TOOTSIE ROLL LAB

Objectives: Use real data to explore linear relationships.

Use graphing capabilities of TI-83 to visually analyze the data.

Supplies:

1. You will need 2 or 3 sizes of Tootsie Rolls, at least 1 of each size per group and then use class data. You could have each group test more than the 1 of each size candy if time permits. If you can’t find a third size of TR you could cut large ones into smaller pieces.

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2. One ‘test” tootsie roll.

3. 100 ml Graduated cylinders and water if you will measure the volume by water displacement.

This lab examines the linear relationship between mass and volume for a particular object. Once a relationship is established students will determine if a test Tootsie Roll comes from the same population as the sample. By graphing the data, students will see another meaningful application of ratios and slope.

Instructions:

1. Measure the mass and volume of the sample Tootsie Rolls.

2. Enter the data into the calculator and graph. Does the data appear linear? If not, is there any relationship?

3. Make a best fit line and graph. What is the slope of the line? What does slope represent in this problem?

4. Graph two more lines representing upper and lower bounds on the error due to measurement.

5. Measure the mass and volume of the test Tootsie Roll.

6. Plot one your graph.

7. Do you conclude the test data is from the same population? Clearly support your conclusion.

To the instructor:

1. Determine the max. error in your measurements before class. The error terms will depend on your equipment.

2. Each group must enter data into the calculator. If your students are not familiar with the technology you may have to provide additional instructions.

3. Do not pass out the test tootsie roll until the graph with error has been created.

4. Students may need help graphing error lines. Suggested method is to apply error terms to each data point. For example, if the volume is 7±0.5 and mass is 10.133±0.002 then an upper data point would be 10.135,6.5 and a lower data point would be 10.131,7.5.

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David Anderson 2002-08-01. Adapted from work provided in the course, Creating Labs To Connect. Math Tech institutes summer 2002