Due to the small number of particles in our system it would
take a very long time for a liquid droplet in a tube to reach
thermal equilibrium. To reduce the time of this activity, we will
explore a movie of the simulation.
Your objective is to:
Understand the principle of how a thermometer works in terms of
molecular motion.
You will be able to:
Explain how a thermometer works in terms of molecular motion.
Explain why the column of liquid goes down as temperature is
decreased.
1. Open SMDPlayer, select Galileo-Thermometer in the
IdealGas folder. Press Play.
The movie pauses at the opening
frame and displays the first explanatory caption. In order to
better visualize the particles, you can select Edit
: Background White. The narrow column on the screen represents
our thermometer tube, blue particles represent air molecules, and
the green layer represents a liquid droplet.
2. Press Play to resume the movie. The movie pauses at each
explanatory caption. Repeat this step until the end of the movie
is reached.
At a given temperature,
the droplet fluctuates around a certain equilibrium position. Each
time the temperature drops in our simulation, the equilibrium
position of the green layer also drops. Near the end of the
movie, we simulate the effect of the thermometer inserted into an
extremely hot environment: everything is thrown out of the tube
and your thermometer breaks!
Q2.34: Describe the relationship between the height of the gas
sample and the temperature. Explain how the thermometer works in
terms of molecular motion.