I like to use optical illusions for warm-ups and bell ringers, to get students thinking and looking at things a bit differently.
What’s the illusion? Well, you see those green stripes? See the blue stripes? Actually they are the same color.
You don’t think so? Zoom in. Or click over to Wiseman’s blog site and see what happens when all the other colors are turned to black.
I know you think you know what you see; what you think you see may not be what you actually see. Your brain modifies what you think you see, in order to make it appear sensible, and in doing so, it sometimes makes you see things quite differently from what they are. Don’t forget that.
So, how do we know what we know? How do we know that what we know is correct?