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Concrete Wheel

Age 11 to 14 Challenge Level:

Alan Schoenfeld reports that:

Some people think that the room will go (almost) instantaneously dark as the wheel first passes the window, that it will stay dark for a short while and then go (almost) instantaneously light as the wheel leaves.

Others think that the room will go (almost) instantaneously dark as the wheel first passes the window, that it will stay dark for a relatively long time and then go (almost) instantaneously light as the wheel leaves.

Others think that the room darkens slowly, as though a large curtain is being pulled, more or less horizontally (from left to right), or diagonally (from the top left corner), or vertically downwards, as in the sketches below:

possible views
The room then stays dark for a short /long period of time, after which it lightens in a way that is complementary to the way it darkened.

What do you think?

Perhaps this interactivity can help:

You can make the wheel bigger and smaller by pressing the up and down arrow keys and you can make it roll by using the other arrow keys. You can also move the blue square around.

Full screen version