Thursday, July 17, 2014

Water's Tensile Strength--Water Science

 Today we did an experiment...an oldie but a goodie...What makes it even more fun is the fact that this bunch of kids have never done these particular water experiments before.  I forget sometimes that even if something has been done in our homeschool before there are several children who may not have experienced it before.
This time we took a guess has to how many water drops we could get to stay on the top of a penny, (or nickel or quarter)  The guesses ranged from 8 to 10, which, with 4 kids making hypothesis surprised me.  I think they were influenced by each others guesses.
 
 If fact, the highest number of drops was 19.  We learned about tensile strength and the fact that water definitely has "strength" on the outside "skin" of the water.
 Once the water started to flow, it all flowed off the penny.
 31 drops were put onto a nickel.  (This surprised me!)
 We then tried a new to us experiment.
We filled a jar to the very top.  Next, drop pennies gently into the jar, trying not to disturb the water.
 Mark managed to drop 36 pennies into the jar.  In the process a beautiful dome of water rose above the rim of the jar.  The 37th penny sent the water flowing from the jar.
 And what does dish detergent do to the surface of the water.
Sprinkle a bowl of water liberally with pepper.
Dip a toothpick covered with dish detergent into the center of the pepper.
Watch the "magic" happen....or is it science??
video

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