okay class, today we will cover cohesion. it is the action or property of water molecules sticking together. They are mutually attractive due to shape and structure of molecules. create microscopic structures like water drops.
we will be doing an experiment using a penny to explore the qualities of cohesion.
Carefully, drop individual drops of water onto the flat surface of the penny.Keep track of the water drops as you add them, one at a time, until water runs over the edge of the penny. You’ll probably be surprised by the number of drops you get on there!
Water’s cohesion and surface tension are special because of hydrogen bonds. Hydrogen bonds are formed by the hydrogen atoms of one molecule being attracted to the oxygen atoms of another molecule
The cohesion and surface tension of water becomes apparent when the drops of water you add to the penny reach the penny’s edge. Once the water has reached the edge, you begin to see a bubble or dome of water forming on top of the penny. The bubble shape is a result of the water molecules clinging to one another in an optimal shape