Archive for the “Physics 101” CategoryVia SayUncle Climate Engineering – Because the government is so successful at everything else…Posted on April 9th, 2009 by alan in Obamanation, Physics 101, Weather, genocideIn a stunning example of hubris John Holdren (Obama’s science advisor) thinks he can successfully engineer the Earth’s climate.
Brought to you by the government that has been so successful at managing the economy, it’s budget, the “war” on drugs, etc. The weather, like the economy, is a chaotic system and inherently unmanageable. Attempts to actively manage chaotic systems ALWAYS fail, usually disastrously (See USSR, Mississippi RIver flood control). And the Obama fail train keeps on rolling.
Orin Kerr over at The Volokh Conspiracy found this gem:
X-Rays come from the darnedest placesPosted on October 26th, 2008 by alan in Awesome, Makin' Stuff, Physics 101, RFSo you can make anything – including an X-Ray machine with tape.
It has to be in a vacuum, but still…
Totally cool, and it’s not April 1st, so it might even be true.
Slow News Day at the New York TimesPosted on June 3rd, 2008 by alan in Physics 101, RF, Snark, Stupid MSMIt must be a slow news day because the New York Times has dusted off the bi-monthly cell phone scare story. It’s a pet peeve of mine, so I’m going to rant about it.
Well the first problem is it’s Larry King. The second problem it’s neurosurgeons, a medical specialty prone to knowitallitis. When you’re talking about damage to humans, there are two kinds of Electromagnetic Radiation: Non-Ionizing and Ionizing. The Ionizing type is pretty much everything with a wavelength smaller than the color purple. Ultraviolet, what causes sunburn, is ionizing electromagnetic radiation from the Sun. (Although you can also get UV from a sunlamp, it’s what makes a tanning bed work.) X-rays and gamma rays are also forms of ionizing radiation. It’s called ionizing radiation because the wavelength is so small it can knock electrons off atoms causing damage to the molecules that are part of your body. If you receive enough ionizing radiation the cellular damage can be fatal. Fortunately for us, the chunk of the EM spectrum that cell phones operate in is the non-ionizing part. Non-ionizing EM radiation can also hurt you, but it does it by directly transferring energy, also known as heat. Any radio wavelength can burn you if there’s enough power behind it. That’s how a microwave oven works. The magnetron in a microwave oven puts out 700 to 1500 Watts and the heat cooks the food. But that effect is nothing special to microwaves. ANY RF with that kind of power behind it will burn you. Try touching a 60 Watt light bulb while it’s on sometime. Oops, that hurt didn’t it? That’s the claim about cell phones, that the RF from the phone heats your head and causes long term damage. And it’s total bullshit. The average adult human emits 95 Watts in infrared (the part between microwaves and visible light) all day long. A GSM cell phone emits, at most, two watts. If the fraction of a degree of heating from a cell phone caused damage, how much damage must be caused by touching another human, something 47 times hotter than your cell phone? (I’m not talking about the heat from the battery, that’s much hotter as you know if you’ve ever had cell phone ear from a long conversation.) If heating from cell phone radio waves could cause damage then even standing next to another person would be deadly. That 100 Watt light bulb in the bedside table lamp would be killing you. Even worse, the Sun’s energy is about 1000 Watts per square meter at the Earth’s surface, (Give or take depending on latitude and elevation.) If the heat from a cell phone was dangerous, the Sun would be KILLING you. Clearly we’re not all dead. Feel free to hold your cell phone next to your head. It isn’t dangerous at all, unless you’re driving or next to me in a movie theater.
More Radioactive Stuff Please!Posted on April 11th, 2008 by alan in Guns, Photo, Physics 101, Snark, UncategorizedIf there wasn’t so much PSH over radioactivity we could have atomic batteries in our electronics that last for years instead of chemical batteries that only last a few hours. Irrational fears of radioactivity have kept useful products off the market for too long. Yes, radioactive material can be dangerous, and in the past it’s been misused, mostly due to ignorance. But the benefits, like nuclear power, are too great to ignore in a time of $100+ oil. In the last couple of decades tritium has been used for self illuminating watches and gun sights. I’ve also seen some key chains and exit signs that use tritium. The decay product of tritium is the beta particle which is pretty much the same thing that makes the picture tube in your old TV work. The nice thing about the beta particles emitted from tritium is they won’t go through skin so unless you eat it, or breathe it, tritium is safe. There are chemicals we use every day that will kill you a lot quicker than tritium if you ingest them. In the photo below are a couple of watches with tritium inserts. The one on the left is about two years old. The one on the right is eight years old. You can see that the older one has faded a bit, but it’s still bright enough to see in the dark. Tritium has a half life of about 12 years, which is why the seven year old watch isn’t as bright as the two year old one. The two year old watch gives off enough light to read a book if you hold it close enough to the page (and you let your eyes adjust to the dark). (the pictures are all 15 second exposures in a dark room) Below are the TFOs on my XD .40. The rear sight has two yellow dots and the front is green. It’s a little fuzzy because my camera doesn’t have manual focus. Here are the Trijicon sights on my new XD Sub Compact. They’re green on the front and back. I like the green front sight, but I like the idea of a less bright rear sight because I think it naturally draws the focus to the front sight. I say idea, because I haven’t spent much time shooting either in low light. For some reason ranges don’t like people shooting in the dark. The point of all this is that there is a place for products that use radioactive decay for power. It’s time to get over the fear of radioactivity and realize that properly used, radioactive materials are safe and useful. Besides, it’s cool to have nuclear powered stuff.
The 700 MHz auction won't change your life as much as you wishPosted on February 11th, 2008 by alan in Economics, Physics 101, RF, Snark, WiFi, iPhoneA lot of people are very excited about the current 700 MHz auction. I’ve heard all kinds of nonsense like “nationwide WiFi” tossed about by people who should know better. What are the real possibilities for the current 700 MHz auction and the 12MHz that AT&T recently bought? In the previous 700 MHz auction none of the winners did anything with the spectrum space. To the auction winners it was just an investment that they never intended to use. Last year AT&T purchased 12 MHz of 700 MHz space from previous auction winner Aloha Spectrum Holdings and the FCC approved the purchase last week. (A few years ago I talked to Aloha about leasing some of the space for the company I worked for at the time. I was told by Aloha that they had no intention of doing anything with the space, they were just holding on to it as an investment.) There are several things AT&T can do with it’s shiny new 700 MHz space. They can sit on it.
XD Update – TFOs Are FantasticPosted on February 9th, 2008 by alan in Guns, IDPA, Photo, Physics 101, Snark, What Am I Doing?, politicsI Picked up the XD from the gunsmith Friday afternoon. I put the bore sight on it when I got it home and it looked like it lined up a scooch to the right so I shot the IDPA match this morning with the Para-Ord .45. After the match, I tested the XD on one of the IDPA targets and, sure enough, it was grouping a few inches to the right at 20 yards. I should be able to fix it with the trusty sight alignment tool now that the dreaded XD factory sights are gone. The TFOs are MUCH better than the factory sights. That green front sight draws your eye like a magnet. It’s hard to NOT look at it. They show up good in the dark too. The tritium gives it just enough glow to see without being too bright. (Nuclear powered sights… Makes my inner geek squeal with happy.) I need to find a fiber optic front sight for my Para-Ordinance .45 now. The gunsmith said he wound up having to use a steel punch and a big hammer to get the factory sights out. They were pretty mangled, but I was going to throw them away anyway. So if you have an XD and you want to replace the factory sights, don’t even bother trying it yourself, unless you’re a competent gunsmith and in that case why are you listening to me? UPDATE: Trusty Sight Alignment Tool worked. Bore sight laser is now dead center on the front sight. Of course I’ll have to actually shoot it to make sure, but that’s the fun part. And here’s the picture of XD with TFOs and the Trusty Sight Alignment Tool. You can see the front sight glowing even in the somewhat dim room light. It’s extremely bright in daylight.
In my career I’ve made mistakes and I’ve screwed things up. But I hope I’ve never done anything as monumentally clueless as the following I received in an email from a customer’s “RF Expert”. I’m not disclosing the name or affiliation, it’s just too embarrassing for them.
And yes, he included a helpful diagram: I know, I’m stunned too. It’s amazing. I printed the email and pinned it to the wall so I can look at it when I’m feeling stupid.
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