My Photo


  • Jen-Luc Piquant sez: "They like us! They really like us!"

    "Explains physics to the layperson and specialist alike with abundant historical and cultural references."
    -- Exploratorium ("10 Cool Sites")

    "... polished and humorous..."
    -- Physics World

    "Takes 1 part pop culture, 1 part science, and mixes vigorously with a shakerful of passion."
    -- Typepad (Featured Blog)

    "In this elegantly written blog, stories about science and technology come to life as effortlessly as everyday chatter about politics, celebrities, and vacations."
    -- Fast Company ("The Top 10 Websites You've Never Heard Of")
Blog powered by Typepad
Bookmark and Share

« i think it's time | Main | NEW VOICES: georgie boy »



"That ray is a stream of electrons produced by the heated cathode filament and steered by electromagnetic coils"
- the deflection in a CRT is done electrostatically, via condensor-plates. you have two pairs of plates, one for vertical and one for horizontal deflection. In your basic telly, that's it. No magnets, because electrons follow spiral paths in a magnetic field, and you generally don't want that in your monitor...

"So, those pesky free electrons—how harmful are they? Um, depends on the source."
- actually, it doesn't depend on their source, but on their energy. An electron is an electron, whether it is generated by a hot filament, a cold cathode or something else. How much damage it does to biological tissue depends on how fast it goes. Too slow, and it won't penetrate at all (an electron that is just sitting there won't kill you). As it gets faster, it will penetrate your skin and create all kinds of havoc. Still faster, and it will generate nasty secondary particles and radiation...

Still, a very excellent post - I do hope you'll forward the link to your amulet-bearing friend!

Thanks for this--it answers a bunch of free-floating questions I've had for years.
But last night I watched "The Matrix" for the first time (must be the last person in the Western world who hadn't seen it...) and encountered a whole new question that had never occurred to me: could the energy we humans create really be harnessed, like in the movie? As a science non-starter, I have no idea. (It looked cool, though.)
I imagine there have been zillions of words written on that movie, some of which surely answer this question, but I thought I'd start here, if you'd care to comment?

Thanks for the corrections, Boris. That bit about the source slipped by my editorial eye (which sadly is not so different from my writers eye, when it's my own stuff).

Frescadp, I'd have said the Matrix scenario was speculative at best until I found that article about the power inside our own cells. Now, I'm not so sure. Of course, tapping it is the real problem. Not sure how it could be done without killing the, er, "battery."

Any electrical engineers or biophysicists wanna take a stab at it? Theoretically, of course.

The threat to health from exposure to EM radiation has been hard to fully confirm or refute because the research into this question never seems to go beyond the issues of ionization and/or thermal absorbtion.

What if the threat arises due to the wave mechanical property of entrainment & induction ? What if EM exposure leads to persistent or even intermittent stimulus or damping of our natural biological systems whose natural frequencies fall largely within the range of 0.x to say 50 hertz ? What is being overlooked, I suggest, is that we are constantly being exposed to a barage of signals in this range due to the phenomenon of beat frequency, the difference in frequency of 2 incident waves.

So if i'm simultaneously being exposed to say, a voltage regulated device at 60 Hz and the field from the power line in the wall beside me whose voltage is less regulated and wanders above and below 60 Hz (rms), then I am also being continuously exposed to a wandering range of beat frequencies between 0.x and say 2 Hz which falls into the range which can resonate with and either stimulate or damp and thereby possibly disrupt even robust and redundantly sustained biological systems.

The suggestion is therefore that signal jamming is the unappreciated threat vector we should be testing for in regards to EM exposure.

Why is use of cell phones prohibited in proximity to intensive care unit medical equipment and on aircraft during takeoff and landings landings ? Surely these electronic systems are robust and redundantly sustained.

Well, it's not because we are going to give those devices cancer that cell phone use, in an aboundance of warranted caution, is prohibited. Its because cell transmissions might induce disruption and somehow jam the normal functioning of these systems. It seems to me that biological systems might well be at similar risk of disruption in view of beat wave mechanics.

If patterns of flickering light can set off epileptic seizures, maybe flickering patterns of beat wave exposure are leading to the chronic overstimulation of immune systems that some research into this subject has been talking about not to mention the so called Electromagnetic HyperSensitivity (EHS) syndrome which, according to the Wikipedia page on the subject, is proving difficult to firmly confirm or refute.

An EM threat to health seems to me to be very plausible in a paradigm which properly takes into account the role beat wave exposure might playing.

oops, just realized after the fact that it's the voltage that wanders around 120v rms and not the frequency in my quick example above but the beat wave notion applies nevertheless when exposed to multiple, not exactly same, sources of exposure. ;)

Some nitpicking...

"A radioisotope emits enough EM energy to strip away the normally tightly bound electrons from an atom, making it a charged particle, like x-rays. Only the shortwave end of the EM spectrum has enough energy to do this—not the electrons coming out of your CRT TV. "

I thought CRT's do produce xrays. (both in the production of the free electron, and produced in bremsstrahlung from the electrons as they slow down.) Later in your article you seem to agree that CRT's produce x-rays.

However, this is just nitpicking, I do agree that the xray production are below safe levels.

I'm not really opposed to blunt-force truth if it will save your sanity...I think it depends on the person you're dealing with. If its someone you otherwise dig, and you want to save them the pain of lost money or embarrassment, go with whatever tone you think would get through to them based on past experience. I save friends from Kinoki foot pads just by telling them there's a stinky dye in the pads that make them turn brown, and it will stain their sheets. Works perfectly well every time!

our nifty wave/frequency/energy graphic needs a little tweaking. For example, you list "aircraft band" as being a lower frequency than AM radio. That is true only with regard to ground based non-directional beacons, which are in the 200-400 kiloherz range.VHF (very high frequency) communication radios and VHF navigation radios (VORs and VORTACs are in the FM range, slightly higher than commercial FM radio and TV. And militry aircraft usually communicate in the Ultra High Frequency range at roughly double the VHF frequency.There is also a Very Low Frequency, really long wavelengths (on the order of 1 to 10 kilometers) navigation radios.And to the extent airborne GPS is used, the carrier wave frequency is 1575.42 MHz. And aircraft radar operates in one or more of 7 bands, depending on mission, i.e., wather, ground mapping, attack, etc.Airborne weather radar operates in the microwave band.
At the other end of the graphic, it is my understanding that "cosmic" gamma rays are actually not photon mediated and are really particles, to the extent that the word has any meaning now.

CRT's can potentially emit x-rays. For more information about CRT type televisions and monitors look here: We Want You to Know About Television Radiation ( and Televisions and Video Display Monitors (

The comments to this entry are closed.

Twitter Updates

    follow me on Twitter

    Physics Cocktails

    • Heavy G
      The perfect pick-me-up when gravity gets you down.
      2 oz Tequila
      2 oz Triple sec
      2 oz Rose's sweetened lime juice
      7-Up or Sprite
      Mix tequila, triple sec and lime juice in a shaker and pour into a margarita glass. (Salted rim and ice are optional.) Top off with 7-Up/Sprite and let the weight of the world lift off your shoulders.
    • Listening to the Drums of Feynman
      The perfect nightcap after a long day struggling with QED equations.
      1 oz dark rum
      1/2 oz light rum
      1 oz Tia Maria
      2 oz light cream
      Crushed ice
      1/8 tsp ground nutmeg
      In a shaker half-filled with ice, combine the dark and light rum, Tia Maria, and cream. Shake well. Strain into an old fashioned glass almost filled with crushed ice. Dust with the nutmeg, and serve. Bongos optional.
    • Combustible Edison
      Electrify your friends with amazing pyrotechnics!
      2 oz brandy
      1 oz Campari
      1 oz fresh lemon juice
      Combine Campari and lemon juice in shaker filled with cracked ice. Shake and strain into chilled cocktail glass. Heat brandy in chafing dish, then ignite and pour into glass. Cocktail Go BOOM! Plus, Fire = Pretty!
    • Hiroshima Bomber
      Dr. Strangelove's drink of choice.
      3/4 Triple sec
      1/4 oz Bailey's Irish Cream
      2-3 drops Grenadine
      Fill shot glass 3/4 with Triple Sec. Layer Bailey's on top. Drop Grenadine in center of shot; it should billow up like a mushroom cloud. Remember to "duck and cover."
    • Mad Scientist
      Any mad scientist will tell you that flames make drinking more fun. What good is science if no one gets hurt?
      1 oz Midori melon liqueur
      1-1/2 oz sour mix
      1 splash soda water
      151 proof rum
      Mix melon liqueur, sour mix and soda water with ice in shaker. Shake and strain into martini glass. Top with rum and ignite. Try to take over the world.
    • Laser Beam
      Warning: may result in amplified stimulated emission.
      1 oz Southern Comfort
      1/2 oz Amaretto
      1/2 oz sloe gin
      1/2 oz vodka
      1/2 oz Triple sec
      7 oz orange juice
      Combine all liquor in a full glass of ice. Shake well. Garnish with orange and cherry. Serve to attractive target of choice.
    • Quantum Theory
      Guaranteed to collapse your wave function:
      3/4 oz Rum
      1/2 oz Strega
      1/4 oz Grand Marnier
      2 oz Pineapple juice
      Fill with Sweet and sour
      Pour rum, strega and Grand Marnier into a collins glass. Add pineapple and fill with sweet and sour. Sip until all the day's super-positioned states disappear.
    • The Black Hole
      So called because after one of these, you have already passed the event horizon of inebriation.
      1 oz. Kahlua
      1 oz. vodka
      .5 oz. Cointreau or Triple Sec
      .5 oz. dark rum
      .5 oz. Amaretto
      Pour into an old-fashioned glass over (scant) ice. Stir gently. Watch time slow.