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Author: Subject: Chemical Demonstration Idea Suggestions
mrjeffy321
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[*] posted on 8-3-2010 at 20:38
Chemical Demonstration Idea Suggestions


I have been given the opportunity to put on a chemical demonstration show for a general audience in a couple of weeks. I would like to design the show around a few (~2 to 4) visually impressive chemical demo reactions that I would be able to explain to a crowd of lay people (who might have some amount of technical expertise, but generally no chemistry knowledge). The demo reactions would be viewed from a distance by the crowd and in full daylight, so it cannot be anything which requires one to be close by or in the dark in order to appreciate it. Also, the required materials must be portable, so no big equipment or materials which will not transport well (like liquid nitrogen).

I have decided that the grand finale of the show will be a large thermite reaction, but I cannot think of anything else which might lead up to this. Most of the stuff I can think of off the top of my head that I could do easily requires someone to be standing relatively nearby in order to appreciate (since it is small), or is too dangerous to do in this type of setting.

Reactions involving fire are OK, as long as it is controlled and done safely (hence the need for a large separation distance from the crowd), but explosions are probably not; it needs to be believably safe to the organizers who must approve what I will do.

Has anyone else done something like this before? What worked well for you? Or does anyone else have suggestions for demos that I might try?
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rrkss
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[*] posted on 8-3-2010 at 20:43


Dissolving Styrofoam in a solvent usually has gotten wows for me. Acetone and Ethyl Acetate are two cheap solvents that you can use to dissolve a coffee cup.
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IrC
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[*] posted on 9-3-2010 at 00:01


Reactions that look cool might be good such as the oscillating Briggs-Rauscher reaction. Here is a link :

http://chemistry.about.com/cs/demonstrations/a/aa050204a.htm

And never forget the Chemical Volcano :

http://chemistry.about.com/cs/demonstrations/a/aa033003a.htm

For other visually appealing experiments do a "Google" search on the term "clock reactions". Also who could overlook the fun of burning sodium in water, small amounts would be fairly safe. IIRC there is another clock reaction involving potassium permanganate but you will need to search as I do not remember the specifics. Of course who could forget the fun of adding glycerin to your leftover potassium permanganate.

At least that is a start and I am sure many other ideas exist out there in internet land. One idea to start is to google the keywords "chemical demonstrations".


Instant Fire is another idea :

http://chemistry.about.com/od/demonstrationsexperiments/ht/i...

Demonstrations which are a little dangerous are usually more entertaining.




"Science is the belief in the ignorance of the experts" Richard Feynman
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psychokinetic
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[*] posted on 9-3-2010 at 00:32


I'm a fan of elephant toothpaste and sodium ethanoate sculptures.

I was introduced to both of these from a fellow member :)

http://www.youtube.com/watch?v=6qNh5t-MaoA if his elephant toothpaste.




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Ozonelabs
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[*] posted on 9-3-2010 at 02:41


Elephants toothpaste on a large scale is usually impressive.
Copper oxide/ magnesium reaction is good.
Hydrogen oxygen baloons (or acetylene oxygen if you can be 'safe' about it)
Large scale alkali metals doesn't quite seem appropriate
Silver Nitrate and magnesium powder initiated by a drop of water
Bromine and aluminium
Bromine and red phosphorus
Iodine and pinene
Flexible glass rod by HF immersion

There's masses you can do!




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per.y.ohlin
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[*] posted on 9-3-2010 at 03:41


Water starts a fire?
Ammonium nitrate/zinc dust composition with a small amount of a chloride. Add a drop of water and it ignites.:cool:
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dann2
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[*] posted on 9-3-2010 at 04:38



Hot ice (from Sodium Acetate). Not really a 'true' chemical reaction though.
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Picric-A
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[*] posted on 9-3-2010 at 09:24


AgNO3/Al would be expencive on large scale! :O
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mrjeffy321
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[*] posted on 9-3-2010 at 11:21


Thank you for the good suggestions.

I like the idea of doing a large scale 'elephant toothpaste' and 'clock reaction' demo. Ammonium nitrate and zinc might also be good too.

The conclusions someone might incorrectly jump to if they knew that I was transporting all these materials (concentrated H2O2, and other strong oxidizers, iodide salts, powdered metals, acids) has crossed my mind.
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Skyjumper
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[*] posted on 9-3-2010 at 12:12


The permanganate reaction you mentioned above is simple (im actually showing my class it tomorow)

1. Take a flask (bigger=better) fill it with dH2O and add a *few* crystals of potassium permang. Enough to make a nice violet solution.
2. Take another flask, make it alkaline (I had luck with a decent "splash" (20-30ml?) of 6m NaOH fill it with water, and disolve in it a couple scoops of sugar (sucrose) I used alot, the amounts arnt important. Heat to dissolve it all. When ready, add flask 1 to flask 2. Awesomeness ensues.
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IrC
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[*] posted on 9-3-2010 at 17:20


Quote: Originally posted by mrjeffy321  
The conclusions someone might incorrectly jump to if they knew that I was transporting all these materials (concentrated H2O2, and other strong oxidizers, iodide salts, powdered metals, acids) has crossed my mind.


Two things. Since you are in Texas carry no glass, and talk very slowly.




"Science is the belief in the ignorance of the experts" Richard Feynman
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Skyjumper
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[*] posted on 9-3-2010 at 19:00


Unless you have a permit! because, you know a beaker is more dangerous than a semi automatic rifle these days. Y'know what them chemists been up too.
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blogfast25
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[*] posted on 10-3-2010 at 14:40


* Spraying the audience with liquid nitrogen. Surprisingly 'uncold'... Totally safe. Eery... And dry too!

* Giant (over 1 m long, 2 inch D) test tubes filled with hydrogen: ignite, loud bang, see the reaction front move quickly through the length of the tube. Visible from several meters away. Very impressive. Very safe. Repeat as often until they've had enough. Watch them cow away with anticipation of the Bang!

* Various chemical clocks: 1 gallon demijohns are well visible from a few meters away. Mysterious! Blue turns white, then shake for more blue... Abracadabra... Let them run during the whole demo...

* Burn large amount of magnesium powder. Optional: mix in some iodine for purple smoke.

* Green flame: boron trimethylate in alcohol burns green...

This kind of thing requires showmanship, so get your Liberace hat on!



[Edited on 10-3-2010 by blogfast25]
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mrjeffy321
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[*] posted on 10-3-2010 at 15:41


I appreciate the suggested demonstrations.

But I would like to pose the question another way now. Instead of thinking of it merely as an even to entertain people with how “cool” chemistry can be, why not teach them something too. By teach, I do not mean just explain what is happening in the reaction but rather teach them how to do or make something.

I would assume that most amateur-chemists would agree with my when I say that this hobby of ours gives us a lot of practical experience with chemistry. If there was one bit of your chemistry knowledge you could pass onto someone, what would it be? Would it be how to synthesize your favorite type of salt, extract something from an everyday product, …
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Skyjumper
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[*] posted on 10-3-2010 at 18:53


Easy to teach the concept of: take hair product (shampoo) separate it with water and toluene. (Could explain solubility, how certain ingredients in the product are soluble in water more than toluol and vis versa)
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blogfast25
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[*] posted on 11-3-2010 at 08:22


With all due respect mrjeffy321, I think you may be aiming too high. I'd make the entertainment value high and more or less forget about the educational component. And in any case each of the suggestions here made represent a physical/chemical principle that can be very briefly explained.

The shows I've seen with my High School daughter, performed by professional chemists, emphasised entertainment and were splendid; a delight for young and old alike: people tend to be wowed more by a guy hammering a nail in a plank with a banana (previously frozen by means of liquid nitrogen) than by a simple explanation of Elephant Toothpaste...

Just my two cents...

Or perhaps you could very briefly explain the main activities of chemists: separation - reaction - synthesis at the very start of the show and then during the show explain into which category each demo falls?


[Edited on 11-3-2010 by blogfast25]

[Edited on 11-3-2010 by blogfast25]
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mrjeffy321
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[*] posted on 13-3-2010 at 11:31


Yes, blogfast25, you may well be right. I think I should just keep it short and simple.
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Skyjumper
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[*] posted on 13-3-2010 at 12:57


Silvering a container may be cool too (on a large scale, say a 1k ml flask. Have a contest to get rid of it. (who knows why *insert simple chemistry demo here* works?)
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