Category Archives: Heat and The First Law

Mechanical Equivalent Of Heat

Demo code: TH-B-ME
Pira Index: 4B 60.11

 Lab Equipment  Directions
  1. Syringe with special iron shavings inside & attached thermocouple
  2. Fluke multimeter
  3. 80TK temperature module
  1. Connect the 80TK module into the multi-meter as shown.  Plug the thermocouple probe into the module and turn the multi-meter to the mV setting.  Switch the module to °C and observe the temperature.
  2. Shake the syringe up and down 100 times and again observe the temperature.

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.

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.

Heat Capacity

Demo: TH-B-HC
Pira Index: 4B 10.00

Lab Equipment  Directions
  1. 3 funnels and 3 – 10 ml graduated cylinders
  2. 3 metal spheres (brass, aluminum, lead) with attached strings
  3. wooden funnel support
  4. 3 – 400ml beakers
  5. dewar of ice
  6. pan balance
  7. thermometer
  8. food color
  9. large food service tray
  10. paper towels
  11. small coffee pot with hot water
  1.  Set up as shown, but to start, place a beaker under each funnel to catch melted water.
  2. Place the spheres in the hot water and fill the funnels with ice.
  3. Place a drop of food color in each empty graduate cylinder. When the funnel cools, place the cylinder under the funnels.
  4. Take each sphere from the hot water and place it atop the ice in the funnel.
  5. Compare the amount of ice each metal melts.

Note – place the funnels on ice to pre-cool them before time for this demonstration.

Thermodynamics Processes

Demo: TH-B-TP
Pira Index: 4B 70.00

 Lab Equipment  Directions
  1.  Adiabat – Fire Syringe – TH-B-FS
  2. Isochor – Absolute Zero – TH-E-AZ
  3. Isotherm – Boyle’s Law – TH-E-BL
  4. Isobar – Balloon – Large dewar with liquid nitrogen, coffee pot with warm water
  5. tongs
  6. gloves  
  1.  Follow the directions from each of the first 3 demos mentioned.
For the isobar process, blow balloon up to barely fit inside of the dewar mouth. Partially cool it down and notice fit (loose), Let the balloon warm up on top of warm water and check the fit again (it won’t fit dewar mouth).

Thermomobile

Demo: TH-B-TM
Pira Index: 4B 60.00

 Lab Equipment  Directions
  1.  hot water between 122 – 167 degrees Fahrenheit in small coffee pot
  2. beaker or cup
  3. thermobile
  4. three-finger clamp
  5. small lab stand
  1.  Pour hot water into the beaker.
  2. Attach the thermomobile to the 3 finger clamp on the lab pole. The thermobile should set so that the lower arm is nearly horizontal.
  3. Lower the clamp on the pole until the top of the brass wheel is just below the water surface. (Do not immerse the wheel bearing)
  4. If needed give the top wheel a nudge in a counterclockwise direction.
If the wheel bearing gets lowered into the water, remove the thermobile and shake out the water. 

Thermal Gradient Plate

Demo: TH-B-TG
Pira Index: 4B 30.53

 Lab Equipment  Directions
  1.  postcard thermometer plate
  2. 2 nalgene containers
  3. ice 
  4. hot water
  1.  Fill a container with ice water (below 55 degrees Fahrenheit), another with hot water (above 95 degrees Fahrenheit).
  2. Immerse a leg of the thermal gradient plate in each of the containers.
  3. Watch the postcard thermometer change as a gradient develops across the top of the aluminum plate.
  4. Each light spot on the card is equal to the temperature listed on the right.