An Acidic Question for Shawn Carlson

I am a custom knife maker in Oregon. About 25 years ago I had some success in acid etching stainless blades with aqua regia. At that time I had a supplier of the necessary chemicals. I do not have that now.

I am wondering if I can cheaply make a test batch using sodium nitrate as a nitric acid substitute and either muriatic acid or some other hydrochloric acid substitute to make the batch cheaply? If so, might you also tell me something about safe and accurate measurements and preparation? Many thanks.

Bob

Shawn Replies

Dear Bob,

If I am recalling this correctly, aqua regia is a mixture of concentrated hydrochloric and nitric acids with a ratio of 3 parts HCL to one part HNO₃. Muriatic acid is just another name for hydrochloric acid. But sodium nitrate isn't nitric acid, so mixing them will not produce the so-called "royal water" you are looking for.

I believe you're going to need to find a source of nitric acid, and that's hard to do these days, because nitric acid is used in making explosives.

I don't know any "safe" way to make a dangerous substance. If you're successful, then, in the end, you'll have a venomous snake in a bottle that will bite you if you're not very very careful. The laboratory method of making nitric acid that I once learned proceeds by reacting equal weights of potassium nitrate (KNO₃) with concentrated sulfuric acid (as I recall). One needs to then distill this to separate the nitric acid from the potassium salt that is created during the reaction. The distillate is known as "red fuming nitric acid"--nasty stuff.

If you want to try this, you'll need to be extremely careful. For one thing, you must use all-glass equipment, because the nitric acid will attack rubber, cork, metal and you, if it gets on your skin. If you inhale the vapor deeply, you'll die a very painful death as the acid destroys the lining of your lungs. So this operation is usually carried out in a fume hood under great care.

I'm no expert on all this, but this is the best information I can give you, and it is offered with no warranty. I wish I knew of a commercial source of aqua regia, but I just don't.

Yours for great science,

Shawn Carlson, Ph.D.
Founder and Executive Director
Society for Amateur Scientists


Total Ozone Portable Spectrometer (TOPS) (from the SAS Forum)

Editor,

The latest "The Citizen Scientist" has a construction article on the Total Ozone Portable Spectrometer (TOPS). This was first published in November 1992 in Science Probe! magazine. I think I still have all the issues of Science Probe! but had forgotten about the TOPS article.

I really like construction articles like this. I may not actually build many of the projects, but I do like to see how others solve various problems when designing instruments.

The TOPS design calls for a Hamamatsu gallium phosphide photodiode (G1962) to be used for the detector. It took time to find information on this part. While looking, I found information on some other types of UV detectors. There are silicon carbide, gallium nitride, aluminum gallium nitride and titanium dioxide detectors for UV radiation. I suspect UV detector technology has advanced since 1992. All of these detectors have a fairly flat response in the UV range of interest and are blind to visible light. Boston electronics has a good bit of information on these various detectors at http://www.boselec.com/products/detuv.html. I especially like the TW30SX titanium dioxide detector.

Jim Hannon
http://www.fmtcs.com/web/jmhannon/

Readers, Jim posted this on the SAS Forum and gave permission to include it here. If you want to know more about the TOPS project and many other topics, please join Jim and me over at the SAS Forum. Editor.

More About TOPS

Editor,

Thanks for publishing the article on the TOPS instrument.

Since reading your editorial in the previous TCS, "Resolving to Begin a Regular Science Activity", I had been going over ideas for something to do. Most of the parts to build the VHS-1 haze meter are in a box in my workshop. So I went over what it would take to finish the project and take readings. The Concord web site still has the spreadsheets for doing the data entry and calculations. Then I remembered why I put the project in a box, I would not be able to take a daily reading because I would be at work during the week when the readings should be taken. The only way around this would be to make an automated instrument. This would be fun but it is a much larger and complicated project. One would need a motorized platform to point the instrument at the sun and a protective cover when not in use. A computer would have to be programmed to take and log the data. I can see that the TOPS and VHS-1 would be ideal in an educational setting where you want the students to have the hands on experience of data taking but not so popular with an individual who just wants to have and analyze the data. I have decided that for now I am going to just try and get a conventional weather station running and logging data. It should be easy enough to log wind speed, wind direction, temperature, humidity, pressure and rain. Any ideas on other measurements that could be made automatically?

Jim Hannon
http://www.fmtcs.com/web/jmhannon/

Readers, Jim has asked a great question. Do you have any ideas for environmental measurements that can be made automatically? Data loggers provide all kinds of possibilities. Silicon solar cells are cheap and have little drift. They are great for monitoring sunlight. Please send your ideas to Backscatter--and check out the SAS Forum for future discussion of the topic. Editor.

Geothermal Energy Research

Editor,

Geothermal energy research has become controversial lately. See, for example, http://www.renewableaccess.com/rea/news/story;jsessionid=1DDE410952821854D9A39FC2CD721880?id=47298

The two approaches I am aware of involve either directly harnessing the force of a steam well using a turbine or pumping a working fluid underground to recover subterranean heat.

There may be an alternative based on fiber optics. If buried sufficiently deep, it may be possible to"pipe" infrared radiation to PV units designed for lower wavelengths. This is a field known as thermal
photovoltaics: http://www.eetimes.com/story/OEG19981005S0025

Like most things, a great deal of research would be needed to see if this could be made into a cost-effective option for geothermal energy.

I see engineering as "skilled dreaming," science as "organized curiosity, and amateur science as the "ultimate form of critical thinking." Just doing some dreaming with all this.

Mark Valentine

Fire Ants Redux

Editor,

Regarding Paul Sagi's fire ant idea letter to "Backsacatter" in The Citizen Scientist, the English satirist, writer and amateur astronomer Terry Pratchett, has written several books which had a magical computer containing ants. The logo on the machine said "Anthill inside" ...... ;-)

Steve Taylor

Close to Nature

I try to do something to reduce atmospheric carbon dioxide. I grow and release marine and freshwater plankton into dead ocean and Puget Sound red tides, toxic lakes, polluted streams, and the Columbia River. The freshwater plankton absorb pollutants and radioactivity, die when they reach salt water, and are buried under sediments. The marine plankton produce atmospheric oxygen and are at the bottom of the food chain for fish and sea lions.

I increase vegetation on land by planting vegetables in rows that slope downhill two inches vertically per 100 inches horizontally (=2%). In dry weather, I let water trickle down the rows; in wet weather, rain or melted snow trickles down the rows, soaks into the soil and raises the water table. Today near Seattle, Washington, I have green kale, turnips, and onions grown from seed. Trees near the two percent rows grow rapidly. Sloping rows can reduce flooding, drought, and fires while increasing the spawning of fish.

In the past I have seeded sweet clover in cereal fields, planted rye in gardens as winter cover crop, and seeded annual ryegrass in autumn for winter lawns. If you travel with children, they can look at the landscape and identify public lands and privately-owned land: public lands are over-grazed or logged-off, barren with erosion; private lands are replanted and rotate grazing, weekly, like lawns.

Glen Alvin Hemerick

Thanks for the update, Glen. Your comment about public vs. private land depends on location. For example, in my part of Texas, tax rules for farmers and ranchers sometime require more animals per acre than the land will support. So some private land is badly overgrazed. Public land in Texas is reserved primarily for parks, not logging or grazing. These circumstances are the opposite of what you have reported for your area. Others might want to comment on this on the SAS Forum or in Backscatter. Editor.

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