University of Queensland academic Stephen Hughes found that entries for the word 'siphon' incorrectly said atmospheric pressure is the force that allows the device to move liquids from one place to another.
"It is gravity that moves the fluid in a siphon, with the water in the longer downward arm pulling the water up the shorter arm," he said.
"An extensive check of online and offline dictionaries did not reveal a single dictionary that correctly referred to gravity being the operative force in a siphon," he added.
Looks like the new version of the dictionary will have the corrected definition. Good for him!
Now let's see if someone else can find other errors. Wikipedia doesn't count, because there's already too many! :)
Edit: more coverage of this at PhysOrg.
Zz.
What does he mean when he says "with the water in the longer downward arm pulling the water up the shorter arm" ?
ReplyDeleteIsn't the pulling force created by the difference in atmospheric pressure made when the water goes down the longer arm (vacuum effect)? And so atmospheric pressure would in fact be the force that pushes the water in the shorter arm, while gravity pulls the water down the long arm, making the definition not erroneous but rather incomplete.
I'm no physicist so if i'm wrong please explain.
I agree with Alphonse. See the website at SiphonPhysics.com
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