I was helping one of my kids with some physics homework today and needed a simulation of projectile motion. I remembered a nice set of physics simulations I had used a few years ago. I typed “physics simulations” into Google and the site was at the top of the list.
Physics Education Technology (PhET) is a set of simulations created by the University of Colorado. I first used the Circuit Construction simulator to show a student how to setup a wheatstone bridge. This isn’t the most complicated circuit in the world, but it requires half a dozen different parts. One of the resisters needs to be adjusted in real time and that is where the simulator was invaluable.
Tonight I needed a ball traveling at 10 m/s straight off the edge of a table 1.0 m tall. I could have setup a video camera (recording at 30 frames per second) recording a tennis ball rolling off the edge of the kitchen table, but I would have never been able to get the ball going exactly 10 m/s. Plus, I would have had to dump the video to the computer before we could do any real analysis.
The projectile motion simulator at PhET was perfect. We were stuck with using a cannon, but could adjust to the starting height and angle to match our needs. We could also project a golf ball, baseball, bowling ball, pumpkin… even an old Buick. The sim includes a tape measure to make measurements after the experiment.
All the extra tools were great, but I really only needed to show that the X and Y components of motion are independent. We shot the ball at 10 m/s and 1 m/s. Both times the ball took the same amount of time to fall to the ground. The faster shot went out farther, but still took the same time to drop from the table to the ground. After using the simulation with different settings, I could tell the light had come on.
Physics is more fun with you blow things up, but this simulator did the trick today.