The purpose of this experiment was to find the effect of different chamber and barrel
lengths of a potato cannon on the distance and velocity of a potato’s travel. It was hypothesized
that the if the size of the chamber and barrel increased, then the distance and velocity would also
increase. This hypothesis was developed due to the knowledge that if there was a larger area for
combustion to occur then more expanding gas would be created to propel the potato forward and
out of the barrel.
The device used in this experiment, known as a potato cannon, is made of three main
components, the chamber, the barrel, and the ignitor. The fuel for the reaction is dispersed into
the chamber, or base, of the cannon. The chamber of a potato cannon is a wide piece of PVC
piping where the initial reaction occurs. Connected to one end of the chamber is an ignitor of
some sort, either flint or gas, which will be responsible for initiating the chain reaction. On the
opposite end of the chamber is another length of PVC. This is the barrel, which is of a smaller
diameter than the chamber and contains the projectile. These two pieces of piping and the
ignitor are the key elements of a potato cannon.
A firearm operates on the simple principal that when the fuel is ignited, the temperature
of the air and fuel mixture in the chamber will increase, causing the mixture to expand. Since
this is a contained reaction, the gases must exit through the barrel, causing the ammunition (the
potato, in this case) to be propelled in the same direction. (Add elaborating sentence)
In addition to the chamber, barrel, and ignitor, there are a few other important parts in
the potato cannon and its operation. The basis of the cannon is PVC piping and connectors to
join the piping, containing the reaction. The cannon is operated using a propellant, in this case
propane, and a projectile, a metal slug.