Class 3

      In Biology Class we learned about the properties of water and the way it reacts with other objects. We reviewed the properties of water, such as ability to moderate temperature, expansion upon freezing, versatility as a solvent and cohesive and adhesive behavior. For example, a water strider is able to walk or stride on water because of the hydrogen bonds and the surface tension that is created. Then we did a lab consisting of pennies, water and dishwater soap. I slowly count how many water drops (the dependent variable) I could put on the penny without it breaking.  Because of water's cohesive properties, the water is able to create a "bubble" affectThe class does it twice, but the third time we put a drop of dishwater soap in the water. The water spilled immediately after applying the soap. This experiment correlates with lab 1: milk and food coloring. The water in the milk reacted to the dishwater soap in lab 1. The lab shows that water molecules are attracted to other water molecules because of the charges of the oxygen(-) and hydrogen(+) charges that attract each other. The cohesion creates a surface tension in the water. Some substances can lower or change the surface tension (in this case the dishwater soap) of the water which makes it react and move.