|
juliefranzak
|
|
Discrepant Event Space Science
Julie Franzak ELED 305-42 5/31/2007 Science Area: Space Science Concept: Angular Momentum Moment of Inertia The Tin Can Race Paradox #5 Materials: Variety of round tin cans (soup, vegetables, fruit cocktail, tomato juice, dog food) Stop Watch (optional) Inclined plane ~1 meter long (wooden board propped up at one end by a stack of books) Stack of books Safety Considerations: Be sure that opened cans are free of sharp edges. Discrepancy: Many students will believe that larger cans will roll down the inclined plane at a faster rate than the smaller cans. Similarly,
the students will probably predict that a larger can containing loose mass will roll faster than a small can containing solid
mass just based on their sizes. Procedures: 1. Set up the board to form the inclined plane. 2. Divide students into group (3 students/group). S1: Releases the cans (at top of inclined plane) S2: Catches the cans (at the bottom of inclined plane) S3: Recorder/Observer 3. Let the each group choose a can they believe will roll the fastest (win the race). -take the average of three trials 4. Have two groups race each other at a time. *winner of race will participate in the next race against another group Declare a winner! Questions: 1. Which can is the overall winner? 2. What does the winning can contain? -What is the consistency of its contents? 3. How did the smaller cans compare to the larger cans? 4. How did the tomato soup can compare to the chunky soup can? 5. Were the heavier cans always victorious over the lighter cans? 6. What are the variables that determine the speed that the cans will roll at? 7. What are the manipulated and responding variables? 8. How can the other variables be controlled? Explanation: Some of the variables involved in the tin can race include but are not limited to the rolling speed of the cans (responding),
the can size, contents, weight, and the degree of incline of the plane; any of these latter variables can be manipulated.
For instance, racing cans containing the same contents but are different sizes (manipulation of the size of the can). The
consistency of the can can also be manipulated by taking cans of the same size, but different contents; in this case, the
can containing solid contents will win the race due to the moment of inertia seeing as it
has the least to overcome. Those cans that contain mass in loose chunks will, on the whole, be the slowest; in these cans,
there is a tendency for the mass to lay in the periphery of the can causing them to have the highest moment of inertia. In
order to compare rolling speed, hollow and solid cans should be used. Source: Liem, Tik L. Invitations to Science Inquiry: Supplemental 1st and 2nd Edition. Chino Hills,
CA: Science Inquiry Enterprises, 1991. 141.
|
|
Enter supporting content here |