Question

Why (if you are careful) are you able to float a needle on the surface of water? the surface tension that is a result of water's cohesive properties makes this possible. the covalent bonds that hold a water molecule together are responsible for this ability. the polarity of individual water molecules makes this happen. water has adhesive properties. a single needle is less dense than water?

Answer 1

The correct answer is: the surface tension that is a result of water's cohesive properties makes this possible.

Surface tension is a phenomenon that occurs when the H2O molecules at the surface act different then other H2O molecules. Those on the surface have stronger attractive forces between them, because they have no neighboring molecules above them. So, the surface tension can be defined as the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature.

Answer 2

The surface tension of the water is the reason behind the floating needle. This surface tension is a result of the cohesive properties of the water. The water molecules have cohesive forces acting on them from all the sides. However, the water molecules at the top most layer does not experience these cohesive forces from the top. This led to a sheet (imaginary) formation. This is what keeps the needle floating as the needle does not exert enough force to pass through this fictitious sheet.

Hence, the answer is 'the surface tension that is a result of the cohesive properties'.