Objective: The student will use estimation, calculation of percentages and subjective-reasoning skills.
Resources: Teacher: One apple per student; one scale or balance with weights per group; napkins. Students: paper and pencil.
Teacher Preparation: Wash apples.

Procedure:
1. Have class discussion about percentage and what students consider to be the edible part of fruit.
2. Divide class into cooperative learning groups.
3. Hand out apples and napkins.
4. Have students estimate what part or percentage of apple is edible.
5. Instruct students to weigh apples (and napkin) and record result on paper.
6. Students eat their apples, saving all uneaten parts on their napkin.
7. Students should then weigh the napkin holding the uneaten part of the apple.
8. Students subtract weight of uneaten part from whole weight to find weight of edible part.
9. Students divide edible weight by whole weight to find percentage.
10. Have one person from each group record the data from each person.
11. One person from each group shares with the class the data and examples of uneated parts of apples, comparing the estimations with the actual results.

Variations/Options: Teacher can combine this exercise with a discussion of the subjective nature of a definition and how that influences a scientific procedure.