This WordPress.com site all about kindergarten science.

Posts tagged ‘surface tension’

Feeling the Tension

      Surface tension is an interesting thing to play with.  This first experiment I did not think was going yo work.  I put a wet handkerchief over a glass full of water.  Put a rubber band around the handkerchief to hold it in place and turned the glass over.  I thought it was going to dump water everywhere. I was quite surprised.

Image

Image

     The surface tension of the water in the handkerchief held the water in the glass.  The next time I try this I want to try it with a dry handkerchief.  Will it still work?  How about if after turning over the glass and wet handkerchief I rub a little soap on the handkerchief.  That might be interesting.  Who knew a little piece of cloth could hold back water.

     The next surface tension experiment I did was to “tie” water together.  I poked three holes near the bottom of a plastic container.  Then filled the container with water.  There are three streams of water. 

Image

     If you put your hand in front of the water and pinch the streams you can make them connect into one stream.  This took a little practice. 

Image

       This would be a fun activity in a water table or at home in the bathtub.  Does it work with soapy water?

     The third experiment I tried has nothing to do with surface tension.  It is about balance.  I balanced different coins on a ruler.  The heavier coins could be balanced with the lighter ones if they are moved closer to the center.  You could present the challenge of how to balance 10 pennies and 5 quarters. (or what ever number of coins you wanted).  This could be done with other objects of varying weights, but I had coins on hand.

Image

Image