course Phy 122
Experiment kinmodel_03: Equipartition of energy and the direction of disorder to (increasing or decreasing)Observe the first several seconds of the simulation at the 'slow' default speed. You will see how the particles initially are all moving in or very close to the x direction, with little or no y component. Note the x and y kinetic energies, displayed near the top of the screen.
**The x kinetic energy was generally greater than the y kinetic energy.
Observe what happens to the directions of motion of the particles as they start colliding.
**When one molecule collides with another it completely changes direction abruptly stopping what was its first continuous path.
Observe what happens to the x and y kinetic energies.
**The x kinetic energy is progressing at a higher rate than the y kinetic energy.
Is the system more organized at the beginning of the simulation or after a couple of minutes?
**The system is more organized at the beginning of the simulation. The more collisions there are then the more disorder in the system.
If the x and y kinetic energies were averaged for 100 years, starting a few minutes after the simulation began, which do you think would be greater?
**The x kinetic energy would be greater.
Run the simulation in this manner several times, and each time determine how long it takes before the total y kinetic energy is first greater than the total x kinetic energy. Report your results.
**For a period of ten trials, it took approximately 10 to 20 seconds for the y kinetic energy to surpass the x kinetic energy. This was using the slow default speed.
Now take some data:
Running at the fastest default speed, stop the simulation with the pause/break key every few seconds, keeping your eyes closed for at least 2 seconds before stopping the motion.
Write down the x and y kinetic energies each time.
Do this at least 30 times.
x: y:
438.7 323.6
337.9 421.9
371.8 380.0
308.4 451.4
308.4 448.4
296.5 460.3
344.7 309.4
296.1 468.6
528.9 235.8
289.2 454.8
402.1 350.9
408.6 353.6
275.1 459.6
370.2 389.6
318.4 361.8
407.2 366.1
396.4 338.7
278.0 433.0
385.0 319.1
285.9 438.8
452.2 258.9
329.3 331.4
372.0 333
381.1 339.6
364.1 357.7
347.9 376.0
326.1 403.1
433.9 315.3
445.2 325.4
311.6 446
512.2 250.0
Find the average of all your x and all your y kinetic energies.
Mean = sum(above #'s) / 31
Mean KEx = 365.1
Mean KEy = 374.3
Do you believe the difference in the averages is significant, in that the direction that has the higher average will always tend to have the higher average every time the simulation is run?
**The difference in the averages is not significant and the KEy will not always have the higher average each time this experiment is done because the numbers are too close."