Cannons & Walls: In the Microscopic Pressure simulator, cannons fire balls of varying masses and velocities at a sensitive wall to model the phenomenon of pressure. The wall has sensitive hotspots into which you can plug in meters that measure the number of collsions, average impulse per collision, and the total force on the wall. The figure to the right indicates where you hook up those meters. To place the meters, you must click directly on a hotspot.

Each cannon is a separate object. In a cannon's Properties Box, a cannon can be turned on or off. You can set the mass and speed of the balls, as well as the firing rate of the cannons. The velocity direction is determined by the orientation of the cannon, which cannot be changed. Cannons only fire in Run mode.

The firing rate and ball mass and speed each have three settings: low, medium, and high. For ball mass and speed, medium is twice low and high is three times low. For firing rate, high is twice medium and three times low.

The disabled property is the color of the cannon. Although you can enable this property and change a cannon's color, the ball color does not change when you do so.

Cannons cannot be moved, but they can be deleted, cut, or pasted. Be forewarned, though. With no cannon button, you cannot replace a deleted cannon. Once lost, it is gone.