Judy Lehmberg (FLC I) - Lee College

2. In order for the liquid water to evaporate and become steam, heat must be added. In a pan of boiling water,
what bond is being broken by the heat of the stove?
Hydrogen bonds
3. So, if heat is required to evaporate water, then what is released when water condenses?
energy
4. On a calm, but rainy day, the temperature rises slightly when it starts to rain. Explain.
As it begins to rain many water molecules are changing from the vapor state to a liquid. As they change from
one state to the next they are forming hydrogen bonds. When hydrogen bonds form between water molecules
energy is released in the form of heat.
WATER ADHESION Adhesion occurs when two or more different substances are stuck together as if by glue.
Water has some interesting adhesion properties.
GO GET:
1. A small container of water.
2. An eyedropper.
3. Four microscope slides.
NOW:
1. Put several drops of water on one slide, then place the other slide directly on top of the wet slide.2. Try to pull
apart the glass slides without sliding them past each other.
3. Repeat this experiment with the two dry slides.
QUESTIONS:
1. How strong is the force of attraction between the two dry slides?
Not very strong
2. How strong is the force of attraction between the two wet slides?
It is fairly strong.
3. What is the name of the force that holds the two slides together?
Adhesion, it is due to the attraction between water molecules.
4. A freeze-dried anchovy is fairly easy to break between your fingers. Yet, when the fish is allowed to sit in
water for a while, it will only bend with the same effort. Explain.
A freeze-dried anchovy has had all of its water removed and is therefore easier to break. One of water’s many
functions is to help hold a living organism together due to the attraction of water molecules to other negatively
and positively charged substances.
5. Based on your answer to #4, what is one important role of water in living organisms?
See second sentence in answer to #4.
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