Mobius Strip

Mobius Strip

Carefully cut out a strip of paper.Then cut two more strips.
Make a circle with one of the strips, then tape the ends together.
On the outside of the circular strip of paper, draw a red line in the middle all the way around the circle (or use some other color).Notice that the circular strip has two sides. It has an "outside" (with a line drawn around it) and an "inside" (with no line drawn on it). Draw a black line all the way around the circle near one edge. Notice that the circular strip has two edges (one with a black line near it, and one with no black line near it).
Carefully cut all the way around the middle of the circular strip (where the red line is in the pictures).Notice that you end up with two circular strips.
With another strip of paper, make a circle again but don't tape it yet.Imagine that one end of the paper has an X on the outside. Twist that end over so that the imaginary X is facing downwards, then tape it to the other end.
Now you have a circular strip with a twist in it.This is called a "Mobius Strip."
Draw a red line in the middle all the way around the Mobius Strip (or use some other color), just like you did with the circular strip.Notice that the Mobius Strip only has one side! It doesn't have an "inside" and an "outside" like the circular strip does! How is that possible? If you draw a black line all the way around the Mobius Strip near one edge, you'll see that the Mobius Strip only has one edge! How is that possible?
Carefully cut all the way around the middle of the Mobius Strip (along the red line in the picture), just like you did with the circular strip.Notice that it makes one large twisted circular strip instead of two circular strips!
With the third strip of paper that you cut out in step 1, make another Mobius Strip.This time, cut all the way around the Mobius Strip near the edge (where the black line is in the pictures above). Notice that this time you end up with two linked loops! Weird!