Re: Wireless Power Nearly There

It goes to show you how little the average person/journalist knows about technology. Seems they forgot everything they were supposed to have learned in high-school physics class... and I'd say freshman physics in college too, but perhaps J-school students don't have to take that. These days they probably should...!

"Joel Koltner" wrote in news:x7Csk.56813$ snipped-for-privacy@en-nntp-03.dc.easynews.com:

Even if they take the class, the other question is, do the state employees know how to teach it...?

Meanwhile, of possible interest:

Of course, that means that up to 60% of students don't take physics.

This is from 2003, but FWIW:

Also, students not only graduate with little to no science background, but, for example,

And that's *college* graduates - so, if 30-some percent of high school gradiates attend college, and only 31% of those can comprehend a reasonably-complex text, what does that mean for the up to 60% who never attend college...?

Too many people are going to college. It wastes resources and is a disservice to the many people whose minds just don't work that way. They can't do it, drop out, and feel like failures. The idea of preparing everyone for college is silly, and destructive. Serious, professional, and honored vocational education should be available to everyone by choice, even the college dropouts.

California now wants to force all 8th graders to take Algebra.

Just read this nonsense:

"At the risk of perpetuating the stereotype of librarians ... I'd be glad to state, on the record, that algebra is uniquely useless in life, and that the only good number is a call number." Nadine Walas,

John

arned

oo,

Hate to point this out, but today people worry about the minute amount of radiated energy emitted by cell phones, so just imagine how they would feel about an electromagnetic wave radiation source in their home that emiltted not milliwatts, but tens or hundreds of watts.

Then too, don't forget that the inverse-square law applied to all electromagnetic radiation, not just light. Tesla never appeared to understand this, either because while a great engineer but ignorant about basic physics. Then too, there is another explanation about Tesla's problems, which most readers know about.

Don't know about other readers, but when I was around 13 years old (and held a ham radio operators license), I once rigged up my 60-watt

Actually, many home appliances are already being charged by the use of electrogmagnetic fields, cordless toothbrushes for one simple example. Most readers likely own one of these and are well aware of the limited charger range.

Now here is something hopely informative to non physics students, at least if you accept the intitial demonstrated premise as fact. Here is that premise: All electromagnetic radiatin is emitted in the form of spherical wavefronts, which propogate as ever expanding spherical surfaces, Consequently, the energy density they contain is is inversely equivalent to their ever increasing spatial volume. Now apply the math taught in middle school, and think about how much energy is intercepted by an antenna or other receptor sitting on the surface of that expanding sphere of ever decreasing energy density. If you managed to hack though my imperfect explanation, you know what learned why radiated electromagnetic energy is alway inversely proportional to its distance from the radiation source. If you didn't understand this previously, chances are that you do now.

Usually, the following question is what happens if I were to focus the beam though use of a lens, reflector, or laser. Not wishing to hog the spotlight, since I am merely a BS/MS guy, I'll leave it to someone else here to explain this to you, since it deals with issues and devices that would take many word to explain. I'll leave it simply by saying that these devices make the apprarent distance of the radiation source different, but the inverse-square law still applies.

Fun stuff.

Harry C.

arned

oo,

Joel, your point is duly noted, and entirely correct.

I don't wear a 'Brass Rat' on my finger, lets simply say I am very close to MIT and it's students.

Let me simply say that other than possibly Cal Tech, I know of no university on Earth that puts its engineering and their hard-science students under more pressure than does MIT. Hell, I am hard pressed to believe that this place is even part of the US and not China or Japan. The toughest credentials in the US to earn are an MIT righg (the legendary Brass Rat), or to complete USMC or USN SEAL training (I believe that you are awarded a ring for this too.)

Now becore you put down the undergraduate students at MIT, realize that many are among the brightest and arguably the most misguided kids that our country has to offer. They actually celebrate the mid- semester flunking out of their classmates with a party. Realize, here we're addressing the Nerdiest of the Nerds. Still, it has to be said that I've never heard on one of thise kids doing anything really destructive, not that they couldn't. Still most MIT students are so intelligent that they wouldn't take the risk.

So, to let off steam they have the 'MIT Model Railroad Club', and club member are behind most of the pranks anually played, which range from putting a VW and later a Police Car on top of the 'Dome'. Today the pranks are much more tame and less imaginary, like deceiving the press with silly public statements, or reprogamming variable message public signs with silly messages. In the Boston areas, we all (including the police) take these pranks with a grain of salt, becasue none of them really hurt anyone.

Now, on the other hand, most upperclassman at MIT have served their time in industry, and are quite familiar with the telephone systems, traffic control systems, and power grids through out the Northest, and trust me that if any of these kids had a particularly evil intent, I have little doubt that all of these infrastrure components could be shut down in a matter of a few moments. Still, that not the nature of an MIT student prank.

Still, over the years, the need to let off midterm steam by MIT students has diminished in both amplitude and creativity. Now, devil that I am, I might just target the clock on top of the Customs Tower. I'd first try to make it run backwards, and then at night flash in the backlight MIT in Morse code.

I might be also inspired to reprogram the message on the Ted William Tunnel with a sign "No Cars or Taxis Allowed".

Harry C,

Actually Tesla was not ignorant of basic physics, either electrical or otherwise. Unlike Edison who was basically a garage trial and error man whose main contribution was the invention of the industrial research laboratory (with the taking credit of the work of all your employees). Tesla had a real European education. Did you invent the automobile speedometer? Yeah, I didn't think so. Do you even understand the physical principles that make it work? Basic physics at its finest!

The only problem here is that the inverse-square law does NOT apply to electromagnetic induction! In fact if you have a "long" solenoid, the induced voltage in a loop around it does not diminish no matter HOW large you make the loop! Proof of my statements is left as an exercise for the interested student.

Hence, there certainly are real advantages to using induction rather than radiation to transmit energy. Still, these are not "new" ideas!

My favorite tech school prank (another school, not MIT) was making a dorm room "disappear". It all started when someone discovered that the workmen who painted the dorm had left several cans of the paint in the dorm basement. A prank HAD to be invented for it! The plan became to make the room of a certain especially "nerdy" student "disappear" over spring break. The time comes and a special frame was engineered to fit the guy's door that was diligently plastered seamlessly into the wall. The whole thing was sanded smooth and the basement paint perfectly applied to match the hallway dark green bottom, light green top and mid green stripe between the two.

It was hilarious. The guy comes back from break and "poof" his room is GONE! Had him going for quite a bit. But you know nerds are pretty smart. Eventually he went outside and counted the windows and figured out the prank!

They just don't make students like they used to!

Do you really think that having to go outside to count windows was 'smart'? He should have been able to see the odd spacing, and use his knuckles to locate the covered up doorway. The floor should have had some wear marks as well, unless it was a brand new building. Lots of signs point out the location in a prank like this. Was there a baseboard? If so. it had to be spliced. If there wasn't, there would be wear marks near the bottom of the wall that would be a dead giveaway, unless he was completely blind. Hell, I have found plastered over outlet boxes in new buildings with a couple taps, and I didn't need four years of college to find them. If this is your idea of creativity and intelligence, it's very disappointing.

So basic I figured it out at 10 years old, by examining a speedometer and odometer from a junk car. BTW, the odometer was more interesting than the simple magnetically couple meter movement. The magnets weren't coupled tight enough to lock, but the faster the cable turned the input magnet, the more it pulled the secondary magnets against the hairsprings. A couple magnets, and some clock parts. Big deal. The odometer was more complex, with the reduction gears to reduce the number of turns from 1001 to 1, and the pawl driven drums to index the next drum.

That's too old.

She should be fired and given a pitchfork to clean out stalls. After two years of that kind of work, maybe the farmer would show her how s/he uses algebra.

The goal of EEO is to dumb down everybody.

/BAH

Perhaps not but his new-age worshipers are.

/BAH

I've been harping on just that here in Arizona for years... to no avail. Of course I've also been harping on the quality of teaching as well. Thus I'm under constant attack by the teachers' unions.

The quality of students has been dropping steadily. So I finally retired from interviewing students for admission to MIT. I just couldn't cope with enthusing students when I knew they were losers :-(

...Jim Thompson

Algebra ahould be an elective, for kids with the interest and talent. Expose everybody to a little of it and see if it clicks for them.

Some people don't, and never will, get symbolic math. They likely have other skills. Teach them basic, intuitive arithmetic skills and let them be good at whatever they can.

I can't remember the last time I solved a quadratic. It's surprising how much you can get done by numerical (non-symbolic) futzing.

John

For the sake of Mr. Rattner's data, I hope his laptop has a solid- state hard drive...

Michael

Algebra is more than solving quadratic equations.

You are using basic algebra every time you go to the supermarket and compare the value of buying 4 6-packs versus the 24 pack.

I would agree that anything beyond the basics for ALL people is probably a waste.

No; there's no symbolic math. I can intuitively multiply by 4, or read the price per ounce off the tag. Most people understand that. That's simple arithmetic, but doesn't use an expression in "X". The claim that all basic math is "algebra" is silly.

What symbolic expression *would* you use to compare those beer prices?

Perple are very different and have various talents. I have no aptitude at all for music or languages, and was forced to study both. Everybody should be exposed to choices, and then allowed to do what they have talent for. I don't think we'd get any fewer good engineers and scientists if we let kids learn that way; maybe more.

Fewer and better math students taught by fewer and better math teachers might have better outcomes. It would sure make the players happier.

John

Wow, I wouldn't have guessed it was so high!

Yeah, this number I'm more familiar with, but it's still scary -- and was also unexpected when I first saw it. Maybe I just didn't notice, but in years past I would have swon than my high school had at least a 95% graduation rate.

Indeed. Seen on a 4H club exhibition yesterday (displays by kids in various hobbies, this one in target practice): "49% of house's in the US have a firearm."

There's a bunch of college branks in this book:

The covers shows a bunch of those horribly tacky pink plastic flamingos on Bascom Hill, at the University of Wisconsin where I was an undergraduate... although the only class I took in the fancy Bascom Hall shown in the background was Calculus II... from one Dick Askey

Ha! I just checked on ratemyprofessors.com

I wouldn't be surprised if he and Jim would get along swimmingly. :-)

---Joel

A bad choice of example on my part and not all stores have unit pricing on all things.

total cost = cost per unit * quantity

Basic algebra starts out with A = X * B solve for X and goes on from there.

Basic algebra is establishing the relationship of things.

And there is more to life than shopping for beer.

FWIW, the next door neighbor is a welder. One day I see him solving a bunch of equations so I ask what he is doing. Figuring out how long a piece of steel needs to be to build the thing he is building is his answer.

It turns out one of the reasons he's the foreman is because he can do the simple algebra and trig required to build structures.

Lots of non-technical jobs make frequent use of basic algebra and trig.

Granted few use anything higher than first order equations, ergo the comment that anything beyond the basics for everyone in probably a wasted effort, but the fact remains that the basics are used by people like welders and carpenters.