Overhead Projector, Petri Dishes and Water, Digital Thermometer & Probe

 

Code Number: 4B40.60

Demo Title: Infrared Radiation - Sensitive Thermocouple and Overhead

Condition: Good

Principle: Infrared Radiation

Area of Study: Thermodynamics

Equipment: 

Overhead Projector, Petri Dishes and Water, Digital Thermometer & Probe

Procedure:

Place a thermometer with a blackened probe tip directly on an overhead projector. Turn on the projector and observe the temperature of the probe after three minutes. The temperature should be in the range of 97 to 100 degrees F. Now put the petri dish filled with water between the probe and the overhead projector. Within two to three minutes the temperature should have fallen to 91 to 93 degrees F. (Water is absorbing a majority of the infrared radiation.)

References:

  • Dean Zollman, "Absorption of Radiation - A Lecture Sized Demonstration", TPT, Vol. 12, # 9. Dec. 1974, p. 563
  • Robert Ehrlich, "7.2 - Heating Black and Silvered Bodies", Why Toast Lands Jelly-Side Down, p. 116-118.