Motion of air molecules
Java-Applet of Fu-Kwun Hwang.
http://www.phy.ntnu.edu.tw/java/index.html

Imagine the motion of gas molecules in the air surrounding us.

• Please note : this is a slow-motion and a huge enlargement of the real atom or molecule size!

• Every circle represents a gas molecule in the air. Certainly there are several sorts of them.

• Zahl defines the total number of molecules in the chosen box.
  Enter a value in this field and press RETURN.

• m₂/m₁ is the mass relationship of the big red sphere to the smaller grey spheres (= molecules). Enter different values and find out, what happens, when this mass ratio changes!

• Pressing + makes the motion faster.
  Press - and they will become slower.
  
  
• Acitivate or deactivate "Bahn" and you will see or switch off the trace of the big red molecule.
  
  
• If you click with the right mouse button, you stop the animation and you can drag the red molecule by hand. If you click again, you restart the animation.
  
  
• If you choose "Noboundary" the molecules will behave as if there were no wall (no reflection) like in real air.