Your rubber band gun is loaded with potential energy.
Are you the sharp shooter in your family? Do you know how to release the band to give it just the right amount of distance, speed and sting? Maybe you have a natural knack and quick trigger finger, or maybe science is on your side. We all know rubber band guns are great fun for leisure time, but they can also be an entertaining way to teach a little physics lesson about potential and kinetic energy to young ones.
Rubber band guns work similar to a Jack in the Box. When pulled back on the cog of the gun, the rubber bands hold potential energy, much like the springs of a Jack in the Box when the lid is closed. When the band is released, it displays kinetic energy, similar to when the Jack in the Box is opened, the springs are released and the clown is pushed out of the box. How far the rubber band flies depends on how much potential energy is stored in it. The potential energy is affected by how far back the band is stretched out. The further it is stretched, the further it will fly, because there is more potential energy stored up in it.
For a fun and educational activity you can do right outside your front door, find a buddy to help you and an open stretch of sidewalk. Grab your rubber bands, some chalk (or anything to mark your shots), paper, a pen, a ruler and a tape measure.
Pick a stretch of sidewalk where you won’t hit anyone or anything. A long driveway could work too, as long as there are no cars parked in the way.
• Once you’ve found your spot, mark a line on the sidewalk. This is where you will stand and shoot from, as well as where you will measure the distance of your shot.
• Before you start shooting, have your helper stand to the side, but in an area where they can see where the rubber band lands.
• Ready. Aim. Fire! Shoot a rubber band by hooking it on the front edge of the ruler, then stretching it back to the 10 centimeters (cm) mark on the ruler and letting the rubber band go. Remember the angle and height at which you hold the ruler because you will need to keep it the same for each rubber band launch.
• Have your helper make a chalk mark where your rubber band landed. Repeat shooting from this length with at least 4 more rubber bands to get a grouping. Make sure your helper marks where each band lands. From your shooting line, measure the distance with the tape measure and write it down for each band.
Repeat this process shooting the rubber bands from 15 cm, 20 cm, 25cm and 30 cm marks on the ruler. Are all of your bands from each group landing close together or is there variation in where they fall?
If you want, you can average your results for each stretch length and make a graph of your findings. Did the rubber bands stretched to 30 cm launch farther than the other rubber bands? Did you see a linear relationship between the launch distance and stretch length when you graphed your data?
You can get an idea of your average shot distance with your rubber band gun, by measuring the distance from the front of the barrel to the cog where the band will be released. Knowing this allows you to poise yourself to make a successful shot every time, giving you the advantage against your opponent.