This lab examines the linear relationship between mass and volume for a particular object. By storing the mass and volumes into lists on the TI-83 students will use the linear regression capabilities of the calculator to see the line of best fit. By graphing the data, students will see another meaningful application of ratios and slope. Analyzing the data students will consider range, linear regression, and calculated single values (m/v=d) versus average values derived from the slope of the line of many points. Some basic error analysis will also be discussed.

• 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.

You probably won’t be able to find the American Flag TR. You could just take regular tootsie rolls and change the story, or unwrap them. You could also rewrap regular tootsie rolls in colored Saran wrap or Aluminum foil. Again, change the story.

Also needed:

• 100 ml Graduated cylinders and water if you will measure the volume by water displacement. You probably could use Pr²h if you can smash the TR into a more regular shape. Then, you will need rulers.

• 2 or more electronic or triple beam balances (borrow them from the science dept)

When doing this lab, I’d prefer not to tell the kids anything else; let them figure out what to do and what the significance of the ratio is...some of the kids will have learned about density, previously. Of course, you could have a class brainstorming session to determine what should be done and what exact procedures to use. You could talk about density being m/v before beginning the activity, or not. Add questions and analysis based on your level of student and the class you are teaching and the sophistication of data analysis you want them to do.

If you provide “product samples”, Tootsie Roll makes Dots, Sugar Daddies and Sugar Babies, Charms Blow Pops, Junior Mints and other stuff. Check out their website. www.tootsie.com

Variation:

Use marshmallows, mini and normal size or compare different brands of marshmallows.