Thermoabsorption Cans

Demo: TH-B-TA
Pira Index: 4B 40.40

 Lab Equipment  Directions
  1.  set of 3 stoppered cans (attached to circular aluminum tray) with temperature probes
  2. light source with dimmer switch
  3. 3 digital multimeters
  4. 3 thermocouples
  1.  Connect the temperature probes from each can to a thermocouple plugged into a multimeter. Set the thermocouple switch to Celsius and the multimeter to 300mV.
  2. Record the temperature reading from each can.
  3. Center the light a short distance in front of the cans and turn it on.
  4. Wait a few minutes and read the temperature shown on each meter.

Diffusion in Air/Water

Demo: TH-D-DA
Pira Index: 4D 50.10

 Lab Equipment  Directions
  1.  closed jar containing Pinesol (inside cardboard tube to disguise it)
  2. large plastic jar with water
  3. blue or green food coloring
  1.  Set jar with water on the desk. Let all the liquid motion settle down. While waiting, open the cardboard wrapped jar.
  2. Ask students to raise their hand as the class proceeds when they smell the chemical.
  3. With minor disturbance, put a couple of drops of food coloring in the water and observe.

Note – it is best to do this near the beginning of the lecture and check with students off and on during the period.

Thermoconductivity Blocks

Demo: TH-B-TB
Pira Index: 4B 30.00

 Lab Equipment  Directions
  1. 2 black slabs about 4″ square
  2. 2 large o-rings
  3. small dewar of ice.
  1.  Pass the two blocks (the darker is aluminum, the other is coated foam) around the room and have the students notice the observed “temperature difference” between the two blocks. Note that the aluminum block feels cold.
  2. Have the students guess on which block will the ice melt the fastest. Place o-rings on each block and place a few ice cubes inside the ring.
  3. Observe the rate of melting of the ice.

Light the Match

Demo: TH-B-LM
Pira Index: 4B 40.10

 Lab Equipment  Directions
  1.  2 concave reflectors on steel poles (1 with socket and heater, 1 with match holder)
  2. 2 telescope clamps and wood blocks
  3. block with match holder
  4. lab jack
  5. wooden matches
  6. glove
  7. light bulb (60 watt quartz vert. filament)
  1.  The reflectors are left mounted and aligned on the cart. Unscrew the heater and place a light bulb in the socket. The light should focus on the end of a matchhead which is placed at the focal point of the other reflector. When focused, replace heater.
  2. Place another match on the block holder and place it on the lab jack positioned between the two parabolic reflectors. Plug in the heater.
  3. Shortly after the match at the focal point starts to smoke an ignites. The other match does not.

Falling Candle

Demo: TH-B-FC
Pira Index: 4B 20.00

 Lab Equipment  Directions
  1. candle in plastic jar with blue lid
  2. lighter
  1.  Remove lid and light the candle.
  2. Hold the jar up high and let it drop. Catch it before it hits the floor. Notice that by the time you can catch it the flame is extinguished.

option: Drop the candle with the lid closed to show that air currents are not what causes it to go out.

Liquid Nitrogen Demo

Demo: TH-A-LN
Pira Index: 4A 40.30

 Lab Equipment  Directions
  1. dewar with liquid nitrogen
  2. 6 balloons
  3. 10″ tygon tubing
  4. hammer
  5. lead bell
  6. superconductor set
  7. tongs
 Hold each item in liquid nitrogen, then use tongs (if needed) to retrieve the item:

  1. Balloon: Inflate to a diameter slightly larger than the dewar. Set it on top of the dewar and as it cools, push it into the liquid. Retrieve and set it on the table so it can be observed as it warms.
  2. Tygon tubing: Hold one end in the liquid for a minute. Upon removal, hit it with a hammer.
  3. Bell: see TH-A-LB
  4. Superconductor: see EM-G-SC

Rubber Band Contraction

Demo: TH-A-RC
Pira Index: 4A 30.80

 Lab Equipment  Directions
  1.  lab stand
  2. 3 finger clamp
  3. triple beam platform balance
  4. 1000g hooked mass
  5. rubber band (3.5″ x .25″, #64)
  6. heat lamp with socket and clamp
  7. circuit cooler spray can
  8. extension cord
  1.  Set up as shown. Position the 3-finger clamp so that the rubber band tension lets the scale balance at zero.
  2. Plug in the heat lamp and shine it on the rubber band. As the rubber band heats up and contracts, the balance will swing downward.
If you wish to show the opposite effect, you can spray the rubber band with the circuit cooler.

Demo Thermostat

Demo: TH-A-DT
Pira Index: 4A 30.11

Lab Equipment  Directions
  1. demo thermostat apparatus
  2. 4 batteries (total 6V) in holder
  3. candle
  4. matches or lighter
  5. tray
  6. torch
  1.  Put the entire set-up on a tray to catch the candle wax. Connect as shown and the light should come on.
  2. Hold the candle to the bimetallic strip.
  3. As the strip warms up, it bends, breaking contact and the light goes off. As the strip cools, it straightens, remaking the contact and the light comes on.

The light represents the furnace in your house.