2: The Shadow-Fan Illusion
This illusion can only be seen in the morning (roughly 8-10 am) on a sunny day. Go south from Minor Hall toward Bancroft Avenue. Pass Wurster Hall on your left. Kroeber Hall is approaching on your right.
You’re walking toward Café Strada, a local cappuccino hang-out. You approach vertical rods stuck in the sidewalk. Stop on the Minor Hall side of the rods at a distance of ~10 feet.
Notice the shadows created by the rods. Do they appear to be parallel to one another? Or do they appear to fan out (left ones to the left and right ones to the right)? Most people report that they fan out. They’re actually parallel.
To prove that, you can measure them, but it’s simpler to note that the shadows are created by the sun light, which because the sun is essentially infinitely far away, has parallel rays and therefore creates parallel shadows.Back to Map Next