Push-Pull (Move Top Wall) Tool: This tool simulates an external force being exerted on the movable wall (the piston). The external force can be either a push or a pull, and may be due to a person or machine either pushing  the movable wall in, or pulling it out. 

The push-pull tool may be used with either the constant temperature or no heat transfer (adiabatic) options for the heater/cooler element.  You cannot use the push-pull tool in conjunction with the gas tank, the vacuum pump, or the heater and cooler options for the heater/cooler element. 

To place the push-pull element, depress the push-pull tool button and click once on the gas container. 

To push down or pull up the movable wall, click on the appropriate radio button (Figure 1, Figure 4), and then click Run (you can also click Run first). The option you don't choose is grayed out, and an arrow appears above the container indicating the direction and magnitude of the applied push or pull (Figure 2).  Click the Return button (Figure 2) to move the top wall back to its original position. Both the push and pull options are grayed out while the wall moves back (Figure 3).  Once the top wall returns to its original position, you may again choose to  pull up or push down the movable wall (Figure 4).