{"id":58,"date":"2016-11-25T12:57:00","date_gmt":"2016-11-25T12:57:00","guid":{"rendered":"http:\/\/magicscientist.com\/2016\/11\/measure-surface-tension-with-a-penny-science-experiment-for-home-or-classroom"},"modified":"2016-11-25T12:57:00","modified_gmt":"2016-11-25T12:57:00","slug":"measure-surface-tension-with-a-penny-science-experiment-for-home-or-classroom","status":"publish","type":"post","link":"https:\/\/puppetbuildingworld.com\/magicscientist\/?p=58","title":{"rendered":"Measure Surface Tension with a Penny Science Experiment For Home Or Classroom"},"content":{"rendered":"

Measure Surface Tension with a Penny<\/h1>\n

<\/p>\n

\n
<\/source><\/source>\"\"<\/div>
Learn about the secrets of soap in this surprising surface tension-testing activity!  <\/i><\/figcaption>
Credit: George Retseck<\/i><\/figcaption>
<\/i><\/figcaption>
<\/div>\n
<\/a><\/div>
JOIN US ON FACEBOOK <\/b><\/span><\/a><\/i><\/figcaption><\/figure>\n

\"https:\/\/www.youtube.com\/channel\/UCNUVS8n-3_Vwupc9I8PGhuw\"<\/a>  JOIN US ON YOUTUBE <\/span><\/a><\/strong><\/p>\n

Key concepts<\/strong><\/span>
Chemistry
Molecules
Surface tension<\/p>\n

Introduction<\/strong>
Have you ever noticed on a rainy day how water forms droplets on a window? Why does it do that instead of spreading out evenly over the whole surface? You might not guess it but this property of water is also related to washing dishes and doing the laundry. How? It all has to do with something called surface tension. Try this activity to learn more!<\/p>\n

Background<\/strong>
You have probably noticed that if you look at a surface outside on a rainy day or spill some water inside, the liquid tends to form droplets that stick up from a surface instead of spreading out into an even sheet. This occurs because water is made up of many tiny molecules that are all attracted to one another. Molecules in the middle of a drop of water are pulled evenly in all directions by all the nearby molecules. Those near the droplet\u2019s surface, however, are pulled mostly inward by the water molecules below them. This creates “surface tension.” The surface of the water droplet is held together by the attraction between molecules.
Now, think about washing dirty dishes or clothing. There will be lots of tiny little holes and cracks that water needs to get into to wash away dirt and grime, such as the spaces between the fibers of a shirt or between a plate and bits of dried food. In order for water to flow more easily into these small spaces, you need to decrease<\/em> its surface tension. You can do this by adding soap, which is a surfactant (a material that decreases the surface tension of a liquid). In this activity you will see how soap decreases the surface tension of water by putting water droplets on top of a penny.<\/p>\n

Materials<\/strong> <\/p>\n