Question

It is possible to balance a paper clip on the surface of water in a beaker. If you add a bit of soap to the water, however, the paper clip will sink. Explain how the paper clip can float and why it sinks when soap is added

Short answer

Yes, it is possible for a paper clip to float on the surface of water due to the effect of high surface tension with much higher density.

Step-by-step solution

Explanation regarding paper clips float on the surface of water

Paperclips appear to float when suspended on the surface tension of water. Cohesive force is the main reason regarding the surface tension of the liquid molecules. Water molecules bind together on the surface of the water acting like a “skin” This phenomenon is considered to be the surface tension of water. The cohesion force between the water molecules is much stronger than the attraction of the water molecules to the air. As a result, it becomes very difficult to move an object through the surface so the paper clip floats.

Explanation regarding paper clips sink in water

If a bit of soap is added with the paperclip it will sink. According to the properties of the surfactants soap can bind to both polar and nonpolar substances. So, it will bind with polar substance water, and non-polar substance paperclip. As a result, surface tension is broken and the paper clip sinks.