Chemical Changes

Geraldine Smith Delano School
3937 W. Wilcox
Chicago IL 60624
(312) 534-6620

Objective:

The students in grades 3-8 will be able to explore some properties of Chemical
Changes.

Material Needed:

Medicine dropper Vinegar
Baking soda Green food color
Hydrogen peroxide Tooth pick
Clear plastic cup Bleach
Apron Safety goggle
Apple Knife

Strategy:
One way of describing the characteristics of a pure substance is by its
chemical properties. A chemical change produces a new substance with different
chemical properties. Chemical properties help you describe the way one
substance will chemically react with another substance. Color changes, solid
formation, bubble of gas formation, and color disappearance are indicators of
chemical changes. In this experiment you will look at some chemical changes.

Experiment 1
Cut an apple into two sections. Observe the exposed area immediately. After
ten minutes observe what happens to the inside color. The oxygen in the air
reacted chemically with the apple and caused a color change.

Experiment 2
Pour a quarter cup of vinegar into a clear plastic cup. Add a teaspoon of
baking soda to the vinegar and observer. The vinegar reacted chemically with
the baking soda and produced bubbles of carbon dioxide.

Experiment 3
Put a drop of green food color in a clear plastic cup. Add a half cup of water.
Mix with a toothpick. Place some bleach in another cup using the medicine
dropper. Add 30 drops of bleach to the water and green food color. Observe
what happens. The bleaching of the green color by the bleach is an indication
of a chemical change.

Experiment 4
Place a quarter cup of hydrogen peroxide in a clear plastic cup and add a slice
of apple. Observe the slice of apple and check for the formation of bubbles.
The decomposition of hydrogen peroxide to produce oxygen as one of the products
is an example of a chemical change.

Performance Assessment:
The student should receive 25% for each experiment done correctly.
Return to Chemistry Index