Algodoo

Here you learn about the velocity distribution of an ensamble of particles, which model a real gas.
It is based on a previous scenario about pressure, see below.
Your task is to run the simulation at different pressures and keep track of the velocity distribution
of the particles: slow ones are red ( count them! ), a little faster ones are orange ( count them too! ),
medium-speed-ones are green( count them ), and the fastest are blue ( count them ).
To be precise, if the velocity v in m/s of a particle is in the interval [0; 0.5] then its color is red,
if its in the interval [0,5; 1] then its color is orange, if its in the interval [1; 2] then its color is yellow,
if its in the interval [2; 3] then its color is orange, and above its color is blue.

After you counted all numbers, draw a diagram with the color at the x-axis and the number at the y-axis.

If your computer is slow, the animation will stir now and then, cause there is really much to calculate
for the computer. The velocities are done by squareroot(vx*vx+vy+vy) for each particle, and the
color-changes are done after each simulation-step.

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old description of the pressure-scenario:
This scene is intended to get insight into the particle-process of heating a gas to increase its pressure.
The heating is simulated by a rotating stick on a motor, which kicks the blue gas-particles.

To measure the pressure, take down the vertical position of the horizontal red bar while the motor is off, for this use the black ruler. Then at higher pressure, you can do it again, so you get the difference of the two lengths, say: dist.
Now multiply dist with 4Newton/m, as this is the spring-constant to get the additional force F, which the faster particles push in average on the horizontal red bar.

To get finally the pressure, just divide F by 9m², as we assume that in reality in three dimensions
we have a quadratic surface of 3m * 3m.

As long as you press the v- or r-button, the motor is driven with the speed, that you can read in the violet box below. To increase or decrease the speed, move the slider with the drag-tool (d) carefully from the middle position ( 0 speed ) to the left or right ( maximal speed ) while the simulation is on.

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tags: velocitydistribution
Geschwindigkeitsverteilung,
Teilchenmodell,
kinetische Gastheorie,
schule
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If you know a trick to speed up the simulation, then please
tell me how to do so, without taking away particles.
Maybe if the colors are only changed after 10 simulation-steps?