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My physics teacher told me that there is no such word as suck, as in the sense of drawing gases, or liquid into something. Is this true?
This shows how slippery words can be. There actually isn't any suction or sucking going on in physics. What it is, is a pressure differential. When you "suck" (common usage) you are INCREASING the volume of the cavity you call your mouth (and lungs). This increase causes the pressure inside your mouth to decrease. The difference in pressure of the interior of your mouth and the atmosphere we live in, causes the atmospheric pressure to force liquid up the straw until pressure is equalized. Periodic swallowing keeps the pressure differential in place.
If you had a rigid, leak-proof straw that was longer than 35 feet, you could NEVER get water out of the top of the straw by "sucking" because atmospheric pressure is only great enough to raise it 33.9 feet. Mercury, being denser, would be restricted to a height of 29.9 inches. (Both are plus or minus a bit to account for local variations. That is why in weather forecasts in the US, they always talk about the pressure falling/rising as inches of mercury.)
Hope this helps. Good Luck !!
p.s. In physics, there also is no such thing as centrifugal force, like what is thought of while on a fast merry-go-round.
Dear britz14, When referring to drawing gases etc. the proper term would be suction. Therefore he is correct that suck would not be used. Sue...good luck
who cares. Physics is a part of science, the gayest subject in the world, [sorry to all the science teacher, students, or scientists.]
Thankyou, my physics teacher did not explain it as well as you have. I had a bit of trouble understanding this concept. Britz
I'd say you were filling a vacuum.
He or she sounds like a jerk...
