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Elementary Science Activities: Inquiry, Part Two


Chewing gum is forbidden in most schools, but under proper supervision it can be used to demonstrate the scientific method in an interesting way. The experiment assumes that students can use a balance to weigh accurately to a tenth of a gram. Each student gets one piece of gum. Do not use sugarless gum.

Teacher Notes for the Experiment

Students should make a simple table numbered 1- 10 minutes and record the weight after each minute. The procedure is simplified if all students are kept on task by having the teacher keep time and announcing when each minute has expired, when to weigh, and when to begin chewing gum again. This procedure ensures that the students will all be doing the same thing at the same time.

The teacher may choose to have students graph results with minutes on the X — horizontal — axis and the weight on the Y — vertical — axis. The graph line should begin to level out after a few minutes. The loss of weight is due to the loss of sugar, which also explains why the gum shrinks in size. The difference for different brands will not likely be significant.

Be sure that students always place the gum on its original wrapper and that it is weighed also. After the gum-chewing is done, have students dispose of gum one at a time by wrapping it and placing it in a trash can near the teacher who will monitor disposal.

The loss of weight will be about 50% of the weight of the gum. This also presents a good argument for why sugarless gum is better for teeth.

The experiment follows the steps in the scientific method and can be used as a model to introduce how proper science projects should be designed. Call attention to the “If…then” statement in the hypothesis, which is standard. The conclusion should answer the question presented in the hypothesis.

Teachers should be sure that students notice the “If…then” construction of the hypothesis. “If” introduces the independent — manipulated — variable and “then” introduces the dependent — responding — variable. A simple generic statement for the hypothesis is, “If I do A, then the result or outcome is B.

The conclusion does not have to support the hypothesis. Whether it agrees or not, something is learned. In other words, it is just as important to know that the hypothesis is correct as it is to know that it is not correct. In this experiment, however, the hypothesis should be supported.

Before beginning, the teacher should have selected three popular brands of chewing gum of nearly equal weights per stick. Average the weights of three different sticks for future reference and use a control.

Hypothesis:

If three different brands of chewing gum are chewed for a total of ten minutes each, then the amount of sugar lost will be the same for each brand.

Materials:

  1. 1 stick of chewing gum from 3 different choices
  2. triple beam balance
  3. watch, clock, or other timing device

Procedure:

  1. Unwrap the gum and save the foil wrapper.
  2. Place the wrapper on the balance to keep the gum clean.
  3. Before chewing the gum, place it on the balance and weigh it to the nearest tenth of a gram — be sure to weigh the wrapper with the gum.
  4. Record the weight on the table below.
  5. Chew the gum for exactly one minute, place it with wrapper on the balance and weigh it.
  6. Record the weight in a table after each minute.
  7. Repeat steps 5 and 6 until 10 one-minute trials are complete.
  8. After completing the table, make a graph as directed by the teacher.
  9. Compare results of all three of brands chewed to the average weight of unchewed gum, which were weighed prior to beginning the procedure.

Conclusion:

The amount of change for each type of gum will be essentially the same. The data should be averaged for each brand. Small differences of a few tenths should not be considered significant — in higher grades some discussion of how one decides if differences have importance is prudent, but this is a matter of statistical significance and not a recommended discussion until students can grasp the concept numbers being different but not significantly so. The discussion of significance is optional, but basically would involve what things — extraneous variables — might have resulted in small differences.

Optional Questions

  1. What was the independent variable? This will be the thing that is deliberately changed, i.e. the brand of gum.
  2. What was the dependent variable? This will be the thing that changed — or didn’t, i.e., the weight of the gum.
  3. What was the control? The average weight of the unchewed gum is the control.
  4. List at least three variables that might affect the results. This refers to extraneous variables — a term that the teacher can choose to omit — but the teacher should engage students in a discussion of “things” that explain why data varies from student to student. Possible extraneous variables include student techniques in weighing, different speeds of chewing, etc.

The experimental method can be introduced with easily understood and interesting procedures. Even simple methods can contain the essential parts of experimentation — the dependent and independent variables, the hypothesis and the conclusion, the procedure and extraneous variables, and the control. The above experiment is generally appropriate for fourth grade and higher.