Capillary Attraction - Naming a Phenomenon 
by Joshua Epstein('20) 

A lot like many of the wonders of the physical world, there are a lot of common-sense actions that we know work, however, lack a name for them. One term I believe should be more widely known is capillary attraction. That is, “a manifestation of surface tension by which the portion of the surface of a liquid coming in contact with a solid is elevated or depressed, depending on the adhesive or cohesive properties of the liquid”. We see capillary action, another name for it, very apparent in many commonplace activities. When you pour water into a glass, a concave meniscus forms because the water molecules are more attracted to the glass than themselves. That is why we see the water almost clinging to the sides of the cup instead of recessing into other H2O molecules and forming a simple flat surface at the top of the water. This specific occurrence is because glass, which is made up of very polar molecules, is commonly formed with a silicon oxide crystal lattice structure which is more attractive than H2O molecules. The tube on the left is the thinnest, so we see more capillary rise because there is more adhesion to the tube and pressure, which enables the H2O molecules to reach higher parts of the glass. And let’s say you spill some of that water on your table. When you go to clean it up with a paper towel, you will notice that even though only part of the paper towel will be touching the water on the table, it will slowly spread to the rest of the towel because of capillary action. Another common form of capillary attraction in your daily life could be seeing people water plants and trees, and if you are wondering how the water can travel from the roots to the highest part of some trees, the answer is by being helped by capillary action. Additionally, if you see a candle, capillary attraction allows the melted wax to rise up the wick to keep the flame alive. These are all good examples of how capillary action works in the world around you. However, if you are looking for examples of how it works inside of you, look no further than yourself on a sad night: capillary action helps your tears travel through your tear ducts! Below are two more common applications of capillary action. Capillary action has been studied for hundreds of years, dating back to Leonardo da Vinci, but some of the most substantive information we have on the phenomenon has been obtained in the last two centuries. For further information on capillarity, I recommend starting out with the Young-Laplace equation and the Kelvin equation.

References
Capillarity. (n.d.). Retrieved March 28, 2018, from http://www.dictionary.com/browse/capillary--attractio n Capillary action. (2018, March 16). Retrieved March 28, 2018, from https://en.wikipedia.org/wiki/Capillary_action Capillary action and why we see a meniscus.
(n.d.). Retrieved March 28, 2018, from https://www.khanacademy.org/science/biology/water-acids-and-bases/cohesion-and-adhesion/v/capillary-action-and-why-we-see-a-meniscus The Kelvin equation.
(n.d.). Retrieved March 28, 2018, from https://www.sciencedirect.com/science/article/pii/S0021979707014403 L. (2017, August 28). Capillary Action. Retrieved March 28, 2018, from https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Physical_Properties_of_Matter/States_of_Matter/Properties_of_Liquids/Capillary_Action Smith, P.
(n.d.). Capillary Action. Retrieved March 28, 2018, from https://astarmathsandphysics.com/a-level-physics-notes/fluid-dynamics/2746-capillary-action.html What are some of the applications of capillary action?
​(n.d.). Retrieved March 28, 2018, from https://www.quora.com/What-are-some-of-the-applications-of-capillary-action