### Summary

Students are challenged to design and build spinners that spins the longest. They build at least two simple spinners to conduct experiments with different mass distributions and shapes. Use this hands-on activity to demonstrate rotational inertia, rotational speed, angular momentum, and velocity.### Engineering Connection

Engineers understand the concepts associated with circular motion and angular momentum as they design equipment, systems and products with spinning components. Aerospace engineers design satellites to spin as they orbit around the Earth so that they do not tumble out of control. Automotive engineers design car parts to spin in specific ways so that they do not come apart at high speeds. Mechanical engineers design generators, washers, dryers, fans and other machines so that they are balanced as they spin. Even a forward pass in football is more effective and stable with the right spin.

###
Educational Standards
Each *TeachEngineering* lesson or activity is correlated to one or more K-12 science,
technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in *TeachEngineering* are collected, maintained and packaged by the *Achievement Standards Network (ASN)*,
a project of *D2L* (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; *e.g.*, by state; within source by type; *e.g.*, science or mathematics;
within type by subtype, then by grade, *etc*.

Each *TeachEngineering* lesson or activity is correlated to one or more K-12 science,
technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in *TeachEngineering* are collected, maintained and packaged by the *Achievement Standards Network (ASN)*,
a project of *D2L* (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; *e.g.*, by state; within source by type; *e.g.*, science or mathematics;
within type by subtype, then by grade, *etc*.

###### Next Generation Science Standards: Science

- Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success. (Grades 6 - 8) Details... View more aligned curriculum... Give feedback on this alignment...
- Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved. (Grades 6 - 8) Details... View more aligned curriculum... Give feedback on this alignment...

###### Common Core State Standards: Math

- Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities. (Grade 7) Details... View more aligned curriculum... Give feedback on this alignment...
- Solve linear equations in one variable. (Grade 8) Details... View more aligned curriculum... Give feedback on this alignment...
- Rearrange formulas to highlight a quantity of interest, using the same reasoning as in solving equations. (Grades 9 - 12) Details... View more aligned curriculum... Give feedback on this alignment...

###### International Technology and Engineering Educators Association: Technology

- Some technological problems are best solved through experimentation. (Grades 6 - 8) Details... View more aligned curriculum... Give feedback on this alignment...

###### Colorado: Math

- Solve real-world and mathematical problems involving the four operations with rational numbers. (Grade 7) Details... View more aligned curriculum... Give feedback on this alignment...
- Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters. (Grades 9 - 12) Details... View more aligned curriculum... Give feedback on this alignment...

###### Colorado: Science

- Use mathematical expressions to describe the movement of an object (Grade 8) Details... View more aligned curriculum... Give feedback on this alignment...
- Develop and design a scientific investigation to collect and analyze speed and acceleration data to determine the net forces acting on a moving object (Grade 8) Details... View more aligned curriculum... Give feedback on this alignment...

### Learning Objectives

After this activity, students should be able to:

- Explain how mass and radius relate to angular momentum.
- Describe the law of conservation of angular momentum
- Collect, analyze and interpret data on the rotational speed of an object and correlate the speed to variations in the geometry of the object
- Explain how engineers apply the concepts associated with circular motion and angular momentum to design equipment, systems, and products with spinning components

### Materials List

Each group needs:

- a flat round object, such as a jar lid, compact disk or paper plate
- 2 pencils (or, alternatively, thumbtacks or pushpins)
- tape
- 2 rubber bands
- cereal box-weight cardboard
- 6 pennies
- scissors
- markers
- The Spin on Things Worksheet, one per person

### Introduction/Motivation

Aerospace engineers design satellites to spin as they fly above the Earth so that they do not tumble out of control. Automotive engineers design car parts to spin in very certain ways so that they do not come apart. Mechanical engineers design generators and other machines so that they are balanced as they spin. Even children on playgrounds who play on swings and spinning merry-go-rounds for fun care a lot about how things spin!

With today's activity and worksheet, you will explore how things spin. What makes some things spin a long time, and other things fall over right away? What is the best shape for a spinner? How do spinners work? We will find the answers to these questions and more!

### Procedure

Before the Activity

- Gather materials and make copies of The Spin on Things Worksheet.
- Have students bring in from home some circular objects such as jar lids and old CDs, pennies, and cardboard cereal boxes or paper plates.

With the Students

- Discussion: Ask students if any of them has ever built a spinner. If necessary, explain what a spinner is. With what did they make the spinner? (Examples: A football, a penny, etc.) How do their spinners work? Explain that in this activity students will learn more about how spinners work as they design and build their own spinners.
- Draw three circles on cardboard by tracing around a circular object. Cut them out.
- Poke a pencil through the middle of one of the cardboard circles. Hold it firmly in place by winding rubber bands around the pencil above and below the cardboard.

- With a marker, draw a thick, dark line at any point on the cardboard spinner top. Have the students spin the spinner. Count the number of rotations the spinner makes within 10 seconds. Write this number down. (The line must be very dark to be able to read it while the shape is spinning.)
- Poke the pencil through another disk at a point away from its center. Describe the motion.
- Give your spinner a long handle and a short tip by pushing just a little of the pencil through the hole. How well does the spinner spin?
- Now push most of the pencil through the cardboard circle to make a long-tipped spinner with a short handle. Does the spin change?
- Now tape six pennies on to the outer rim of one spinner, and six pennies close to the center of another spinner (both spinners should have the pencil at the center of the circle).
- Repeat Step 4 with both of these spinners.

- Cut a square or triangle shape from cardboard. Poke a pencil through the center and give it a whirl. Which top stays spinning the longest? Repeat Step 4 with this spinner.
- Have student groups fill out the worksheet and check their answers with another student group.
- Review the worksheets with the entire class.

### Attachments

### Safety Issues

Sharp pencil points and thumbtacks present a hazard.

### Troubleshooting Tips

If the pencils are too unstable, thumbtacks or pushpins may serve as a better axis for the spinners to rotate about.

Sometimes the spinner is hard to keep balanced. It may take the students several tries before they can balance the spinner and count the line as it passes.

Keys to spinner design (Hauser, 1999):

- A disk shape evenly distributes the mass about the center. That is also why poking the pencil through the center works best.
- A long handle and a short tip. The top is more stable when it has a low center of gravity.
- Weight evenly distributed at the outer edge gives the top more spinning inertia.
- The harder you twist when you start the spinner, the longer the spin.

### Assessment

Pre-Activity Assessment

*Discussion Questions:* Ask the students and discus as a class:

- Has anyone has ever built a spinner? If necessary, explain what a spinner. With what did they make spinners? (Examples: A football, a penny, etc.) How do their spinners work? Explain that in this activity, students will learn more about how spinners work as they make and test their own spinner designs.

Activity Embedded Assessment

*Worksheet:* Have students use the activity worksheet to help them complete the activity. Review their answers to gauge their mastery of the subject.

*Pairs Check:* As student groups finish their worksheets, have them check their answers with another team, giving all groups time to finish the worksheet.

Post-Activity Assessment

*Class Presentation:* Have the groups present their best spinner designs to the rest of the class and discuss why they worked best, in terms of the rotation concepts.

### Activity Extensions

Have students devise their own spinning creations at home, using lids, plates, cardboard and other household materials. Have them report back to the class what designs worked best. Have them demonstrate using their homemade spinners.

Hold a contest to see which spinner can spin the longest. Ask the team with that spinner to explain why their spinner lasts the longest.

### References

Hauser, Jill Frankel. *Gizmos and Gadgets: Creating Science Contraptions that Work (and Knowing Why)*. Charlotte, VT: Williamson Publishing, 1999. (Activity adapted from Hauser.)

### Contributors

Ben Heavner; Sabre Duren; Malinda Schaefer Zarske; Denise W. Carlson### Copyright

© 2004 by Regents of the University of Colorado### Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder### Acknowledgements

The contents of this digital library curriculum were developed under grants from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation (GK-12 grant no 0338326). However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: May 12, 2016

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