Mark Andy
>
> You've got a water level, with all its tubing, on a
> table. The two ends are held up against a wall and
> you mark where the water is.
>
> Next you take all the tubing on the table and drop
> it on the floor. The water level just got lower
> (on both ends), right?
Nope. The volume of water in the tubes is exactly the same, so the
water level doesn't change on the ends. If you raise and lower the
entire "system", including the ends, then things change. But water
always "seeks its own level", so if you fix one end, the water level at
the other end will always be level with that end.
Mark both ends of the tube when they are next to each other. Attach one
end to a fixed post, and move the other end around. if the other end is
physically lower, the water will be higher in that tube and lower in the
fixed end, but they will be even. Raise the moveable end until the
water is at the mark, and it will be at the same level as the other end,
and the two marks will be level.
No matter what the water is doing in between, the water level in the
ends of the tube will be level to each other. Raise and lower the
movable end until the marks line up and you will have level marks.
Here's one write up: < http://www.buildeazy.com/fp_waterlevel.html>
Tim Mullen
|