Inside: The Mobius strip is one of my favorite science-y math activities. It’s inexpensive to make, packed with educational value, and super exciting for kids (and me!).
Do you love the idea of bonding with your kids over science but dread the effort? The Mobius strip to the rescue!
All you need is about 10 minutes out of your day and a piece of paper to show your kids the magic of science in general and the wonder of math in particular…
The mathematical mystery of the Mobius strip started in 1858 when the German astronomer and mathematician Mobius came up with the Mobius strip. (I should mention for the record that another German mathematician, Listing, came up with the same idea independently at the same time, but unfortunately for Listing, the discovery was named after Mobius).
A Mobius Strip is:
- Puzzling, and
- A bit out there.
When you do this activity, your kids practice:
- Observational learning,
- Science skills (hypothesizing possible outcomes and verifying predictions),
- The relationship between objects, and
- Math concepts (such as area, surface area, surfaces, and edges).
Some good questions you can ask during the investigation:
- What’s going on here?
- How did the twist work?
- Why does the strip have only one side?
- How do they connect?
- What happened when I did this?
- Where did the line go?
- Why did the strip not separate into two rings when we cut down the middle?
What you need:
Note on Paper (No pun intended)
Although we made our Mobius strip from scrapbook paper, you can make it from any paper – typing paper, newspaper, craft paper, wrapping paper, or tissue paper.
I prefer to use paper that looks different on each side so that kids can see clearly what happens with the twist. But you can also just use a pencil to mark one side for clarity.
What to do:
1. Measure and Cut
Measure and cut a few strips of paper that are at least 6 inches long.
2. Master the Flip
Point out that the strip of paper has two sides: the front side and the backside. Demonstrate to kids how to bend the strip of paper into a loop, then flip one side from front to back and tape both ends together. If this sounds confusing, watch my video below.
Let kids practice with all the strips of paper you cut in step one.
3. Draw a Line
Using a permanent marker, draw a line (parallel to the edges of the strip) without lifting the pen. Did you end up in the same spot where you started?
Tell kids to trace the drawn line with their fingers. How many sides does the Mobius strip have now?
4. The Magic Part
Now, take scissors and cut along the line you just drew.
What happened now?
Contrary to what most people expect, cutting the Mobius strip in half doesn’t result in two strips. It makes it longer.
But wait, this new longer strip is not a Mobius strip anymore…
Don’t believe me?
Try to trace it with your finger along the centerline again as we did in step 3. It doesn’t work, does it?!
If you want to delve deeper into the mystery of the Mobius strip, visit Math Educators’ idea exchange.
Are you a visual person? Here is a video!
You can stop the investigation here or use the Mobius strips you created during the above steps to make a Mobius strip mobile.
How to Turn Mobius Strips Into a Mobius Strip Mobile
1. Tie two sticks together in the shape of a cross.
2. Cut a string to the desired length, and then measure out three more of the same length.
3. Tie one end of each string to the branch and the other end to the Mobius strip. We found that paper clips made it easier.
Balance your mobile. It might take a while, especially if your sticks are slightly different in weight.