Materials Included In Kit

Additional Materials Required

Prelab Preparation

Photocopy enough of the Fidget Spinner Design Template sheets for each student.

Safety Precautions

The tip of the wooden skewer is very sharp. Blunt the tip with sandpaper. Wear safety glasses. Remind students to wash their hands thoroughly with soap and water before leaving the laboratory.

Disposal

All items may be disposed of in the regular trash or kept for future use.

Lab Hints

• Enough materials are provided in this kit for 30 students working individually. Students work with a partner for Part A.
• Both parts of this laboratory activity can reasonably be completed in two 50-minute class periods. Part A can be completed on Day 1. Part B can be started on Day 1 and completed on Day 2. The pre-laboratory assignment may be completed before class.
• In the Design Challenge, cardboard sheets are priced per half-sheet. Fifteen cardboard sheets are supplied with the included materials. Students can cut the sheets in half and share with a classmate, or the sheets can be cut in half prior to performing the lab.
• To prevent flying washers, ensure that students allow any glue used in construction be given enough time to dry prior to spinning.

Teacher Tips

• Consider having students work in pairs for Part B. Each may make a prototype spinner, and then they must agree on which one to present to the toy company.

Answers to Prelab Questions

1. Read the Introductory Activity procedure.
   1. You are instructed to enlarge the hole in the cardstock to be slightly larger than the diameter of the skewer. Why might this be necessary?

      The hole in the strip is made to be slightly larger than the diameter of the skewer to reduce the force of friction between the cardstock and skewer while the spinner is in motion.

   2. Make a prediction as to which arrangement of paper clips will result in the longest spin.

      Student answers will vary. One possible prediction is as follows: The addition of more paperclips to each end of the cardstock strip will result in longer spin times.

Sample Data

Answers to Questions

1. Consider the results of the Introductory Activity.
   1. Describe your observations as more weight was added to the spinner.

      As weight is added to the spinner, the paper should spin more smoothly and for a longer time. However, as excess paperclips are added, the paper may not be able to support the excess weight. This may lead to the paper not spinning for as long.

   2. What effect did the placement of paperclips appear to have on the motion or spin time of the spinner? Give a possible explanation.

      Students should note that placement toward each end of the paper increases spin time.

2. How much money was spent during the design process? Estimate how much of that cost was attributed to waste.

   See Sample Data Table 1.

3. What is the final cost of the toy fidget spinner?

   See Sample Data Table 2.

4. Write a letter to FlinnToy summarizing your design initiative. Give the total cost for the manufactured toy. What is the longest and the average spin time of your toy? Why should the company pick your design?

   Dear FlinnToy,
   
   I have completed the design for a fidget spinner toy that spins for an average of 5.84 seconds. The final cost for each manufactured toy is $4.75. The toy’s longest spin time during testing was 7.22 seconds. The design includes the use of cardboard as the main body and two circular finger grips. Three large metal washer were used to add weight to the arms. In addition, one small metal washer was placed between the body and each finger grip. This was done in order to reduce friction between the body and finger grip while in motion, increasing the spin duration of the toy. This overall design minimizes friction and increases spin time while providing a strong and durable body for the toy.

Teacher Handouts

12375_Teacher1.pdf

Introduction

Explore the physics of fidget spinners while designing one of your own!

Concepts

• Friction
• Moment of inertia

Background

Fidget spinners are largely dependent upon two physics concepts—friction and moment of inertia. Friction is created when any two surfaces are in contact with each other. The factors that influence friction include the surface finish (or smoothness), the cohesive and adhesive ability of molecules, and the force holding the surfaces together. Surface finish is a major contributor to the frictional force. All surfaces, no matter how smooth, have irregularities. Commercial fidget spinners use a ball bearing at the center to minimize any frictional force that would otherwise slow down the spin of the toy.

As you may have noticed, many toy fidget spinners have ball bearings located on each of the arms in addition to the center. These are used to add mass to each arm. All mass has the property of resisting a change in motion, or inertia. An object in motion tends to stay in motion, and an object at rest tends to stay at rest. For rotational motion (spinning motion), the motion “resistance” is a property based on the mass and the spatial distribution of the mass around a point of rotation (or axis of rotation). This specialized case of inertia is called moment of inertia. The distribution of the mass affects the moment of inertia in such a way that the further the bulk of the mass is distributed from the point of rotation, the larger the moment of inertia will be, and therefore, the harder it will be to change the object’s motion. The mass added to the arms of the toy spinner reinforce this concept. Once the spinner has been put into motion, the mass on the arms makes it harder for the toy to change motion. In other words, the mass helps keep the arms spinning in the original direction. If, instead, the mass were moved closer to the center of the spinner, the toy would likely not spin as long.

Experiment Overview

The purpose of the Introductory Activity is to demonstrate the concept of moment of inertia by building a simple model. Next in the Design Challenge, you will design a fidget spinner using everyday materials. Who can design the longest spinning toy?

Materials

Prelab Questions

1. Read the Introductory Activity procedure.
   1. You are instructed to enlarge the hole in the cardstock to be slightly larger than the diameter of the skewer. Why might this be necessary?
   2. Make a prediction as to which arrangement of paper clips will result in the longest spin.

Safety Precautions

The tip of the wooden skewer is very sharp. Blunt the tip with sandpaper. Wear safety glasses. Wash hands thoroughly with soap and water before leaving the laboratory. Please follow all laboratory safety guidelines.

Procedure

Part A. Introductory Activity

1. Using scissors, cut out one 12 cm x 4 cm strip of cardstock.
2. Find the center of the strip using a ruler and mark it with a pencil.
3. Use the end of a paperclip to poke a hole through the marked spot.
4. Enlarge the hole by threading a bamboo skewer through, sharp end first. The hole should be slightly larger than the skewer.
5. Holding the end of the skewer in one hand, use your other hand to flick the strip of paper so it spins around the skewer. Repeat a few times until it moves consistently.
6. Next, spin the strip of paper while your partner records the spin time using a timer. Start the timer as soon as the strip is flicked, and stop when the paper comes to a complete stop. Repeat two times, and record the spin durations in the following data table.
7. Attach two paperclips to the strip of paper on each side of the bamboo skewer. Place the paperclips so they are as close to the skewer as possible without touching.
8. Spin and record the spin duration in the data table.
9. Slide the paperclips to each end of the strip. Spin and record the spin duration in the data table for three trials.
10. Use the remaining space in the data table to experiment with placement and number of paperclips for various trials. Record the duration of each spin, average spin times and any observations.
    {12375_Procedure_Table_1}

1. Record the materials used in the design process in Data Table 1 on the Fidget Spinner Design Worksheet. The cost of materials are listed below. Any material taken from the supply area should be accounted for. Do not account for any tape or glue used in direct material costs.
   {12375_Procedure_Table_2}
2. You must purchase each item as a whole. For instance, you cannot pay for only half of a sheet of paper—anything that is unused will count toward waste cost.
3. Record the required materials and costs for the final manufactured product in Data Table 2.
4. You will be given a designated amount of time to design and build the toy fidget spinner. Testing and making modifications must be made during that time period.
5. When time is up, test your design with a partner. Record your results in Data Table 3.

Basic Fidget Spinner Design

1. Cut out the design of your choice from the Fidget Spinner Design Template.
2. Choose a fidget spinner body from the provided materials. Trace the design onto the chosen materials, and cut it out using scissors.
3. Use a paperclip to poke a hole in the center of the spinner.
4. Widen the hole using the sharp end of a bamboo skewer. The hole should be slightly larger than the diameter of the skewer.
5. Using scissors, carefully score and break a 1.5-cm piece of bamboo skewer to use as the spinner bearing.
6. Use sandpaper to smooth the cut ends of the bamboo skewer.
7. Insert the piece of skewer through the hole in your spinner.
8. Hold the skewer between your thumb and index finger so the spinner is vertical. Use your other hand to flick the spinner.
9. Weights may be affixed to the arms of the spinner using tape or glue.
10. Two circular pieces of cardboard or foam can be placed on each side of the spinner body to prevent the body from moving while in motion; these can also be considered “finger grips” (see Figure 1).
    {12375_Procedure_Figure_1}

Student Worksheet PDF

12375_Student1.pdf