# What scientific principle toy or project would you like to demonstrate to a bunch of kid? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [July 17, 2013, 3:17pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755 "2013-07-17T15:17:01Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 18, 2013, 2:48pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/21 "2013-07-18T14:48:55Z")
Magnets are always cool, and I’m personally quite attached to my [plasma ball.](http://en.wikipedia.org/wiki/Plasma_globe) ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [July 18, 2013, 2:51pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/22 "2013-07-18T14:51:54Z")
How about asking them: -Why do TVs need 3 colours, not 4 or 7? -Why are the primary colours of light and paint different? -Why doesn’t white+black = white? And then showing them a spectrometer? Very simple, yet these are very common questions, even on the board. Here are some pictures I took with mine: [https://lh4.googleusercontent.com/-gmjOd9GzPp8/UYPUaZyn7eI/AAAAAAABQYE/HPp886rzdKo/s0/the%252520true%252520nature%252520of%252520light.jpg](https://lh4.googleusercontent.com/-gmjOd9GzPp8/UYPUaZyn7eI/AAAAAAABQYE/HPp886rzdKo/s0/the%252520true%252520nature%252520of%252520light.jpg) ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [July 18, 2013, 4:51pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/23 "2013-07-18T16:51:59Z")
I want to add in a plasma speaker. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [July 18, 2013, 5:06pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/24 "2013-07-18T17:06:39Z")
Make [ferrofluid](http://onehundredkbucks.hubpages.com/hub/How-To-Make-Magnetic-Fluid) (magnetic fluid) with laser toner and vegetable oil (though I’m somewhat doubtful this works as advertised; alternatively, there’s also places online you can buy the stuff). A timeless classic is the flip top: a top that, once spun, flips itself around to continue spinning on its handle. [Pauli and Bohr](http://www.wissenschaft-shop.de/out/pictures/wysiwigpro/802265_Pauli_Bohr-Wendekrei.jpg) seem to have liked it! ---
**Author:** ![spotthegerbil](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@spotthegerbil](https://boards.straightdope.com/u/spotthegerbil)\ **Post date:** [July 18, 2013, 5:07pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/25 "2013-07-18T17:07:38Z")
> [@Harmonious\_Discord](#): > > You require a high temperature burn to start the reaction or every kid would have used it. We were certainly aware of the high temperatures required for ignition. In another experiment, we used the element required for thermite ignition to do something that resulted in the melting of a test tube. Nobody was ever injured in our school, as they took safety seriously, but we got to see some cool stuff. As children we are told “do not try this at home” but as adults the advice is often “hold my beer and watch this!” 😃 For a less dangerous, but pretty science experiment, do chromatography. Use a not too dangerous solvent to show the different colours in a coloured ink stain. Use the chromatography principles to show different types of chlorophyl in leaves by grinding up different leaves in solvent and seeing how they migrate over paper. ---
**Author:** ![california\_jobcase](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)\ **Post date:** [July 18, 2013, 5:38pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/26 "2013-07-18T17:38:55Z")
Vis-a-Vis brand overhead projector markers are great for paper chromatography. Use white paper towels and water. ---
**Author:** ![deltasigma](https://avatars.discourse-cdn.com/v4/letter/d/e5b9ba/32.png) [@deltasigma](https://boards.straightdope.com/u/deltasigma)\ **Post date:** [July 18, 2013, 5:39pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/27 "2013-07-18T17:39:52Z")
> [@Half\_Man\_Half\_Wit](#): > > Make [ferrofluid](http://onehundredkbucks.hubpages.com/hub/How-To-Make-Magnetic-Fluid) (magnetic fluid) with laser toner and vegetable oil (though I’m somewhat doubtful this works as advertised; alternatively, there’s also places online you can buy the stuff). > > A timeless classic is the flip top: a top that, once spun, flips itself around to continue spinning on its handle. [Pauli and Bohr](http://www.wissenschaft-shop.de/out/pictures/wysiwigpro/802265_Pauli_Bohr-Wendekrei.jpg) seem to have liked it! Probably a parity flipping top. IDK. Started on a new book that might actually explain parity. Susskind’s book seems like the scenic route that only gets you to the departure terminal. 🙂 ---
**Author:** ![Tangent](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tangent/32/3098_2.png) [@Tangent](https://boards.straightdope.com/u/Tangent)\ **Post date:** [July 18, 2013, 5:45pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/28 "2013-07-18T17:45:04Z")
> [@Half\_Man\_Half\_Wit](#): > > A timeless classic is the flip top: a top that, once spun, flips itself around to continue spinning on its handle. [Pauli and Bohr](http://www.wissenschaft-shop.de/out/pictures/wysiwigpro/802265_Pauli_Bohr-Wendekrei.jpg) seem to have liked it! You can buy flip tops or “tippy tops” but a high school or college class ring will usually work. Start it heavy-side-down and give it a good spin and it will soon flip itself. ---
**Author:** ![glee](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@glee](https://boards.straightdope.com/u/glee)\ **Post date:** [July 18, 2013, 6:38pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/29 "2013-07-18T18:38:18Z")
[You’ll need a table, many bottles of Diet Coke and lots of Mentos](https://www.youtube.com/watch?v=hKoB0MHVBvM2) … and lots of help clearing up. :eek: ---
**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\ **Post date:** [July 18, 2013, 6:49pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/30 "2013-07-18T18:49:50Z")
I actually had such an opportunity. I was working in the newsroom at a radio station when a school bunch came through. I had a network feed that came in, and the option of receiving it over a land link or a satellite feed. I turned them both on at the same time, to record them simultaneously, out of synch. I marked the tape at the spots where a tone started on each of the two feeds, measured the distance between the two marks, at 7.5 inches per second, and showed them how to determine from that and the known speed of light, the height of the satellite that relayed the feed. ---
**Author:** ![dataguy](https://avatars.discourse-cdn.com/v4/letter/d/eada6e/32.png) [@dataguy](https://boards.straightdope.com/u/dataguy)\ **Post date:** [July 18, 2013, 9:46pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/31 "2013-07-18T21:46:08Z")
Gyroscope ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [July 19, 2013, 2:28am UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/32 "2013-07-19T02:28:18Z")
Cheap faster than light travel. I’d really light to be able to demonstrate that to a bunch of kids. Sigh. ---
**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\ **Post date:** [July 19, 2013, 6:21am UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/33 "2013-07-19T06:21:16Z")
Vortex rings. [The Vortex Cannon - Student Science - YouTube](https://www.youtube.com/watch?v=4b2SV3ASUxY) ---
**Author:** ![Max\_Torque](https://avatars.discourse-cdn.com/v4/letter/m/e9bcb4/32.png) [@Max\_Torque](https://boards.straightdope.com/u/Max_Torque)\ **Post date:** [July 19, 2013, 2:26pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/34 "2013-07-19T14:26:58Z")
Oxygen takes up space: fill a shallow pan with water, put a lit candle in the middle of it (not so much water that the candle floats). Put a jar over the candle. The candle will run out of oxygen in just a few seconds and snuff itself, and then the water level inside the jar will rise as water comes in to take up the space of the missing oxygen. And there’s the fun [egg in a bottle experiment](http://www.stevespanglerscience.com/lab/experiments/egg-in-bottle). ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [July 19, 2013, 2:30pm UTC](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755/35 "2013-07-19T14:30:54Z")
> [@Max\_Torque](#): > > Oxygen takes up space: fill a shallow pan with water, put a lit candle in the middle of it (not so much water that the candle floats). Put a jar over the candle. The candle will run out of oxygen in just a few seconds and snuff itself, and then the water level inside the jar will rise as water comes in to take up the space of the missing oxygen. Common misconception, the water level rises because the air cools and shrinks once the flame goes out. e.g. [Science Kits & Science Toys | Steve Spangler Science](http://www.stevespanglerscience.com/lab/experiments/why-does-the-water-rise) [Previous page](https://boards.straightdope.com/t/what-scientific-principle-toy-or-project-would-you-like-to-demonstrate-to-a-bunch-of-kid/663755.md?page=1)