Changing the shape of the lens in human eye model

 Using the @pascoscientific adjustable lens in the human eye model and with ray boxes. Its great to be able to show the biology and physics students how the human eye lens works getting thicker and thinner rather than using fixed shaped lenses. #iteachphysics #teaching

The lens consists of two sheets of plastic with water in the middle and connected to a syringe. If water is pushed into the eye the lens gets fatter and becomes convex in shape. As water is removed the lens becomes concave in shape.. Adjusting the amount of water changes the dioptre of the lens. Fascinating to watch and use.