How Strong Is The Solution?
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Ernestine C. Davis Horace Mann Elementary School
8050 S. Chappel Ave
Chicago IL 60617
The 2nd and 3rd Grade students will:
- Follow directions and procedures in the science laboratory.
- Make a mixture of food coloring and water and then determine which
solution is stronger, using bleach to remove the color.
- Use bleach to remove the color from and paint designs on construction
- Make sugar solutions and determine the sweetest of these by taste.
- Bleach (Hazards: eye, skin, respiratory irritant, and poisonous)
- Clear Plastic Cups
- Construction Paper
- Food Coloring
- Paper Towels
- Coffee Stirrers
- Baby Food Jars
The teacher will demonstrate making a mixture of food color and water. The
teacher will ask students questions such as: What happen to the water when
I add one drop of food color? What do you see when I add two drops? Does
the amount of water change? What happened to the strength of the solution?,
etc. During the discussion the teacher will bring in definitions of
solution and strength of solution.
A. Before starting this lab students must be reminded of precautions. You have
seen the action of bleach on colors. When you use bleach in the laundry,
you must be careful not to use it on colored clothes. Why? What could
happen if you did use it by accident? You will be able to answer this
question from the results of this experiment. The action of bleach can be
shown using the water solutions of different food coloring, as well as
various other colored substances. The teacher will monitor students for
safety and correct use of all materials.
Students Making Mystery Food Color and Water Solution The teacher will
demonstrate adding bleach to food coloring.
A. Divide students into groups of six. Assign each group one food color: red,
blue, green, yellow, orange, and purple. Record all of your answers in the
Results and Observations Section of your worksheet.
B. Each student in the group has a cup of water and add one to six drops of the
assigned food color. They will write their names on the label on the cup.
C. The student will write the number of drops used on an index card, keeping
the number of drops used a secret.
D. The group now arranges their six cups in order by depth of color (still not
having revealed number of drops of color used). Record this order.
E. Which cup in their series do they predict will need the most bleach?
Students test this by adding bleach and counting drops. Record drops/cup,
and compare the number of drops to the order in which they put the cups.
Finally they will reveal the number of mystery drops.
F. Each student will graph (bar graph) group results: The number drops of food
color (horizontal) vs number of drops bleach (vertical).
Each student will make a design by using a Q-tip to apply bleach to
different colors of construction paper.
The student will be able to tell how many drops of bleach are required
to clear solutions with different amounts of food color. They will
be able to define concentration and solution. They will be able to make
a bar graph.
The removal of color is dependent upon the strength of the color and the
amount of bleach used.
Kitchen Chemistry, Carson-Dellosa Publisher
Mr. Wizard's Supermarket Science, Book Lab