Volume 1

The diameter of craters formed by spheres of varying mass dropped into sand at low speed was studied. The relationship between the diameter of the crater formed and the kinetic energy of the projectile at impact was found to be of the same general form as that for planetary meteor craters. The relationship is shown to be a power law with exponent 0.17.

The coefficient of restitution (COR) of a tennis ball was investigated over a range of impact velocities. It was found that the COR of the ball was lower than ATP regulations specify, and that the COR decreased with increasing impact velocity.

In 2005 Paul McKeag, conducted a series of experiments on vortex rings in air. Video of an air vortex traveling through air over a distance of four meters was analyzed using Logger Pro to find the velocity of the vortex as a function of the distance traveled. In a separate series of measurements, the impulse delivered to a force plate by a vortex at different distances was measured and the result was used (with the velocity-distance data) to find the mass of the vortex as a function of distance.

The relationship between belt speed of a Van de Graaf generator and the parking length was investigated. The speed of the belt was varied from 1.6 to 8.8 m/s and the maximum distance of spark discharge recorded. The maximum discharge distance was shown to be proportional to the square root of belt speed.