Yo-Yo Motion

To develop students' understanding of change of speed and the effect of gravity through observations and explorations with a homemade yo-yo.

This lesson uses a common toy to help students explore concepts of motion. Benchmarks for Science Literacy suggests that the science curriculum focus on experiences and ideas accessible to children. In this way, students are provided with a background of experiences, which can be drawn on for more complex understanding of physical concepts. (Benchmarks for Science Literacy, p. 88.)

These yo-yo activities help students overcome a couple obstacles to their understanding of motion and forces. One obstacle is the perception that sustained motion requires sustained force. Another obstacle is that limitations in describing motion may keep students from learning about the effect of forces. Students of all ages tend to think in terms of motion or no motion. So the first task may be to help students divide the category of motion into steady motion, speeding up, and slowing down. The motion associated with the yo-yo is more easily observed than with a falling object. Children will be able to observe concepts about force, acceleration, and friction, including “it takes a force to change an object’s motion” (obstacle 1) and “falling objects should be described as falling faster and faster, rather than just falling down” (obstacle 2). Students will be guided to work out for themselves some of the general relationships between force and change of motion as they experiment and observe yo-yo motion. (Benchmarks for Science Literacy, p. 87.)

Ideas in this lesson are also related to concepts found in the following benchmarks:

• The Nature of Science: Scientific Inquiry (3-5) #1, 3

Materials:

• Yo-Yo Motion student E-Sheet
• Yo-Yo Motion student sheet
• Make a Yo-Yo student sheet
• Two 8 oz, plastic yogurt containers with lids for each student. Poke holes in the center of each cup’s bottom and the center of each lid with a large nail.
• One 8 1/2 inch piece of 3/16 inch diameter dowel for each student
• One 4-foot length of cotton cord for each student
• Masking tape
• A variety of store-bought yo-yos (optional)

We suggest that you read the Science NetLinks tool, Yo-Yos are Hoppin' to familiarize yourself with the content.

Begin this lesson by having students use their Yo-Yo Motion student E-Sheet to go to Yo-Yos are Hoppin’. Students should first read about the yo-yo contest and then click on "Watch a video of the competition" to see some of the tricks performed by yo-yoers. After they have looked at this resource, they should answer these exploratory questions found on their E-Sheet:

• Describe the yo-yo motions you see.
• What do you see contestants doing to make the yo-yos move?

Students should continue to use their E-Sheet to go to A New Spin on Things and study the pictures of yo-yos on the page. Once they're done observing the yo-yos, they should answer these questions:

• What is the same about all the yo-yos in the picture?
• How do you think the shape of a yo-yo helps it move?

Then students should go to Try This! to read about how to use a yo-yo. Ask students questions like these:

• Why do you think the length of string matters when yo-yoing?
• Navigate to any of the tricks. Which one looks the trickiest?

Invite students to bring yo-yos from home, or use ones you provide, to demonstrate their prior knowledge of how yo-yos move.

In this part of the lesson, students will further explore how yo-yos move by making and using one of their own. First, use student demonstrations and references to the video clip to direct observations with these discussion questions:

• What causes the yo-yo to move?
• What direction does the yo-yo move when it is dropped?
• What happens when the yo-yo is thrown in a different direction?
• When does the yo-yo seem to travel the fastest?
• When does the yo-yo slow down?
• What might make the yo-yo move slower?
• Why does the yo-yo travel back up the string?
• Does it travel up as fast as it travels down?

Explain that they will get a chance to explore these questions further by making and using their own yo-yo model. Hand out the Make a Yo-Yo student sheet and help guide them through the construction steps.

Make a Yo-Yo Instructions

1. Write a description about how to get the right length of string for your yo-yo based on tip number 1 from the Yo-Yos are Hoppin' site.
2. Poke the dowel through the hole in the bottom of one cup and through the hole in the lid. Snap the lid onto the cup.
3. Tie one end of the piece of cotton cord to the dowel close to the cup. Secure the string with a small piece of masking tape.
4. Attach the second yogurt cup and lid on the second end of the dowel, leaving a narrow space between the two cups.
5. Cut the string based on your description about how to get the right length for your yo-yo.
6. Tie a loop on the loose end.
7. Wind your yo-yos.

Once students have made their yo-yos, use the Yo-Yo Motion student sheet to take students through a guided discovery.

Allow time for students to share their observations from the "Drop and Watch" portion of the Yo-Yo Motion student sheet. Reinforce vocabulary words like force, gravity, and speed as they arise. Add explanations to clarify student understanding as it relates to their experiences and observations. Revisit initial discussion questions to apply to their hands-on experience.

Put on a yo-yo show. Have students share tricks recorded on their Yo-Yo Motion student sheets.

With partners, ask students to describe the changing motions of a yo-yo using the vocabulary words: force, speed, gravity, and friction. Allow partners to help each other clarify explanations as they practice. Record on a class chart which students are able to successfully use the vocabulary in their explanation.

Have each student design a poster including diagrams to illustrate the motion of the yo-yo as it falls and moves back up the string. Ask them to identify where the yo-yo moves fastest and slowest with labels and arrows. Ask students to use the vocabulary words in their descriptions.

Have students use nylon string and compare the motion with cotton string. Guide them to see that nylon string creates less friction and so affects the motion of the yo-yo.

Students can tie yo-yo string as a loose loop around the dowel, rather than a tight knot. Have students observe how long the yo-yo spins at the end of the string (sleeps). This process can be tried with both cotton and nylon string. Again, this is a good demonstration of friction.

Have a yo-yo design contest. Allow students to experiment with different sized containers, kinds of string, added weight (clay), or other variables they choose. Have each contestant change only one variable to help demonstrate science inquiry methods.

Students can learn more about modern yo-yo design by going to these websites: How Yo-Yos Work, from How Stuff Works.

Created :08/17/2006