We've all seen a spoon apparently 'bent' by a glass of water; and many of us have been taught that refraction – the bending of light by water – is responsible. Care to explore this further? Gather a penny; a glass jar, a beaker, or a cylindrical drinking glass with vertical sides; and a tray or similarly flat item that can hold water (such as a glass baking dish, a plastic sandwich container, or a box-style picture frame).
Begin by putting the penny in the middle of the baking dish. Set the beaker on top of the penny. Look down at the penny at a diagonal angle through the side and bottom of the beaker. Now slowly fill up the beaker with water, watching the penny through the side of the beaker all the while. What happens?
Next, pour a small amount of water (just enough to be perhaps a quarter-inch deep) into the baking dish. What do you see now when looking through the side of the beaker?
I'll give you a day or two to carry out the experiment before telling you what I see when I do this activity. And then, a day or two more to develop - and test - some theories for what you see.
Copyright 2009 Joshua Roth.