Conservation of Energy - Pendulum

This is a very simple lab that is very good at helping to get an understanding of the conservation of energy. In the classroom before going into the lab the instructor and the students examine a simple pendulum system. The students are asked if the pendulum is raised a vertical height, h, above a reference point and then released what is the velocity of the pendulum when it passes through the reference point during its pendulum motion. The students and the instructor work together as a whole to come up with the theoretical velocity of the pendulum using energy methods. The students are then asked to figure out how to measure this in the lab. They come up with using the photogate timer system that has been used previously. The groups go into lab and perform this experiment anyway they choose. They measure the experimental velocity five times and determine its mean and standard deviation of the mean. This result is then compared to the theoretical result obtained earilier in the lab.

This lab is simple but it helps them to observe about a reference point (actually any point could have been selected as the reference point) for the potential energy being zero. They figure out that the reference point is the height of the photogate timer. They need to be careful in measuring the vertical height h. The students comment that this is a good simple lab.