Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne bike tire spinning 
Name: N/A
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
How does time behave near a black hole?


Replies:
I think this is the stroboscopic effect - your eye does not really see the world in a continuous movie, but in snapshots taken maybe 1/10 of a second apart. So it cannot follow the individual spokes of the tire, and tries to associate each image of spokes with the next image it sees - ie. it tries to slow down the rotation as much as possible and about 50% of the time that means seeing it rotate backwards rather than forwards. I am not too sure of this explanation though - I think I have left some things out...

Arthur Smith

I just did a quick experiment with a stationary bike and did not see the effect you are referring to. Of course in this situation the m motion I perceived for the spokes may have been dominated by the observed motion of the rim of the tire. Normally, the dominant motion you would see would be the motion of the tire center relative to the background -- perhaps this leads to the perception of backwards rotation. By the way, the slow response of our eyes makes it possible for us to watch TV (which is actually about 30 complete pictures a second) without seeing it flicker. Each complete picture consists of two "interlaced" pictures so the screen is re-drawn 60 times a second.

gregory r bradburn


Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory