# Science behind this trick...

**URL:** <https://boards.straightdope.com/t/science-behind-this-trick/382658>\
**Category:** Factual Questions\
**Created:** [December 3, 2006, 4:02am UTC](https://boards.straightdope.com/t/science-behind-this-trick/382658 "2006-12-03T04:02:20Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![CJJ](https://avatars.discourse-cdn.com/v4/letter/c/ecc23a/32.png) [@CJJ](https://boards.straightdope.com/u/CJJ)\
**Post date:** [December 3, 2006, 4:02am UTC](https://boards.straightdope.com/t/science-behind-this-trick/382658/1 "2006-12-03T04:02:20Z")

</div>

Watch [this video](http://video.yahoo.com/video/play?vid=f1b4c3cd85618fec3506971f0e2afae9.1241193&cache=1) (44 sec). The illusion is rather stunning IMO, but I’m wondering what the science behind it is. While I go looking for ten toothpicks, can anyone else duplicate this?

There are several comments talking about adhesion/cohesion of water, but they don’t sound very thorough; I think this could spark an interesting discussion…

---

<div class="post-metadata">

**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\
**Post date:** [December 3, 2006, 4:35am UTC](https://boards.straightdope.com/t/science-behind-this-trick/382658/2 "2006-12-03T04:35:35Z")

</div>

Adhesion/cohesion of water? I think they’re way off base. How about warping of wood.

Take a single toothpick, break it (but not in two), wet the break, and watch it straighten out. It’s the wood absorbing water and swelling.

---

<div class="post-metadata">

**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [December 3, 2006, 5:11am UTC](https://boards.straightdope.com/t/science-behind-this-trick/382658/3 "2006-12-03T05:11:51Z")

</div>

[QUOTE=Gary T]  
Take a single toothpick, break it (but not in two), wet the break, and watch it straighten out. It’s the wood absorbing water and swelling.  
[/QUOTE]

Absorption and swelling is also the basis of the [Straw-wrapper Snake Trick](http://www.youtube.com/watch?v=WUxp1hmNPZs).

---

<div class="post-metadata">

**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\
**Post date:** [December 3, 2006, 7:57am UTC](https://boards.straightdope.com/t/science-behind-this-trick/382658/4 "2006-12-03T07:57:57Z")

</div>

That is awesome and I will now be carrying round toothpicks in my pocket for the remainder of the holiday season.

Viva la science!!!

---

<div class="post-metadata">

**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [December 3, 2006, 5:05pm UTC](https://boards.straightdope.com/t/science-behind-this-trick/382658/5 "2006-12-03T17:05:51Z")

</div>

[Here](http://www.csiro.au/helix/experiments/dhexpstar.shtml) are instructions for doing the trick as well as the explanation (as already given by **GaryT** above).