Jane Mole

Mrs. Mole, a former science teacher and current substitute teacher at Cherry Valley demonstrates the principles of adhesion, cohesion and surface tension.

 

 

 Mrs. Mole filled a cup all the way to the very top with plain tap water.

 She then proceeded to drop paper clips into the water, one-by-one, asking us to guess how many paper clips she could put into the cup before the water overflowed the top of the cup.
 

 

 Our Guesses:

FIVE!

TWELVE!

TWENTY!

FIFTY!

What?

ONE HUNDRED AND THREE!!

How can that be?

Through this experiment we explored water's desire to hold itself together, called cohesion. When you add objects slowly, one by one, surface tension forms a "skin" holding the water in the cup. Adding the clips slowly allows the water "skin" to stretch. We also discussed adhesion which is the force and result of attraction between dissimilar molecules (as in the water sticking to the glass)

 The final experiment showed what happened when we "jiggled" or moved the cup. We broke the surface tension and, of course, the water overflowed the cup.

 

 

Mrs. McCrumb's Class

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