Volume 16

A positive refractive index gradient at an ethanol/water interface in a small glass tank models similar positive refractive index gradients created by a layer of warm air above a calm sea. Inferior mirages (omega and hourglass sunsets) are simulated and photographed as the interface slowly diffuses. Island mirages, made with small silhouettes placed in the tank, complete the simulation of an inferior mirage sunset seen in the atmosphere.

The bounce of a basketball against the ground was recorded using a high-speed camera. The effect of the total deformation of the wall of the ball on the energy loss during impact was studied for impact speeds ranging from 3.2 m/s to 14 m/s. It was found that the energy loss increased non-linearly with increasing total wall deformation.

The relationship between the angle of a spinning glass disc and its rate of axial precession was investigated. The spinning disc was recorded with a high-speed camera and the angle and rate of precession of the disc determined using video analysis. The behaviour of the disc was compared with a theoretical model. It was found that the rate of axial precession of the real disc deviated slightly from the predictions of the theoretical model.

A sustainable alternative to bubble wrap to protect items during shipping is needed. The suitability of using loofah was explored. The cushioning effect of loofah during collisions was measured using a metal cart and varying layers of loofah. The maximum deceleration of the cart during the collision was determined. Increasing the number of layers of loofah showed a strong inverse relationship with maximum deceleration upon collision compared to layers of bubble wrap.