Global Warming Solution?

Most educated people in the world today are familiar with the “Nuclear Winter” concept. The cause of a nuclear winter would be the vast amount of dust carried into the stratosphere by the mushroom clouds of nuclear explosions. I have heard that there are now non-nuclear bombs that are as powerful as nuclear bombs. These bombs, so I understand, produce mushroom clouds too, but these mushroom clouds are not radioactive. If we were to set off enough of these mushroom cloud producing, non-nuclear explosions on a regular basis, the cooling effect of the dust injected into the upper atmosphere might cancel out the effect of the excess amounts of greenhouse gases in our atmosphere?

I’m not a climatologist, so I can’t say whether or not this is a practical and valid way to reduce global warming. I would be interested to hear what the real climate experts would have to say about this idea.

Robert A. Warren

Thanks for sending your idea, Bob. A host of ideas to reverse increasing temperature have been proposed by scientists, including injecting reflective particles from aircraft and launching reflectors into space. The consequences of some or most of these ideas might be worse than the problem they are supposed to cure. Readers, please send your ideas to Backscatter or start a discussion at the SAS Community Forum. Editor.

Technical Question for Shawn Carlson

Shawn,

In regard to your “The Amateur Scientist” article on building a natural electromagnetic wave detector (Scientific American, May 1996), I have a few questions about construction of the device:

In the circuit schematics, no wattage or tolerance ratings for the resistors is listed. What should they be?

The circuit schematics show two IC chips (op amps?), OP-07 and OP-470Y. I can't find a manufacturer using those numbers. Can you give me a source/manufacturer for those IC's?

Regarding the antenna, you mention winding 20 layers on a 2-feet rod. For purposes of purchasing the right amount of wire, do you have any idea what the total length of the wire would be?

David Clemens

Shawn Carlson Replies

Hi Dave,

The wattage ratings on the resistors do not matter. The power consumption is so low that any resistor you can find will be well able to tolerate the tiny amount of power generated. As to
tolerance, I used 5% in the original device, but these days I recommend 1% resistors.

The op amps may no longer be manufactured. You need ultra-low noise op amps. Go to the Analog Devices web site and see what they are selling in low noise op amps these days. I suspect that whatever is now their low noise standard will do great things for this application.

About the length of wire, it depends entirely on the thickness of the wire you select. Once you know the thickness, the total length is relatively easy to estimate. What would the radius of widest loop be if you coiled 20 loops on the rod? Then take the average of that number and the radius of the rod itself. That will tell you the average loop radius. From that you can calculate the average loop circumference. Then calculate the total number of loops required (20 loops per position x the number of single loops that will fit on the 2-foot rod.) The total number of loops x the average circumference of the loops will provide you with an excellent estimate of the amount of wire required.

I hope this helps.

Yours for great science,

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

Free Glassware from Norm Stanley

Editor,

I have some chemical glassware and metalware that I'll give to any SAS member who will pay shipping cost, or else pick up here in midcoast Maine. Email me for a list of items available.

I also have a few chemicals, but cannot ship those.

Norman F. Stanley

Question About Integrated Circuit Pin Diagram

Editor,

I have four integrated circuits that I cannot find the pin layout for. Could you supply me with the pin layout for the IC 7489 64-bit Ram, explaining what each individual pin does? I would greatly appreciate your help!

Your biggest fan,

Nick

Rather than scan a page from a book, I just entered "7489" in Google Images (go to www.goggle.com and click on the Image option). Here's one site: http://www.physics.mcmaster.ca/phy4d6/Lab/ics/7489.gif I stopped here, but you might want to look elsewhere, also. The main site has pin outlines for all the common logic. Editor.

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