Why is it that a needle will float on water and sink when a detergent is added?
1 answer
A needle will float on water due to surface tension, which is the property of a liquid that allows it to resist external forces. When detergent is added to water, it decreases the surface tension of the water, causing the needle to sink. This is because with lower surface tension, the water molecules are not as tightly bound together and the needle is able to break through the surface and sink.