hi every1
i have a little question here, when a pice of paper is put on a half full glass of water and the glass is flipped, the paper doesn't fall, why??
well i know if the glass if full, the paper doesn't fall because the pressure of water acting on the paper is less than that of air, but when it's half full three pressures act on the paper, two from inside the glass (air and water), and air from outside the glass, which -i think- makes the pressure of air and water inside the glass more than the pressure of air outside the glass..
can u give me a detailed explination plz..
thanks..
2006-10-28 08:34:44 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Physics
can it b explained in a more simple way?
2006-10-28 08:53:56 · update #1
The air left above the water when the glass is inverted would have to leave a partial vacuum above it if it were to move toward the water - this fact alone makes it unable to provide any additional pressure to aid the water in overcoming the air pressure pushing against the paper.
2006-10-28 08:46:39 · answer #1 · answered by LeAnne 7 · 1⤊ 0⤋
the wet paper forms a seal around the rim of the cup. This becomes a contributing factor. the air in the cup is a lower pressure then the outside air as a result of the water cooling it down. As a result, the higher pressure of air outside the cup wins and holds the paper in place.
2006-10-28 23:37:50 · answer #2 · answered by sirus3810 3 · 0⤊ 0⤋
miniscus plays in here. The water that initially wets the paper forms a "gasket"
of sorts. As more water wants to get through that gasket, a bead builds up with more PSI than the downward force of the water in the glass.
2006-10-28 15:59:26 · answer #3 · answered by Anonymous · 1⤊ 0⤋
she's right, but too sophisticated.
2006-10-28 15:50:32 · answer #4 · answered by Anonymous · 0⤊ 0⤋