A sewing needle will rest upon the surface of water. If powdered laundry detergent is gently sprinklednear the needle, the needle will eventually sink.
2006-09-28 13:09:03 · 14 answers · asked by NYCGirl_14 1 in Education & Reference ➔ Homework Help
It floats because of surface tension if you look carefully you will see the surface level is depressed slightly around the needle.
Soap powder/detergent work as wetting agents - they break the surface tension when they dissolve into the water hence the needle sinks. Someone stole its hammock. Heres a thought.
its impossible to sink a body in the dead sea due to its high salt content would the needle float better (higher in the water)?
2006-09-28 13:18:21 · answer #1 · answered by scrambulls 5 · 1⤊ 0⤋
The needle floats because it is not heavy enough to overcome the surface tension of water, which is very high. The detergent is a "surfactant", a substance that reduces surface tension. See http://en.wikipedia.org/wiki/Surfactant
2006-09-28 20:19:15 · answer #2 · answered by gp4rts 7 · 0⤊ 0⤋
This happens because the surface of the needle as compared to its weight,is not sufficient to break the surface tension.The same applies to a steel aircraft carrier and the like.The weight compared to the area simply won't break the opposing force opf the water.Sprikling anything next to it may cause the same effect causing a break in surface tension
2006-09-28 20:11:30 · answer #3 · answered by joecseko 6 · 1⤊ 1⤋
The water has what is called "surface tension" and it is strong enoght to support a needle.
2006-09-28 20:10:33 · answer #4 · answered by Anonymous · 0⤊ 0⤋
the needle has less mass per area than the water and if you sprinkel anything on the water it will shift the weight distrubition and cause the needle to sink
2006-09-28 20:11:32 · answer #5 · answered by Adam T 3 · 0⤊ 0⤋
ITS NOT HEAVEY ENOUGH TO BREAK THE SURFACE TENSION, POWDER ACT'S AS A UNEVEN PLAIN IN THE WATERS SURFACE, PLUS DETERGENT ALSO ACTS TO BREAK THE ADHESION TENSION BETWEEN NEEDLE AND WATER BOND.
2006-09-28 20:13:11 · answer #6 · answered by hazegrey 3 · 0⤊ 0⤋
The needle, like most other things, is less dense than the water molecules.
2006-09-28 20:10:52 · answer #7 · answered by bryanmantle777 2 · 0⤊ 1⤋
its the same reason why certain insects can float on water,
its because the obect is so thin, it hasn't broken the surface tension of the water. so it floats
2006-09-28 20:11:04 · answer #8 · answered by Anonymous · 0⤊ 1⤋
because the needle is less dense than the water.
2006-09-28 20:17:16 · answer #9 · answered by swim chick 3 · 0⤊ 1⤋
surface tension ring a bell?
2006-09-28 20:10:17 · answer #10 · answered by Kuji 7 · 1⤊ 0⤋