A student in Intro asked about why when you are looking at
the wheels of a moving car it can sometimes appear that the
wheels are turning in the opposite direction of the car's
movement. I have heard an explanation of this kind of
phenomenon when viewed in a film or under artificial
lighting that relies on having a rotation rate that is a close
match to the flicker rate of the artificial light. However,
I can't explain why it would occur under natural light.
The sun doesn't have a flicker rate. Can anyone
help me with this question?
Richard Platt
St. Mary's College of Maryland
