Physics 132 Week 8
Applying Thermodynamics
Adiabatic Cloud Creation
Show your students how adiabatic processes cause a quick change in temperature by creating a cloud right in front of their eyes! Make sure you have a little bit of water in the flask before inserting the match, and Do Not Use Alcohol!
Work and the "PV" Diagram
Using this simple piston you can provide a concrete example of what happens during various stages of the work cycle on a pressure vs volume graph. Make sure to press down firmly on the white clamp, or your system won't be isolated!
Conduction
Thermal Conduction Rods
Your students can feel conduction by holding onto metal bars as you blow torch them on the opposing end and timing how long it takes them to heat up one at a time, or by feeling which one gets hot first if holding them both in separate hands. **Have a water bath to dunk rods nearby**
Convection
Chimney Model
This demonstration is nothing more than a small chimney. Without the vane to allow air circulation the flame burns out. Once air is circulating you can blow out a match and bring it close to the tube, the smoke will then follow the convection current!
Convection Tube
By following some colored dye in water, you can show students that fluids convect. You can even reverse the flow direction by transferring which side of the tube the heat source warms.
Radiation
Crook's Radiometer
The vanes on the radiometer are colored differently on each side. The black side will heat up more rapidly than the white side causing the vane to spin. See if your students can explain why the vane rotates knowing that it is not an example of the photoelectric effect.
Parabolic Reflector
Use this demonstration to show your students that radiation is a form of energy transfer by igniting a match using the IR radiation of a projector. **This demonstration is extremely bright. Bring sunglasses and tell your students not to stare directly into the focal point.**