This is the teacher guide for this lesson. A student-focused guide to assist learners as they perform the activity is available.
Teacher Guide
Losing Your Shirt
Experimenting with constraints
Is it possible to turn a t-shirt inside out while your hands are tied together?
This resource was originally published in PhysicsQuest 2014: Quantum.
Is it possible to turn a t-shirt inside out while your hands are tied together?
- Chopsticks
- Plastic zip tie
- Playdough
- Small bag
- Adhesive tape
- Scissors
- Pen or marker
Students start by discussing a problem. The experiment will guide students through one possible solution to the problem and then they will discuss the conclusions they can draw from their experiment.
- Total time45 - 60 minutes
- Education levelGrades 5 - 9
- Content AreaQuantum
- Educational topicConstraints, problem solving
You may be asking yourself, “why is this physics kit talking to me about folding laundry and what does an inside out t-shirt teach anyone about the physical world?” Shapes such as knots, donuts, and even t-shirts are used in many branches of science. From protein folding to the very fabric of our universe, it is important to understand how shapes can move and twist. What’s really neat is that learning about how something like a t-shirt, with its arm and neck holes, can move and turn inside out, can then give clues about how other things with the same number of holes and sides can flip around.
There is an entire branch of mathematics, called topology, that studies how knots tie and untie. The same ideas they use to describe knots and surfaces can be used to describe electric fields and vortices in water. The goal of this activity is to get the students thinking about how the shapes around them may move, what properties they have, and how they are similar and how they are different.
It's an intro to spatial reasoning using chopsticks and fashion. Normally to take off a shirt you would just pull it over your head. This brings the bottom of the shirt up and over the neck and arms and turns the shirt inside out. If you want to turn it right side in, you would probably reverse the process and bring the neck and arms through the bottom of the shirt. But that’s not the only way to turn a shirt inside out. It's just the way that stretches out the neck and sleeves the least. If you want to turn a shirt inside out, all you have to do is pull it through one of the shirt’s four holes: two arm holes, a neck hole, or the bottom. Most of the time you are dealing with a t-shirt in a situation where you can turn it inside out any way you want.
But in this experiment the goal is to turn a t-shirt inside out while wearing it and having your hands tied together. The fact that your hands are tied together is a constraint, meaning it is some sort of restriction on the problem. Now when you take off your shirt it is stuck on your arms. And it is impossible to turn it inside out the normal way because your arms get in the way. You can’t pull the top through the bottom or the bottom through the top. But that’s not the only way to turn a shirt inside out. It’s also possible to turn the shirt inside out by pulling it through one of the sleeves. If you pull the whole shirt through one sleeve, the constraint or your arms doesn’t get in the way. You are moving along the direction of your arms instead of against it so its possible to turn the shirt inside out. Now put it back on and you are all set!
Key terms
These are the key terms that students should know by the END of the two lessons. They do not need to be front loaded. In fact, studies show that presenting key terms to students before the lesson may not be as effective as having students observe and witness the phenomenon the key terms illustrate beforehand and learn the formalized words afterwards. For this reason, we recommend allowing students to grapple with the experiments without knowing these words and then exposing them to the formalized definitions afterwards in the context of what they learned.
However, if these words are helpful for students on an IEP, ELL students, or anyone else that may need more support, please use at your discretion.
- Topology: A type of math and physics that studies shapes and knots.
- Constraint: A restriction of some sort that usually makes a problem harder (and more fun!) to solve.
- Perpendicular: Two things are perpendicular when they are at right angles to each other.
Objective
Students will practice complex problem solving.
Before the experiment
- Ask & discuss
What might make it hard to turn the shirt inside out while your hands are tied together?
- Turn & talk protocol
- Pair students up.
- Give them a minute to think quietly.
- Give students 2 minutes to discuss their thinking.
- Have students record their answers or share out to the whole group.
Setting up
Separate the chopsticks and pick one to be your “stick person.” If you want, use the marker to draw a face on the stick person.
Take the plastic tie and attach it to the upper part of the chopstick using tape to make “arms.”
To keep them upright, use the “warpable spacetime simulator” (playdough) as a base.
Take the small cloth bag and hold it so that the opening is down.
The opening will be the bottom of the shirt.
Cut two small “arm holes” in the front of the shirt. Be careful to cut through the fabric of the front and not along the seams. Cutting through the seams will cause them to rip out.
Cut a “neck hole” in the top of the bag, again being careful not to cut through the seams.
If you’d like, draw a design on the outside of your t-shirt.
Turn the “shirt” inside out and put it on your stick person.
During the experiment
Make sure students are put into intentional groups. See Teacher Tip below.
Students will complete the experiment using the Student Guide where we have outlined the experiment for students and along the way, they record results and answer questions.
In the Student Guide, they will look at their data to describe which filters allowed each color through.
Continue to listen in on each group’s discussion; answer as few questions as possible. Even if a group is off a little, they will have a chance to work out these stuck points later.
Teacher tip
- Suggested STEP UP Everyday Actions to incorporate into activity:
- When pairing students, try to have male/female partners and invite female students to share their ideas first.
- As you put students into groups, consider having female or minority students take the leadership role.
- Take note of female participation. If they seem to be taking direction and following along, elevate their voice by asking them a question about their experiment.
- Consider using white boards so students have time to work through their ideas and brainstorms before saying them out loud.
- As students experiment, roam around the room to listen in on discussion and notice experiment techniques. If needed, stop the class and call over to a certain group that has hit on an important concept.
Consider using the RIP protocol (Research, Instruct, Plan) for lab group visits and conferring.
Consider culturally responsive tools and strategies and/or open ended reflection questions to help push student thinking, evidence tracking, and connections to their lives.
Conclusion
Follow the Write-Pass protocol to have students share and refine their thinking:
- Divide students into groups of four (different from their experimental groups).
- The teacher posts a question that students must answer with an explanation. What if you needed to turn your pants right side out with your legs tied together? Could you do that? What makes the t-shirt special?
- Students each write their own ideas on a loose piece of paper.
- Then pass the papers to the left.
- Each student silently reads the student’s response (and any of the other students’ comments, on iterating rounds of this process).
- Each student writes suggestions directly onto the original copy to help make their peers’ ideas sharper and clearer.
- Repeat the pass-read-edit until each student gets to read and comment on each other's ideas.
- The original author of each statement reads their peers' comments and writes a refined, final statement at the bottom of the paper to turn in.
After students have had a chance to discuss key ideas from the lesson and complete their student guides, you can now clarify and give concise definitions to the forces they experimented with.
- Real world connections:
- Allow students to play with the quantum logic games found here. Have them describe what the game shows and how they think this learning could be applied in their everyday lives.
- Suggestions for drawing, illustrating, presenting content in creative ways:
- Try the Wonders of Quantum Physics - Art + Polarization developed for the QuanTime project. They provide free kits and lessons.
- Engineering and design challenges connected to the content:
- Try some more advanced quantum games and lessons that explore logic gates and quantum circuits using the PhysicsQuest 2021: Introduction to the World of Quantum lessons (Mystery Tube, Particle-Wave Duality, Save Schrödinger’s Cat, Quantum Circuits).
- MS-PS4-3-applicationsCCC: Influence of Science, Engineering, and Technology on Society and the Natural World. Technologies extend the measurement, exploration, modeling, and computational capacity of scientific investigations. (MS-PS4-3)
- MS-PS4-3-nature-of-scienceCCC: Science is a Human Endeavor. Advances in technology influence the progress of science and science has influenced advances in technology. (MS-PS4-3)
- MS-PS4-1-empirical-evidenceSEPs: Scientific Knowledge is Based on Empirical Evidence. Science knowledge is based upon logical and conceptual connections between evidence and explanations. (MS-PS4-1)
Credits
Written by Rebecca Thompson, PhD
Illustrations by Kerry G. Johnson
Activity illustrations and graphics by Nancy Bennett-Karasik
Updated in 2023 by Sierra Crandell, MEd, partially funded by Eucalyptus Foundation
Extension by Jenna Tempkin with Society of Physics Students (SPS)