Math with scissors
The other day I visited my son’s class and did the following math demonstration.
Take a strip of paper and draw a line down the middle. Our line is red.
Tape one end to the other, but put a “half twist” in it, just like shown here. This is a Moebius strip. It only has one side to it. A pretty cool object in and of itself.
Now for some real fun. Take a pair of scissors and cut the Moebius strip in half along the red line–But before you do that try to guess what you will end up with!!! I’m not going to show you. You have to try it yourself. Just make sure that you only cut along the red line!
In the end what do you get?
(Make a guess first.)
One more: Make a star shape just like this. Make sure that all of the strips are the same length and that the angles between the strips are the same. Draw three red lines. One down each of the strips.
Now for the tricky part. You have to do this part right to get nice shapes in the end. But, don’t worry too much. If you do it “wrong” you’ll just get something other than what we got. Flip your paper over. Tape the last two opposite ends with a full twist to the left. Just like shown here.