Will A Paper Clip Float On Water?

True or False: If carefully placed, a paper clip will float on top of water due to a molecular skin created by the interaction of air molecules and the surface layer of water molecules. 




While a paperclip can float on top of the water due to high surface tension, the answer to the statement is false because there is no skin on the surface of the water.

According to the USGS, “There is not really a ‘skin’ at the water/air meeting point—it is just water below and air above. Molecules on the water surface don’t have the same attraction to the air molecules above them as the other water molecules below them…water is attracted to water (cohesion). This inward net force causes the molecules on the surface to contract and to resist being stretched or broken. The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. It is surface tension which allows things to float on water that you would not think could, such as paper clips and bugs.” (Source: USGS)

Surface Tension

To better understand what makes this phenomenon possible, it is helpful to understand surface tension. In researching what allows a paper clip to float on the surface of water, there were several definitions of surface tension which together help paint a better picture of surface tension. Below are a few of the definitions found during our research.

Surface tension “property of a liquid surface displayed by its acting as if it were a stretched elastic membrane.” (Source: Encyclopedia Britannica)

“The surface tension of a fluid is the elastic tendency of the fluid surface which makes the fluid acquire the least surface area possible.” (Source: Natural Water Remediation)

Surface tension “is a contractive tendency of the surface of a liquid in contact with air, or another specific gas, that allows it to resist an external force.” (Source: ScienceDirect)


[1] Usgs.gov. 2022. Surface Tension And Water | U.S. Geological Survey. [online] Available at: <https://www.usgs.gov/special-topics/water-science-school/science/surface-tension-and-water> [Accessed 16 January 2022].

[2] Encyclopedia Britannica. 2022. Surface Tension | Definition, Examples, & Facts. [online] Available at: <https://www.britannica.com/science/surface-tension> [Accessed 18 January 2022].

[3] Speight, J., 2020. Natural Water Remediation. Kidlington, Oxford: Butterworth-Heinemann, an imprint of Elsevier.

[4] Camuffo, D., 2014. Microclimate For Cultural Heritage. 2nd ed.

[5] W. and Francis, C., 2022. Why Does A Metal Paper Clip Float On Water Despite Having An Acute Contact Angle?. [online] Physics Stack Exchange. Available at: <https://physics.stackexchange.com/questions/555199/why-does-a-metal-paper-clip-float-on-water-despite-having-an-acute-contact-angle> [Accessed 18 January 2022].


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