How a Steam Engine works

Inside a steam engine steam is produced  by boiling water the pressure of the  expanding steam is used to push a piston  to and fro in a hollow tube called a  cylinder. The piston fits tightly inside  the cylinder the piston is attached to the piston rod as the piston rod goes in  and out it drives another rod called the  driving rod the driving rod turns a  wheel called the flywheel which turns  steadily even when the piston is at the  end of its stroke and is not pushing