Model eye demonstration

I’m currently in the mist of teaching GCSE Extension Physics (in particular Edexcel’s P3) and there are lots of nice optics in there. In particular about the eye. I strongly feel that the students would understand how each part of the eye works by doing a dissection but alas we currently do not have the budget for this. Next best thing a model… not just a plastic one.

Model of the eye

So how does this work? Well that is 4 litre flask (with some Fluorescein in) that has a beam of light from a ray box (would work better with a more directional source) and lenses on the front. You could put various on at once but I decided it was best to just do one at a time. By using different focal length lenses (representing the cornea+lens) you are able to show different vision defects. The paths of light are clearly visible. We then used different lenses in front of the model to show how the beams of light are altered. Basically we mimicked what an optician would do – giving a nice How Science Works link.