That's all the response needed to this accusation. The Wifi made me do it.

Jeez -I expect that kind of thing from thr FT with their new fangled fancy look but not from such a prestigious rag such as El Reg.

I would like to see the effect of a scientific test - one group in a classroom with wifi on for a week and off for a week, and see how the teacher and pupils responded, then test it with wifi "on" for a week (placebo dummy router and just tell the subjects that wifi is active; a couple of flashing LEDs should do the trick) and see how they respond to that.

On the Independent on Sunday.

So it must be true.

It does show that teachers as a body are no better acquainted with either scientific method or notions of causality than any other sector of the population.

Power lines.... electro-magnetic radiation.... wi-fi????

I'm a little confused. Perhaps I have missed the connection and I lack a general understanding of how wi-fi works... perhaps not?

Can I suggest that the schools investigate the effects of the mobile phone network provider masts, that many now have on the roofs of their school buildings, as a source of additional income?

Many branches of McDonalds have WiFi hotspots in them. Its all so obvious now: that's why children who spend all their time in there are all delinquents.

Of course there are lots of multi megawatt transmitters used for TV and radio. It would be quite cynical to suggest that a "shut down TV transmitters" campaign is not forthcoming because it would be unpopular.

As we all know TV and radio uses nice eco-friendly electromangentic radiation as opposed to the nasty evil polluting stuff used by mobile phones and WiFi.

Either that or the huge numbers of cancer cases caused by TV and radio transmitters have been covered up.

Anyone want to buy a tinfoil hat?

No need for the schools to investigate the effects of mobile phone masts. I've done the maths for them.

The usual limit for the power output of a hand-held radio transmitter is 4 watts; at which power level a typical mobile phone battery would be spent within 1 hour if it were operating continuously. The transmitting aerial is about 0.1m. from the brain when the phone is in use.

The intensity of radio waves decreases with the square of distance from the source (think of the total power as being distributed equally over the surface of a sphere). In which case we have a maximum strength of 4 / (4 * pi * 0.1 * 0.1) = 4 / 0.12566 = 31.83 W/m2.

A mobile phone mast carries at most 100 conversations; and its signal has to travel through whatever the phone's signal has to travel through, so it need transmit no more than 4W to reach any handset that can reach it. We can assume, then, that there is no more than 400 watts of RF power coming from the mast.

If the mast is 10m. above the ground, and someone is standing directly below it, then we have 400W of power, 10m. from the brain. This corresponds to a field strength of 400 / ( 4 * pi * 10 * 10) = 4 / 1256.64 = 0.003183 W/m2.

In other words, a person standing directly at the foot of a ten-metre mobile phone mast carrying 100 calls will receive a signal which is 10 000 times weaker at the brain than they would while using a mobile phone.

No need for the schools to investigate the effects of mobile phone masts. I've done the maths for them. (Twice, and this is the version without the cock-up -- AJS)

The usual limit for the power output of a hand-held radio transmitter is 4 watts; at which power level a typical mobile phone battery would be spent within 1 hour if it were operating continuously. The transmitting aerial is about 0.1m. from the brain when the phone is in use.

The intensity of radio waves decreases with the square of distance from the source (think of the total power as being distributed equally over the surface of a sphere). In which case we have a maximum strength of 4 / (4 * pi * 0.1 * 0.1) = 4 / 0.12566 = 31.83 W/m2.

A mobile phone mast carries at most 100 conversations; and its signal has to travel through whatever the phone's signal has to travel through, so it need transmit no more than 4W to reach any handset that can reach it. We can assume, then, that there is no more than 400 watts of RF power coming from the mast.

If the mast is 10m. above the ground, and someone is standing directly below it, then we have 400W of power, 10m. from the brain. This corresponds to a field strength of 400 / ( 4 * pi * 10 * 10) = 400 / 1256.64 = 0.3183 W/m2.

In other words, a person standing directly at the foot of a ten-metre mobile phone mast carrying 100 calls will receive a signal which is 100 times weaker at the brain than they would while using a mobile phone.

Another excuse to get out of doing your homework.

... I work in a school and the kids behave awfully. However we do NOT have a campus wide wifi network (we have a few access points in the IT department).

You can blame their behaviour on the fact that no-one can discipline them any more without getting locked up... parents and teachers... detention these days is 30 minutes in which the kids do their homework! Also they get mobiles when they are as young as 7

the mobile mast ten meters above ground will radiate outwards to the sides very little signal getting straight so devide your figure by 30db 3db 1/2s the signal 8out of ten for effort

I presume that the wifi in the schools must be very different from the wifi in the offices which have had no noticeable effects on office workers, overall.

Can they suggest a mechanism for how the radiation affects the children? Can they suggest how such low doses of radiation can affect kids but the much higher doses from talking constantly on their mobile phones doesn't affect the children? Have they an idea of numbers - is it one in 10 children affected? 1 in 100? 1 in 1,000? Or rarer? What happens if the radiation source ceases, does behaviour improve (this is known as dechallenge and in pharmacovigilance is a strong marker for causality)? What about if the radiation starts again, does the behaviour then deteriorate?

Or are we, as usual, dealing with a bunch of pseudo-scientific claptrap from people who really ought to know better. If so I know a hippy guy who sells crystals that can really help with this radiation stuff...

The common thread is that radiated energy from power lines, wi-fi, and cell phones is invisible and imperceptible. It's like the proverbial weapons of mass destruction; convenient to explain whatever you want explained.

That may include why you find the students this year so much less respectful than the ones you faced just 20 short years ago when you were idealistic, young, and energetic. If you also don't understand wi-fi nearly as well as your class does, and don't want to take the time to learn it, then it's clearly the culprit.

Nobody wants to turn off the electricity. But it's no surprise that nobody wants to live underneath a big ugly high voltage line. Nobody wants to turn off their TV, but who wants to live under a big ugly transmitter tower. Scary invisible death rays are a stalking horse for whatever is really the issue.

Maybe somebody should ask the teachers why wi-fi was added in the first place, and whether that turned out to be a good idea or not. And maybe ask why they want rid of the thing so much. It's not death rays, that's for sure.

Husband: Ready for bed (wink, wink)?

Wife: Not tonight, dear. The wi-fi has given me a headache.

You can probably get more radiation from sitting in front of a monitor. I would like to see a test on this. Maybe it has something to do with honey bees disappearing.

To perform a test like this you might have to turn all the Cell Phones off first. Cell phones may be as likely or more likely a culprit as wireless.

I recall seeing this on telly some time ago - I may have the details wrong, but it was generally like this. It was only a very small test (6 subjects IIRC) but the results were interesting. The subject were put in a house and an antenna was put outside and the subjects told that it wasn't switched on. After a couple of days, they were told that it was switched on - but it wasn't.

Once the subjects believed the transmitter was on then several of them developed the sort of symptoms described and had to leave !

Seriously folks, I think the main point of the article is that while we seem to be blaming kids for their behavior these days, it is retarded teachers that are the problem.

I heard about this yesterday on a school computer IT mailing list (in Australia).

When you consider that the US FDA consider 5mW of 2.4GHz at 2 inches to be perfectly safe, the 20-100mW put out by wifi access points is pretty safe. Unless you regularly partake in activities such as wearing access points as hats, or inserting the antenna into body cavities, I think you'll be fine.

A member on the mailing list I heard it from took a microwave leak detector device and held it to the antenna of an access point. It didn't even register anything. Meanwhile, a microwave oven triggered it to display a "safe" level of radiation.

I think it's time for an investigation into the health effects of radar speed guns - on their users, naturally. Seriously, though, if EMR is such a threat, shouldn't all radio transmission be banned? Mind you, some of the content broadcast today seems to be much more damaging to the brain than any effect caused by the carrier wave.

Shut down all TV transmitter towers by all means !! I only watch Cable TV anyway !! And as for mobile phones, bring back the string and two baked beans cans !!

With teachers of such a calibre, can we wonder at the kids' exam results ???

the combined power of many devices should be added together. The problem is that one hotspot is safe, but if you have a house where there a hotspot in every flat (due to the local telco using wifi routers by default) this can add up to a nice level of power (and a low shared bandwidth).

Someone has mentioned if a mobile phone would be transmitting continously then its battery will be empty after an hour. This is exactly what happened a few days ago during a wifi phone test. The jurnalist was suprised when he turned on the wifi in his nokia to use voip, the phone battery was empty after an hour, even thogh he only talked a few minutes. (wifi doesn't have much power control in the standard)

There is also a problem with the frequency of the waves. Microwave ovens use 2.45 Ghz so they can heat up bipolar molecues better. Using 900 Mhz would be less effective. The trouble is that wifi uses 2.40 Ghz. If they used 900 Mhz or 850 Mhz they would be less effective. If they used 50 Mhz, even less. But they couldn't because 2.40 Ghz was a free and fast band. It was free because it's polluted by microwave ovens and it's fast because the frequency is high.

It's a well known fact that 50/60 Hz power line frequencies can disrupt the sleeping patterns of humans if the power line goes near enough to their head. We are just making it worse by using higher and more dangerous frequencies. (they are not lethal, just disrupt our neural system which is a chemoelectric system running around 1 volt and a few kilohertz) Wifi is not a death ray, just a source of electromagnetic noise that is as damaging to the human thinking process as a loudspeaker emitting audible noise.

Cordless baby alarms transmit at the same frequencies and strengths (as do DECT phones). Parents stick these next to sleeping babies' heads. I would suggest that campaigners should start off there....

It's pretty amazing that wifi works at all....

.... well just a few anyway.

Retarded teachers, retarded children, we're all screwed and this society is going down the pan faster than the aftereffects of a vindaloo kebab bought from the van outside the pub the night before.

I used to teach but quit cause teachers moan too much about nothing.

Stop the little sods from consuming sugary drinks, and watch their behavior calm down..!!

Ok, I actually don't. Anyway, perhaps they would have more creditability if they considered changing the name of their union... National Union of Teachers (NUT). It makes it much easier to write them off as just a bunch of NUTs.

No jokes here, so don't read on if you can't do serious.

There is no doubt in my mind that wi - fi could cause health problems. For a variety of reasons a minority will be more sensitive as is the case with OCD, depression etc.

And remember all new illnesses go unrecognised until the evidence can no longer be ignored - gulf war syndrome, allergies, anorexia to list a few. This looks like another one.

It would be wrong to continue with wi-fi in schools if there is any doubt about its safety especially when there is such a simple alternative.

Our childrens health deserves our full consideration - nothing less!

Don the tin-foil hats!

It is our only hope...

if fokes are that worried about kids health, stop them playing or watching tv/computer games in bedrooms all night... get them to run about outside in the fresh air ... in fact why do perents spent time with kids??, instead of dumping them in front of the tv, or out on the street with nothing better to do than chav about...

wi fi has been about for years.... when i started in my secondary we allready had wifi nokia network coving the site... theres your long term study... as i have been working here for nearly 8 years, ps we are in the top 10 % of the counries gov run schools.

its more likely teachers issues are not linked to wifi but not sitting correctly in front of laptops or staying up till silly 0'clock planning, marking, and stressing about teaching the next day... not to mention the amount of silly forms, risk assessments, trip letters, internal staff issues, and sickness cover...

/rant