Observing Water Properties

Observing Water Properties

On Friday, April 10, we completed an in class lab to observe and understand the properties of water. To do so, each member of the
class received a penny, an eyedropper and a small cup of water. We than used an eyedropper to place one drop of water upon the surface of the penny. We continued this process until the penny could no longer hold any more water and therefore, the dome of water atop each penny collapsed.

Just previous to this experiment I decided upon and recorded my prediction of the amount of droplets the penny could hold- 7. I found the number logical at the time (as long as the drops were somewhat large) for I knew the amazing amount of strength and balance water possessed due to the force of cohesion, yet I was no where near close.

The penny turned out to hold an amazing 18 drops before the water collapsed, 11 more than I had previously predicted.

The outcome of this experiment was due to the force of surface tension. This same force is responsible for capillary action and is also why some small insects can walk on water. Surface tension occurs because cohesion (water particles sticking together) and adhesion(water molecules sticking to other substances). Together, these two forces cause the surface of such droplets to be incredibly and almost unbelievably strong.


Pictures: http://www.sci.sdsu.edu/classes/biology/bio100/truesdale/Lectures%2005/lec2/Image10.gif

http://farm4.static.flickr.com/3023/2917903711_9c1596854c.jpg?v=0