Beacon Lesson Plan Library

GUM: More, Less, or the Same?

Lois Walsh
Bay District Schools


A laboratory activity confirming the law of conservation of matter by weighing chewing gum before and after it is chewed. ‘ Will it weigh more, less or the same? What happens to the matter?'


Solves real-world and mathematical problems involving estimates of measurements including length, time, weight/mass, temperature, money, perimeter, area, volume, and estimates the effects of measurement errors on calculations.

The student understands that there is conservation of mass and energy when matter is transformed.


-A piece of chewing gum for each student (bubble gum or any sweet gum works best)
-Metric Balance


1. Read procedure.
2. Gather materials.
3. Review health and safety.
4. Monitor student activity and lab reports.


Students should not handle their gum! It can be weighed before and after in its wrapper. The gum can also be transferred from the wrapper to the mouth with the wrapper and not be touched by the fingers. This is a science experiment; 1) health concerns: no germs should be spread 2) science concern: some of the gum’s weight could be lost to the fingers.

Teacher Prep:
The law of conservation of mass can be confirmed in this lab activity. Challenge students to make a hypothesis of the weight of the gum from chewing it : more, less, or the same. When it is less, where did it go? The weight is not lost but the sugar is dissolved and digested. (Students may think their gum will gain weight from the salvia.) The percentage of sugar present can be calculated.

1. Remember to not handle (touch your gum) in this experiment.
2. Use the gum wrapper to weigh the gum and transfer it.
3. Record a hypothesis.
4. Weigh the gum and wrapper and record the measurement.
5. Chew the gum for 3 to 10 minutes, until the gum loses its flavor.
6. Reweigh the gum and wrapper and record the measurement..
7. Dispose of the gum in the wrapper properly.
8. Clean up and return materials.
9. Complete Lab Report:
Data analysis: How much was lost or gained? Calculate the percentage. (Math: the difference in weight divided by the starting weight then multiplied by 100 = %) Conclusion: In an oral discusssion lead students to an explanation of where all of the gum’s weight is.


Students will complete a lab report with:
-Data measurements
-Data analysis
-Experimental procedure summary

If done correctly the gum will lose weight, the sugar is digested, and the % of sugar will range from 15 to 50 % depending on brands. Student will be able to relate the law of conservation of matter.

If not done correctly students can partner up and correct their lab report and then review the concepts as a class. This can be used as a formative assessment.


-This could be used to introduce or create a discussion of the law of conservation of mass and how matter behaves or it could be used as an exercise in the application of the law of conservation of mass. It also could be used as an assessment for the understanding of the law of conservation of matter(see below).
-Sugarless gum can be used for a second experiment or one student in a lab team could have the sugarless gum and the results compared witheach other. It could be used after this lab as a summative assessment.
-See Beacon Lesson available at this site: ‘What Happened to The Popcorn?’ for another law of conservation of matter lab activity.
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