A ball is suspended in an upward jet of air.Then tilt hose so ball is no longer over end of hose. Even though air is blowing it sideways and gravity is pulling it down the ball may stay in place if ball weight matched to strength of air stream. Equipment provided will differ from that shown below.

Setup Requirements: Minimal. Experiment with matching ball to various air supplies.

Equations: Physicists are still arguing about whether this is due to Coanda effect or Bernoulli equation..

Safety Issues: Don't look into air supply.

2C20.35 Funnel and Ball

Support a ping pong ball by air streaming out of an upside-down funnel..

Setup Requirements: Use mouth or air supply.

Equations: Arguments continue as to whether this is due to Coanda effect or Bernoulli equation.

Safety Issues: Clean funnel before using.

2C20.40 Lifting Plate

A flat piece of cardboard with a tack in it is placed over the end of a hose(blowing air out) with the sharp end of the tack in the hose. The piece of cardboard will stay on the end of the hose rather than be blown off. 

Setup Requirements: Minimal

Equations: Coanda effect or Bernoulli equation, the arguments continue.

Safety Issues: Don't look into air supply

2C20.45 Bowling Balls 

Demonstrate variation of pressure with velocity in fluids. Hang two bowling balls from metal rod so they are a few inches apart. Use a leaf blower to blow air between them. Which way will they move?

Setup Requirements: Assembled as needed. Ask ahead of time. Requires cart with holes for rods.

Equations: Explanation still uncertain: Coanda effect, Bernoulli's equation, other.

Safety Issues: Avoid dropping bowling balls.

2C20.60 Curve Ball

Use a "u" shaped launcher to throw curve balls. Practice this before trying in class. Sometimes you get a noticable curve to path of ball, sometimes not.

Setup Requirements: Off the Shelf

Equations: None

Safety Issues: Hitting people and equipment with balls.

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Use device to produce smoke rings. The ring has a low pressure area at the center. Compare to hurricanes. Useful as attention getting device. 

Setup Requirements: Minimal. Use "Fog in Can" instead of real smoke to avoid setting off fire alarm.

Equations: None

Safety Issues: Do not aim at students.

2C50.30 Vortex

Demonstrate a vortex like a tornado. Swirl the filled upper bottle. As the fluid drains out you will get what might be called a tornado in a bottle.

Setup Requirements: Minimal. Use food coloring to make fluid easier to see. Fill a 2 liter soft drink bottle with water. Connect to empty bottle with device from Arbor Scientific.

Equations: None

Safety Issues: Possible problem with water getting on desk top. Keep away from electronic devices.