Mechanics

M-F1 : Balloon in a Jar

Unit

Pressure

Purpose

Illustrate relative pressures, the strength of the atmospheric pressure

Equipment

  1. Glass jar with a neck and a hole in the bottom
  2. Rubber balloon
  3. Rubber cork
  4. A small bucket

Suggestions

  1. With the cork in place, balloon in the jar, ask a student to blow the balloon up.
  2. Remove the cork, blow the balloon effortlessly
  3. When balloon fills the jar, replace the cork
  4. Fill the ballon in 3 with water from the bucket, remove the cork. Watch out!

Discussion

See attached

M-F2 : Hydraulic Lever

Unit

Pressure

Purpose

Illustrate Pascal's principle

Equipment

Model hydraulic lever

Suggestions

  1. Demonstrate the device
  2. Ask a strong student to hold down the larger piston while you push on the smaller.
  3. "Reverse," hold the small piston down while the student tries to push the larger one down.

Discussion

M-F3 : Density Ball

Unit

Density

Purpose

Illustrate the temperature dependence of water density, the Archimedes Principle

Equipment

  1. Density ball
  2. Glass water reservoir
  3. Small water heater
  4. Thermometer
  5. Water bucket (also, ice cubes)

Suggestions

  1. Ask a student to "check the ball out," ask whether it would float in room temperature water. Try it.
  2. Cool the water to T<15 C (60 F), float the ball
  3. Heat the water to T>29 C (85 F), try to float the ball 

Discussion

See attached

M-F4 : Venturi Tube

Unit

Bernoulli's Principle

Purpose

Classical illustration of the relationship between the speed and the pressure

Equipment

  1. Venturi tube [a tube with short side-tubes avail. only]
  2. Water pump and tubing [NYA]
  3. Water dye

Suggestions

  1. No flow
  2. Flow at a slow rate
  3. Flow at a high-rate

Discussion

  1. Set up
  2. Pouring liquid
  3. Creating low or high pressure system
  4. Results from a slow rate
  5. Results from a high-rate

M-F5 : Magdeburg Hemispheres

Unit

Pressure

Purpose

Classical demo of the force due to pressure difference

Equipment

  1. Small Magdeburg hemispheres
  2. Portable vacuum pump [NYA]

Suggestions

  1. Pump the air out just so the sphere holds together, seperate the two parts with ease
  2. Pump the air out to minimum pressure. Ask a strong student to seperate the hemispheres

Discussion

M-F6 : Equilibrium Tubes

Unit

Pascal's Principle

Purpose

Classical illustration of the liquid-level in connected vessels

Equipment

  1. Equilibrium tubes
  2. A stand
  3. Container with water (plus dye), red wine, oi....
  4. Funnel

Suggestions

  1. Fill with water
  2. Fill with other liquids (predictions?)

Discussion

M-F7 : Mariott Tube (comp. M-K2)

Unit

Bernoulli's Principle (Kinematics in 2-Dim)

Purpose

Interesting evidence of the Bernoulli's Principle

Equipment

  1. Mariott Tube: a cylinder with three holes (stoppers)
  2. Base pan & stand for the tube
  3. Pitcher for water

Suggestions

Holes are numbered 1-3 from bottom to top.

  1. With 1 and 2 open, ask for prediction and run
  2. With all open, ask for predictions and run
  3. Explain

Discussion

See attached

  1. Equipment and set-up
  2. Filling the tube to the brim
  3. Stoppers removed, liquid level continuously maintained
  4. Close-up of the streams: top and bottom arrive at the same point, middle stream goes farther

M-F8 : Adhesion Disc

Unit

Liquid Surface

Purpose

Illustrate the strength of the cohesive force

Equipment

  1. Adhesion disk with harness
  2. Small glass container
  3. Sensitive spring scale

Suggestions

  1. Try with water
  2. Try with another liquid (e.g. cooking oil) In each case measure the force required to extract the disk from the water

Discussion

Adhesion Disc

M-F9 : Atmospheric Pressure

Unit

Fluids

Purpose

To demonstrate atmospheric pressure

Equipment

  1. Scale
  2. Atmospheric pressure demonstrator

Suggestions

Have a strong student pull up on the scale, it takes well over 100N of force to dislodge the plate. 

Discussion

  1. Scale at 0 N
  2. Scale at 60 N
  3. Scale at 100 N

M-F10 : Bell Jar

Unit

Fluids

Purpose

To demonstrate air pressure

Equipment

  1. Pump
  2. Bell Jar
  3. Marshmallow or Shaving Cream

Suggestions

  1. A small amount of vacuum grease should be used on the plate.
  2. The shaving cream goes a long way, use a small amount.

Discussion

1. Equipment
2. Shaving Cream
3-5 Expanding as pressure decreases
6. Maximum expansion
7.  Collapse as the vacuum is released

M-F11 : Bell in a Jar

Unit

Fluids

Purpose

To demonstrate that sound does not travel in a vacuum

Equipment

  1. Power supply (with wires)
  2. Pump
  3. Bell in a jar apparatus

Suggestions

  1. Do not use vacuum grease on either the jar or the plate. 
  2. Works with any lab pump, however if using a lighter pump some sound will still be audible.

Discussion

  1. Equipment
  2. Bell in the jar

M-F12 : Cartesian Diver

Unit

Fluids

Purpose

Illustrate the relationship between volume and boyancy

Equipment

  1. Bottle with water
  2. Cartesian Diver
  3. Cap for bottle

Suggestions

Discussion

  1. Diver at the Top
  2. Diver at the Middle
  3. Diver at the Bottom

M-F13 : Density Paradox

Unit

Density

Purpose

To show the variation of density with temperature

Equipment

  1. Density Paradox bobs
  2. Two beakers, one filled with hot water the other with cold water

Suggestions

Use hottest and coldest water from tap

Discussion

  1. Equipment
  2. Sunken Mass
  3. Floating Mass

Manual Pages:(1)

M-F14 : Magnus Effect

Unit

Bernoulli's Law

Purpose

  1. 2m Pasco Track
  2. Cart
  3. A Fan
  4. Bernoulli's Principle Accessory With String

Suggestions

  1. Hold on to the accessory while spinning it.
  2. Hold the fan parallel to the accessory.

Discussion

  1. Equipment
  2. Spinning up Bernoulli's Accessory on a cart
  3. Bernoulli's Accessory spinning on cart
  4. The cart moving down the track
  5. The cart farther down the track
  6. Still farther down the track

M-F15 : Feather and a Farthing

Unit

Gravity

Purpose

To illustrate the mass independence of gravitational acceleration

Equipment

  1. Feather
  2. Genuine British Farthing from 1878
  3. Pump
  4. Tube

Suggestions

Works best with the high vacuum pump. The stopcock can be used to close off the tube.

Discussion

  1. Equipment
  2. Farthing Heads
  3. Farthing Tails
  4. Falling through air (farthing wins!)
  5. Pumping out the system
  6. Falling through vacuum (it's a tie!)
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