Starches and Fats

Alean Stancil St. Gelasius Elementary School
6358 S. Blackstone Avenue
Chicago, Illinois 60637


The student will:
1. observe the presence of starches and fats in different foods.
2. distinguish between a food that contains starch and a food
that contains fats.
3. define the terms starches and fats.
4. classify the foods as starches or fats.

Materials Needed:

For a class demonstration
1. cookie sheet
2. eye dropper
3. Tincture of Iodine
4. typing paper
5. brown paper bag
6. bread
7. crackers
8. sugar
9. cooking oil
10. peanut butter
11. food models


1. To test for the presence of starch, put samples of bread, crackers and
sugar on a cookie sheet.
2. Place a drop of iodine on each of the samples.
3. Observe the samples and tell what happens.
4. The existence of fats are tested by placing a sample of cooking oil,
peanut butter and bread on a brown paper bag.
5. Note the change in each sample, the brown paper bag will
become saturated with fats.


Starches and fats are observed in samples of different foods. The bread
and crackers will turn a dark blue purple illustrating the presence of starch.
In contrast, the sugar sample turned brown indicating the absence of starch.
Additionally, fats are tested by the saturation of the brown paper bag by
cooking oil and peanut butter. The bread sample shows that fats are not

Caution: Tincture of Iodine drops should be administered by the teacher.

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