Tuesday
September 11th
Water will form hydrogen bonds with other substances such as
glass, soil and plant tissues. The term for this type of attraction is known as
Adhesion
A combination of this and Cohesion can cause water to ‘defy
gravity’ by moving UP narrow tubes (such as the roots of trees) in a process
known as Capillary Action
After these daily questions we moved into our next set of activities on Adhesion and Capillary Action. The capillary action we saw (see pictures and video Below) was first caused by the adhesion of water to the glass. THEN - as the water moved into the tube Cohesion caused it to continue to rise. Remember, the water is still attracted to other water molecules so they "tow" each other up the tube.
The next activity was to see adhesion. I had you add drops of water onto a penny to see how it adhered. THEN I added soap to the penny. You noticed that when soap was added, you were not able to get as much water on there. Why?!?! The soap breaks apart the hydrogen bonds which causes a decrease in surface tension and adhesion. (more to come about this tomorrow)
After those - we continued with notes through the density of water. Tomorrow is our open notes quiz!! Be prepared!!!!!
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