Why does my paper Möbius strip have two sides instead of one?

[Imparcticle]

I tried making a mobeus strip (by taking a strip of paper, and turning it 180 degrees then connecting the edges). I drew a line on the strip prior to turning it and connecting the edges. The line appeared on one side and not the other...which is inconsisstent with the fact that a mobeus strip is supposed to have one side only. Mine had two.
How do I make one--accurately?
Why does it have only 1 side? How does this happen? How does it work exactly (not how its made please)?

 

[arildno]

You shall draw the line after you have made your Moebius band.
An untwisted strip of paper has 2 sides, so drawing your line prior to twisting it, will leave the other side blank. This part of the strip will remain blank even if you twist the paper.

 

[Imparcticle]

Is it just an illusion?

 

[arildno]

No, it is not!
If you do it properly, you will get a single, continuous curve that goes around its whole surface.

 

[killerinstinct]

I think the way you made it is wrong.
Here is how to accurately make a moebius strip.
1. Take a strip of paper.
2. Give it a half twist (turn one end over)
3. Tape the ends together.

 

[Gokul43201]

I tried making a mobeus strip (by taking a strip of paper, and turning it 180 degrees then connecting the edges). I drew a line on the strip prior to turning it and connecting the edges. The line appeared on one side and not the other...

Actually, the line appeared along half the length of the one side...not on one side out of two.