Please help me solve this riddle . . .

[Luv2Travel]

Okay, I'm a high school Math teacher and I should probably know this, but I'm not getting it. My Assistant Principal asked me today: what can you make that only has one surface and one edge? In my earlier guessing I was lead to believe it had to be round (but I could be wrong about that) - but it wasn't a balloon. My next guess will be a solid ball. Does that sound right? Does anyone else have a guess?

 

[vivilasvegas]

A mobius strip.

 

[cakesnkids]

It's a mobius strip.
http://scidiv.bcc.ctc.edu/Math/Mobius.html

 

[buzzlady]

 

[cakesnkids]

Well crud, we musta been posting at the same time.

 

[vivilasvegas]

Well crud, we musta been posting at the same time.

Or googling at the same time!