# Why does sand form dunes. **URL:** \ **Category:** Factual Questions\ **Created:** [February 29, 2000, 6:02am UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897 "2000-02-29T06:02:00Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Lexicon](https://avatars.discourse-cdn.com/v4/letter/l/ac8455/32.png) [@Lexicon](https://boards.straightdope.com/u/Lexicon)\ **Post date:** [February 29, 2000, 6:02am UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/1 "2000-02-29T06:02:00Z")
It was really windy today here in the big desert between Arizona and Texas. And there is a lot of sandy dirt near my work, as that is the only thing out there. Anyway, I noticed that a lot of the sandy dirt that was blown up against the buildings and gutter formed little dunes, this made me think of desert shots in movies and books and such. So I got to thinking… Why does sand form dunes? I don’t remeber finding a thread on this in all the archives I read during the time the MB was down, so if you find one, please post a link or lemme know! ---
**Author:** ![Zor](https://avatars.discourse-cdn.com/v4/letter/z/848f3c/32.png) [@Zor](https://boards.straightdope.com/u/Zor)\ **Post date:** [February 29, 2000, 9:31am UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/2 "2000-02-29T09:31:00Z")
I think this [article](http://www.sciam.com/askexpert/geology/geology3.html)sums it up pretty well… ---
**Author:** ![NanoByte](https://avatars.discourse-cdn.com/v4/letter/n/ecc23a/32.png) [@NanoByte](https://boards.straightdope.com/u/NanoByte)\ **Post date:** [February 29, 2000, 10:40am UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/3 "2000-02-29T10:40:00Z")
I though people with dune buggies made them with dune-making machines. Ray (. . .when they weren’t dune anything else.) ---
**Author:** ![TheUnforgiven](https://avatars.discourse-cdn.com/v4/letter/t/e480ec/32.png) [@TheUnforgiven](https://boards.straightdope.com/u/TheUnforgiven)\ **Post date:** [February 29, 2000, 5:27pm UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/4 "2000-02-29T17:27:00Z")
Zor, good article, but it deals more with sand waves than sand dunes, though they are somewhat related. I learned that sand has a certain coefficient of static friction (0.75) that allows it to “stick” to itself to form the dune shapes with the help of the wind. Because of this, the side of the dune that is not facing the wind will have an angle of 37 degrees with the horizontal. Thank you high school physics. * * * “The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents.” -H.P. Lovecraft, “The Call of Cthulhu” ---
**Author:** ![John\_Bredin](https://avatars.discourse-cdn.com/v4/letter/j/96bed5/32.png) [@John\_Bredin](https://boards.straightdope.com/u/John_Bredin)\ **Post date:** [March 1, 2000, 6:38am UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/5 "2000-03-01T06:38:00Z")
[obscure Chicago humor] You mean Insull didn’t create them to generate traffic for the South Shore Line? [/obscure Chicago humor] A tip of the hat to the person who can explain that joke. Two tips to anyone who laughed at it. (^: John B. “Moonlight in Duneland” Bredin, Esq. [jbredin@planning.org](mailto:jbredin@planning.org) ---
**Author:** ![Random](https://avatars.discourse-cdn.com/v4/letter/r/57b2e6/32.png) [@Random](https://boards.straightdope.com/u/Random)\ **Post date:** [February 29, 2000, 9:35pm UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/6 "2000-02-29T21:35:00Z")
Okay, I’ll bite. Insull was an early commuter rail tycoon in Chicago. The South Shore line ran (as the name indicates) south (more southeast) out of the city and into Indiana. To drum up weekend traffic, a famous series of posters were issued touting the Indiana dunes as a destination. Reprints are available at just about every shop that sells posters and prints in Chicago, especially those that attract tourist-types. Didn’t laugh, but did smile. Tip and a half? > [@](#): > > Originally posted by John Bredin: > \*\*[obscure Chicago humor] > > You mean Insull didn’t create them to generate traffic for the South Shore Line? > > [/obscure Chicago humor] > > A tip of the hat to the person who can explain that joke. Two tips to anyone who laughed at it. (^: > > John B. “Moonlight in Duneland” Bredin, Esq. > [jbredin@planning.org](mailto:jbredin@planning.org)\*\* ---
**Author:** ![John\_Bredin](https://avatars.discourse-cdn.com/v4/letter/j/96bed5/32.png) [@John\_Bredin](https://boards.straightdope.com/u/John_Bredin)\ **Post date:** [February 29, 2000, 10:05pm UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/7 "2000-02-29T22:05:00Z")
A smile is close enough. Two tips of the hat to you! John B. Bredin, Esq. [jbredin@planning.org](mailto:jbredin@planning.org) ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [March 1, 2000, 4:15am UTC](https://boards.straightdope.com/t/why-does-sand-form-dunes/7897/8 "2000-03-01T04:15:00Z")
Hey, I know this, because my family used to vacation in the NW part ot Michigan’s lower peninsula. ## [Here](http://www.leelanau.com/dunes/dunes/) is a link explaing the Ojibway legend. Sue from El Paso Experience is what you get when you didn’t get what you wanted.