| From: Liz | 19/08/99
20:54:04 |
| Subject: rolling up hill??? | post id:
31769 |
| O.k. I know this sounds weird,
but last year while in Northern Chile with my boyfriend I went to a place
in the Attacama Desert called Lauca National Park. I went on a day trip
with a mini bus load full of other tourists and on our way down the
mountain (Lauca is at about 5000m asl), throught the desert the mini bus
stopped, became totally stationary and the engine was turned off. We then
proceeded to roll up hill. I didn't speak a whole lot of Spanish at this
stage so managed to miss most of the guides explanation and have continued
to be spun out for the last year or so. So tell me... Why is it
so???? | |
| From: Daryn Voss (Avatar) | 19/08/99
21:00:44 |
| Subject: re: rolling up hill??? | post id:
31771 |
| I can't speak about this
particular place, but any of these that have been carefully examined have
proven to be optical illusions. A common cause is that a lot of the
surrounding trees are all at a slope (Why? Beats me.) But get out your
spirit level, your theodolite, plumb bob and protractor and sure enough,
the vehicle is miraculously rolling downhill. When you are sitting down in a bus, you don't get as much of a sense of grav as when you are standing so you have to rely on visual clues. Next time you are there, ask to get out of the bus. Of course, this one place sould be the exception, and the bus is rolling up hill because of ghosts or aliens or something. I'm just talking about the general case. | |
| From: Lisa | 19/08/99
22:18:18 |
| Subject: re: rolling up hill??? | post id:
31778 |
| I don't have a real answer for
you, but the same thing happens at a place called Magic Mounitan out near
Windsor in NSW. We poured a bottle of water on the road there and lo and
behold, the car was indeed rolling down hill even though it looked like it
was going uphill. Lisa | |
| From: The Swamp | 19/08/99
22:31:34 |
| Subject: re: rolling up hill??? | post id:
31781 |
| The sensation of the vehicle
rolling uphill or backwards for that matter can easily achieved by looking
out the back of a forward moving vehicle for at least ten minutes. I have
noticed this after travelling in the back of an army truck watching
backwards. One time (after the truck stopped) i jumped out and promptly
fell over. Its all visual! | |
| From: Andrew | 20/08/99
12:00:05 |
| Subject: re: rolling up hill??? | post id:
31860 |
| Trees on a slope are usually due
to the prevailing wind direction, or something blocking sunlight on the
opposite side to the direction they
point. | |
| From: liz | 20/08/99
14:32:57 |
| Subject: re: rolling up hill??? | post id:
31895 |
| A point of further clarification,
we were in the Attacama desert where it has never rained so there were no
trees. Not even cactus! Also, there was no wind that day, any more
ideas?? | |
| From: Daryn Voss (Avatar) | 20/08/99
16:39:10 |
| Subject: re: rolling up hill??? | post id:
31932 |
| Liz, I have to ask: what is it
that let you know that the direction of the bus is uphill? What was your
reference to the vertical? | |
| From: maj-lis | 20/08/99
23:17:13 |
| Subject: re: rolling up hill??? | post id:
31990 |
| there is another place in
victoria where this happens it is on straws lane past macedon just before
the hanging rock turn off | |
| From: liz | 23/08/99
9:29:38 |
| Subject: re. Rolling up hill??? | post id:
32170 |
| Darryn, we were at the bottom of
a depression and had just driven down one side, so I had that as my
basis... Any help?? | |
| From: Martin B | 23/08/99
11:02:47 |
| Subject: re: re. Rolling up hill??? | post id:
32187 |
| Hi Liz And you rolled 'up' the other side of the depression to the one you drove down into it? The question remains: How did you know that you were at the bottom of the depression? How do you know that the 'depresssion' wasn't a point where the slope changed from very steep downhill to very gradual, but still downhill? Did you get out of the car and perform any other measurements? Or was this all based on visual inspection of surroundings from inside the car? Hope this isn't coming across as accusatory or something, it's just that as Darryn has pointed out every investigated place like this has turned out to be one where the visual clues about 'down' were misleading. If we can find a place that is dinky-di as you describe then we're onto something... | |
| From: Liz | 24/08/99
11:26:41 |
| Subject: re: re. Rolling up hill??? | post id:
32339 |
| Hi Martin, Hmmmm, interesting questions and yep, my observations were based solely on visual clues. Does that mean I'm seeing things? They guy seemed to think it was something to do with magnetism as "magnetico" was the only thing I really picked up from his blurb... What do you think? | |
| From: steve(primus) | 24/08/99
11:47:16 |
| Subject: re: re. Rolling up hill??? | post id:
32341 |
| Liz, if you click on faq
on the pink bar between Help and K2, you will find earlier posts on this
same subject (you will have to scroll down to the second set of
questions) BTW it has rained in the Atacama Desert, but not very often. The driest place in the world is Arica in Chile with an average annual rainfall of 0.8mm. The longest it has gone without rain since records started was 15 years. | |
| From: Daryn Voss (Avatar) | 24/08/99
12:12:58 |
| Subject: re: re. Rolling up hill??? | post id:
32346 |
| Hi, Liz. It doesn't mean you are
seeing things. A shallow depression in a hill that is has a minimum like
this \_/ looks pretty much the same as a shallow depression that looks
like this ! _/ (hope the formatting turned out okay: angles exaggerated so that I could type them.) The most natural (common?) thing to think when something like that is viewed is that you are in a depression that goes down and then back up, rather than down at a shallow slope and then down at a less shallow slope. The only way you could really tell the difference is by having some reference to up/down. Sitting down in a bus, it is hard to tell whether the bus is horizontal or maybe 2 degrees off horizontal. If you had got out and got your bearings, you may have felt differently (especially if you had a spirit level or a plumb bob, or some other means of determining the vertical.) As I said before, I'm just talking about the general case of these things. This place in South America may genuinely be something different. I have another question: were you able to see a flat horizon? If so, then it might be some other effect. | |
| From: liz | 25/08/99
9:40:29 |
| Subject: re: re. Rolling up hill??? | post id:
32479 |
| Steve, re. Arica, Chile. Thats the town we left from on our little expedition to roll uo the hill, maybe the Chileans just tell all the tourists its never rained as many of them have never seen it??? | |
| From: steve(primus) | 25/08/99
10:24:55 |
| Subject: re: re. Rolling up hill??? | post id:
32480 |
| They might have seen it Liz, but
the chances of the tourists seeing it are minimal so it makes a good
story. I have no trouble with locals stretching the truth a bit - like the
guy in Kenya who demonstrates the coriolis effect at the equator, and I
would be the last person to point out where they were wrong. An average
rainfall of 0.8mm per annum is so close to bugger-all it might as well
be. | |
| From: Miguel | 1/07/99
12:11:21 |
| Subject: Rolling up a hill | post id:
21271 |
| Hi everyone... I live in Perth. When I was younger..at school we had an outing to a little back road in Forrestfield. A bus full students parked at the bottom of a small but definate hill rolled up...engine off..I thought is was a trick but I recently visited the same hill and my car rolled up the hill about 30 meters...what could cause this...it is not an optical illusion | |
| From: Daryn Voss | 1/07/99
12:20:29 |
| Subject: re: Rolling up a hill | post id:
21279 |
| ,
In answer to your query: I am now itching to go to one of these places. When I do, I will take i) A plumb bob ii) A spirit level iii) some basic surveying equipment. I have to ask: How did you ascertain that it wasn't an optical illusion? | |