Has anyone used a propeller chip for supporting Chemistry experiments?

swampie777

I'm interested because I do demo's for boy scouts and girl scouts.

Thanks,

Swampie777

Leon

What sort of experiments?

Leon

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle

swampie777

The kind suitable for a demo. Kids like color changes, crystal growth, precipatates and the like. You have to steer away from flames and explosions (even small ones) or you'll raise parental ire. I'm thinking about electrochemistry specifically.

WBA Consulting

You might be able to leverage something off of the M-Sorter project in regards to demos surrounding color changes:

http://forums.parallax.com/showthread.php?p=806086

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Andrew Williams
WBA Consulting

Ale

I did put 2 on one of my thesis projects. But it is for serious experiments not for demos though . Btw, I'm a chemist.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Visit some of my articles at Propeller Wiki:
MATH on the propeller propeller.wikispaces.com/MATH
pPropQL: propeller.wikispaces.com/pPropQL
pPropQL020: propeller.wikispaces.com/pPropQL020
OMU for the pPropQL/020 propeller.wikispaces.com/OMU

4Alex

@Ale: Hi Ale, I'm an (organic) chemist too. Glad to see some colleagues on this forum. Do you also use the propeller in your lab like I do?

@Swampie777: What is your background and do you have access to chemicals? Presuming that you do, the next step is to realise what a propeller can do. A propeller can be used to control electricity: voltage and/or current, and also modulate a signal. So, if you want to associate these features with chemicals, you can achieve:

1. colour changes (at electrode's vicinity) either by galvanic effects (there's chemicals sensitive to electricity both in their crystalline - like tourmaline - and dissolved forms like potassium dichromate) or by local 'heating' (using cobalt chloride or cholesteryl salts, for example);

2. you can make a few loops of wire around a tourmaline crystal, pass some current and get electrostatic charges at the crystal ends which would attract or repel pre-charged styrofoam balls;

3. using the coloured liquid inside light sticks (essentially doped luminol), and two carbon electrodes, you should be able to generate bubbles of oxygen. With the right pH, this will result in chemical light (probably only in the vicinity of the bubbles, though, unless you shake the container). The light will not be as bright as from the breaking of the oxydising ampoule, but you should still get a spooky effect. The other electrode will generate hydrogen (twice the volume) so make sure you have some ventilation;

4. still using a somewhat conductive (electrolytic) water and two carbon electrodes near a pea-sized piece of white phosphorus (you should use this chemical only if you are a chemist yourself, though), you will generate a 'fire' under the water. Without oxygen, the process stops, so you could control the 'fire' using pulses;

5. still with electrodes, you can make a water solution of potassium sulphate, dextrose and methylene blue. After a few minutes, this liquid will become colourless. The blubling of oxygen will turn the liquid blue. Stop the oxygen and the liquid turns pink then colourless again;

6. powering a propeller-based circuit using a lemon (or even a potato) with a pair of copper and zinc wires. Voltage is low but you can use multiple pairs. In the same way, this could be used to control leds, sounds, etc. BTW, don't plan on getting megawatts with a lemon!

7. some chemicals reacts to sound pressure in water. A propeller could be used to control a piezoelectric element. A simple ultrasonic transducer immersed in water - and controlled by a propeller - will generate water vapour (i.e., smoke) and a small fountain.

8. there's many sensors and components out there that could be used in conjunction with chemicals. Also, inducing magnetic fields, controlled by a propeller, under a cardboard box or otherwise will create varying patterns of iron fillings.

It's a pity that you can't make explosions, fires, and the such as you would have a much broader spectrum of experiments. One doesn't really need to blow-up the roof to make safe and interesting demonstrations.

Anyway, just off my head.

Cheers,

Alex

4Alex

@Swampie777:

In addition to my last post, I was thinking that you could make a 'smelling' game using an array of heating elements activated by a propeller. If you deposit a small amount of various scents blended with some camphor (or any low MW waxes), upon sublimation you will get aromatised puffs. The simplest element could be an overloaded inefficient regulator, say a 3v3 on 12v. This should give a nice (and safe) heating effect. Pick one that has a control pin for on/off and tie it to a propeller. This should make an interesting game of scents guessing or whatever. I can provide you with a list of appropriate chemicals if necessary.

Boy, this is getting fun!

Cheers,

Alex

swampie777

Alex;

Thanks for your excellent suggestions. My background is Chemical Engineering. One of my favorite topics is electrochemistry, which several of your suggestions fit neatly into.

Thanks again,

Swampie777

tronsnavy

Here is the web site of Robot mag. http://www.botmag.com/. Thanks to Whit+ for sending it to me. In the spring 2008 issue, click on "Grant Imahara VEXPlorer Robot Challenge". Click on the First Place Video. The robot can mix chem while you are at a distance. Not sure if this is what you are looking for, but it might be able to get some ideas. It does not use a Prop.

Bob

Ale

I'm not using the prop in the lab that much, except for this particular machine I built. I couldn't mix as much electronics with chemistry as I wanted. Nice to see some colleagues here!.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Visit some of my articles at Propeller Wiki:
MATH on the propeller propeller.wikispaces.com/MATH
pPropQL: propeller.wikispaces.com/pPropQL
pPropQL020: propeller.wikispaces.com/pPropQL020
OMU for the pPropQL/020 propeller.wikispaces.com/OMU

tronsnavy

Sorry, just go to the web site and scroll down to "Grant Imahara VEXPlorer Robot Challenge". You don't have to go to the spring 2008 issue.

Bob

4Alex

@Swampie777: you are welcome. If you are interested in the oxygen production experiments, I've successfully used the carbon electrode from alkaline batteries. I clean them of any manganese dioxyde and electrolytic paste, then use a small pencil sharpener at one end to make a nice cone. This makes a very nice source of oxygen in electrolytic water.

@Ale: I'm getting lazy I guess. I often make little propeller sidekicks to monitor reactions while I'm busy doing some paperwork. pH, temperature, pressure, and conductivity are my friends in this. Trying to build an 'intelligent' cottage is more challenging, though.

Cheers,

Alex

Post Edited (4Alex) : 8/25/2009 3:49:18 PM GMT

Beau Schwabe

swampie777,

I'm not sure what level of Chemistry experiments you want to perform, but I thought I would throw this out there. In our fish tank after a water change we add Aquarium salt to the tank. The way I add it, you can visually see the difference salt water has verses fresh water. When I add salt, I place a clear plastic tube down into the rocks of the tank, while the other end of the tube is up out of the water. This is so the Fish don't try to eat the salt when I put it in the tank. The Tube is the same tube used to protect fluorescent lights and can be found at just about any hardware store. Anyway after placing the Aquarium salt within the tube, you can visually see the water displacement from the inside of the tube verses the outside of the tube, because the salt water inside the tube is denser than the fresh water outside the tube.

My thought was, is that if you could isolate this experiment and measure the water level displacement with a capacitive sensor... see link below, with the idea in mind that you could substitute the BS1 with a Propeller and lower the divider stage on the 4060 to get much more precision...

www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol1/col/nv27.pdf

... You could alter the aspect ratio of the "salt-tube" to get more displacement for the sensor above. The tube I have measures about 1-5/8 inches and 30ml of Aquarium salt will displace the water about 3/4 of an inch inside of the tube... about 1.6 cubic inches of displaced water.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 8/25/2009 5:01:36 PM GMT

4Alex

@Beau Schwabe:

You can realise a similar experiment (based on osmosis) using a big carrot and a aqueous solution saturated with sugar. Drill a 4in deep hole from the top of a topped big (I mean BIG) carrot. Fill the hole with a saturated solution of sugar. Press fit a 2ft tall rigid tube into that hole, making sure the sugar solution stays in the tube and the fit is very tight. Now immerse the carrot into a (preferably transparent) container of tap water. The level inside the tube will rise to at least 12in within about an hour or so due to the dilution of the sugar solution inside the tube by the tap water through osmosis. You can substitute the carrot with a potato, but it looks a bit odd. Using distilled water works even better. I used this trick many many years ago when performing science shows to school kids. It was presented as a 'magic carrot clock' given to me by no less than Bugs Bunny himself: we used the carrot clock to tell us when the ongoing show was over (I put marks on the tube and coloured the sugar solution with orange food colouring). Always a hit. If you use a rigid plastic tubing (NOT glass!), its then safe to remove the tube, slice the carrot, and distribute to the kids: they'll be very pleased with the sweetness of the magic treat

@swampie777: Since you like electrochemistry so much, I thought you could perhaps use electroplating with a propeller. Here's my idea: using photosensitised pcb, impress some funny patterns with uv on pcbs the size of baseball cards. If you also impress some traces to one edge too, you could snap these cards into an edge connector and pass a current. Using a clear etching solution you could dissolve the unprotected copper and 'reveal' the hidden pattern. wash & distribute to kids. They love collecting cards. Or, immerse in some plating solution and retain the whole metallic look, but in two shades. safe & very easy to achieve.

Cheers,

Alex

Post Edited (4Alex) : 8/25/2009 6:29:35 PM GMT