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Old 03-03-2007, 06:11 PM
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strongmanmike (Michael)
Highest Observatory in Oz

strongmanmike is offline
 
Join Date: May 2006
Location: Canberra
Posts: 17,689
Quote:
Originally Posted by Photon View Post
A very good example of what the mirror feels is to hold your mouth 1" (25mm for those into metrics) or so from the back of your hand and blow firmly, then reverse this and suck hard. It's very obvious what you would do to cool things. For those that don't have air-conditioning at home, remember we usually stand in front of a cooling fan, not behind it.
Regards IanG
Is that a good comparison though? Your hand is damp and thus you feel the cooling effect due to evaporation.

Besides if you cup your other hand into a cylinder then hold it just off your other palm and blow through that, then compare it to sucking the differece is much less obvious. The cupped hand is rather like the back of my scope as the air, if sucked, would enter around the perifery of the back plate and move across the mirror and out through the fan (my mouth)...

It's also hard to compare becasue your breath is warmer than the surrounding air so doing the cupped thing means that blowing delivers warm breath air onto my palm while sucking pulls cooler air across my palm...?

Still no answer....

Mike

See? still confusing

Mike
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