Where can I find a level surface?

I'm trying to calibrate a digital level, and doing this entails
setting it on a perfectly level surface. Of course, if I could tell
which surfaces were perfectly level, I wouldn't need this damn thing
in the first place. Is there something really obvious I'm overlooking?
Or will i need to revert to the sorts of disasters I'm envisioning
involving balancing it on a seesawlike contraption or trying to set it
on the surface of water?


Anonymous said...

The truest level will come from using water. It won't be that hard to do.

Chris said...

What good is a science project if it doesn't involve fun and dangerous materials? Float a plate of glass on a puddle of mercury.

For a more practical solution, place the level on a surface that is approximately level. Then calibrate it to zero. Now pick it up and turn it around 180 degrees and put it down again in the same spot. If it still reads zero, then the level is calibrated (and, incidentally, the surface was level). Otherwise, adjust the calibration to take out half the error. Now your level is calibrated.

As a geeky aside, given a point on any flat surface, you can draw a line through that point that is level.