Grade 8 has been studying energy and forces. In the photo, our students are measuring the mass of a tennis ball. They will use this data to calculate the gravitational potential energy (GPE) of the tennis ball when dropped from various heights. Later during the lab, they will use an online calculator to determine the ball’s energy at impact. Since the initial GPE and the energy at impact are roughly equal, they will have used mathematics to provide evidence for the law of the conservation of energy.