The Chemistry of Water
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Virginia Harris DuSable High School
4934 S. Wabash Ave.
Chicago, Illinois 60615
Grade level: Ninth
1. To discuss the phenomenological properties of water.
2. Discuss and demonstrate solubility of liquids.
3. Students will define and give examples of expansion.
4. Demonstrate surface tension individually and as a group.
5. Students will make a water molecule combining the class molecules together
(For each student.)
One large beaker, black pepper, one small needle, water, and a dish washing
One large styrofoam ball, two small styrofoam balls, two toothpicks.
Review properties of water showing the natural existence of water in three
states. Discuss and demonstrate the solubility of water using sand, sugar,
oil, vinegar and salad dressing. The students will readily recognize that
all substances do not dissolve in water and that there are other liquids
that are good solvents.
Students will observe a can of coke that has been left in the freezer over-
night. What happened? Why? Car radiators sometimes freeze in winter. Why?
In Activity 1, students will fill a large plastic container with water.
Sprinkle the surface of the water slightly with black pepper. Discuss
observations. Drop a dish washing detergent in the center of the dish.
Observe what happens. Class will discuss observations.
Place some water in a large plastic cup. The water can be at any level in
the cup. Let the water stand for two or three minutes. Place a small
needle on the surface of the water. Observe what happens? Why? Place a
small needle on the surface of the water using forceps. Discuss
observations. Was it easier to place the needle on the surface of the water
with your fingers or with the forceps? Class will discuss their
observations and give reasons as to what they think happened.
In Activity 2, students will construct a water molecule showing how the
hydrogen atoms are bonded to the oxygen atom using toothpicks. The class
will bond their molecule with another molecule (in a straight chain) to show
how water is formed. The water molecule looks very much like a Mickey Mouse
hat. It has a covalent bonding and is polar because of the 105 degree angle
between the hydrogen atoms.
The natural existence of water in three different forms is indeed a
phenomenon. Plants and animals cannot survive without it. We use it in
every aspect of our daily lives. Solubility, expansion and surface tension
are some of the properties that makes water unique.
We should not waste or pollute water because there are some countries who do
not have any water. We should always remember those without and create ways