Category Archives: Electromotive Force & Current

Thermo-Electric Converter

Demo: EM-E-TE
Pira Index: 5E 50.12

 Lab Equipment  Directions
  1.  Thermo-electric converter
  2. two styrofoam cups
  3. ice water
  4. small coffee pot with hot water
  1.  Fill one cup with ice water; the other with hot water.
  2. Place one leg of the converter in the hot water; the other in the ice water as shown.
  3. Wait a few moments for the temperature of the legs to change. Watch the fan begin to rotate (it might need a slight nudge to get it moving).
  4. Now mix the water in the two beakers so that they are both at approximately 50 degrees Celsius. There is still the same thermal energy, but now the fan won’t turn.


Chemical Cell

Demo: EM-E-CC
Pira Index: 5E 40.25

 Lab Equipment  Directions
  1.  Potato clock
  2. Potato
  3. Citrus fruit
  4. Special probe set (Cu/Zn ends)
  5. Fluke 75III digital multimeter OR large demo multimeter
  1.  For the clock, put the probes into each half of a potato and the clock should give a time read-out. If it doesn’t work check if there appears to be a zinc coating still on the nails. If so replace the probes in a slightly different spot on the potatoes. It not, new galvanized nails are needed.
  2. For the fruit, push the special probe ends into the fruit. Connect the other ends to the meter and set the meter to read volts. Take the reading.