There are some places where the land is shaped in such a way that it can sometimes appear that things are going uphill when they are really going down. Some people attribute this type of activity to paranormal causes.
Jason Hoffman (Jason.Hoffman@nopc.jaxx.com) explains it this way:
"This was explained very simply on a TV show several years back. There is a place known as "Gravity Hill" where the road is on a slight decline. But the trees on the side of the road, instead of being vertical, lean down the hill. So that if you are standing sideways on the road, with the down side to your left, the trees `should' appear to lean to the right, but actually lean to the left. This makes the downward side of the hill seem to be the up side of the hill. The grade is so slight that it throws off your balance, so you become con- fused."This has been illustrated in fun houses at amusement parks...'The Leaning Room'. After being in the room for a minute, your natural sense of balance tries to correct itself. Then, you try to roll a ball down some parallel bars, but the ball rolls up instead."
Here is another explanation by Paul Johnson (paj@gec-mrc.co.uk):
"The brain uses a collection of techniques for deciding which way is up. The balancing organs in the inner ears only work when you stand still, so for most purposes the brain uses visual rules-of-thumb."Amongst these are:
- The ground is, on average, horizontal.
- Walls are vertical.
"So these mystery spots are usually on broad, empty plains with a slight slope. The slope isn't noticable, and rule 1 is applied by the brain to get a wrong answer for the horizontal. Hence any slight lessening of the slope looks like a slight upward rise on a flat plain, even though it is actually still downhill. So things rolling down the slope look like they are rolling uphill.
"Sometimes locals exploit rule 2 by putting up buildings that conform to the visual horizontal instead of the actual one. This reinforces the illusion quite strongly.
"If you are ever shown one of these spots, check a map with contour lines drawn on to find out how flat it really is."
FAQ EXTRA An excerpt from the USENET Physics FAQ on how things can appear to "roll uphill".
This page (http://www.ghosts.org/faq/5-7.html) last updated April 13, 2005.