[net.physics] what happens to the tube

RP@MIT-MC (04/14/83)

From:  Richard Pavelle <RP @ MIT-MC>


I saw the following experiment performed: One has a glass tube 
say 6" in diameter. It is suspended from the ceiling on low 
friction rollers so that it can run horizontally on a track. 
Air is forced into the tube on the left and the tube of course 
moves to the right. 

Now, one heats the bottom of the tube so it gets quite hot and 
continues forcing air through the left end of the tube. The 
question is, what does the tube do? Does it move forward, 
backward or remain stationary and why?


		     roller	     roller	      roller
			O		O		O
			|		|		|
			|		|		|
			|		|		|
			|		|		|
			|		|		|
       -----------------------------------------------------

            ---->
       air  ---->		GLASS TUBE
            ---->

       -----------------------------------------------------
                                 ^^^^^^^^^^^^
				    heat