Steam engines were the backbone of the industrial revolution.
In this common design high pressure steam is pumped alternately
into one side of the piston, then the other forcing it back and
forth. The reciprocating motion of the piston is converted to useful
rotary motion using a crank.
As the large wheel (the fly wheel) turns a small crank or cam is
used to move the small red control valve back and forth controlling
where the steam flows.
In this animation the oval crank has been made transparent so
that you can see how the control valve crank is attached. Next
