"You can't pass heat from a cooler to a hotter.
Try if you like, you far better notter,
'cause the cold in the cooler will get hotter as a ruler,
'cause the hotter body's heat will pass to the cooler."

Michael Flanders and Donald Swann.
British comic singing duo in their song The First and Second Law, 1964.

Try these "busters" to exercise your brain ... they should help you grasp the concepts underlying the temperature, kinetic theory and the ideal gas law. To gain the maximum effect you should attempt to answer them before looking at the answers!

[1] If the speed of each molecule in an ideal gas were tripled, would the temperature also triple?

Answer

[2] If the temperature of an ideal gas is doubled from 50°C to 100°C, does the average kinetic energy of the molecules double?

Answer

[3] Can you explain if it is possible for both the pressure and volume of an ideal gas to change without causing the internal energy of the gas to change?

Answer

[4] If the atoms in a container of helium gas have the same rms speed as the atoms of a container of argon, which one has the higher temperature?

Answer

[5] If a slippery cork is pushed into an almost full bottle of wine and released it will slowly slide back out. However, if your pour some wine out and re-insert the cork, the cork does not slide out. Why?

Answer

[6] One assumption in the kinetic theory of gases is that the collisions between the molecules and the walls of the container - which give rise to pressure - are elastic, i.e., the molecules rebound with the same speed after colliding with the wall. Suppose that the collisions are not elastic, i.e., the rebounding speed is less than the approaching speed ... how would the pressure of the gas be affected?

Answer

[7] When bubbles rise in a glass of beer should they change in size? Should their speed increase, decrease or remain the same as they rise?

Answer

[8] Which, if either, contains a greater number of molecules, one mole of hydrogen or one mole of oxygen? Which, if either, has more mass?

Answer

[9] I love this question! An instructor is telling a class about the kinetic theory ... he says that the stove in the room is warming the air and, since the temperature of the air is related to the kinetic energy of the molecules, the total thermal energy of the molecules in air in the room increases. That certainly sounds correct ... but one bright student disagrees and convinces the class and the instructor that the total energy does not change, and the student was right! What could that student have said?

Answer

The idea of brain "busters" was suggested to me by Ms. Lilian Jordan of Palm Beach Community College. The problems have been collected from a number of sources over the years, including myself(!) and inspired from ideas in texts such as "Conceptual Physics" by Paul Hewitt, "Peer Instruction" by Eric Mazur, "Physics for Scientists and Engineers" By Paul Tipler, "University Physics" by Hugh Young and Roger Freedman, "Physics" by John Cutnell and Kenneth Johnson, and "The Flying Circus of Physics" by Jearl Walker. I have adapted them to suit my courses.