Episode 5 Bang Goes the Theory

Hello and welcome to Bang Goes The Theory.

Nowadays we live in a life full of gadgets.

Mobile phones, tablet computers and microwave ovens.

We have all heard horror stories over the years about using mobiles

being bad for us and scrambling our brains.

Or how a wireless device next to your child's cot might put them in danger.

Tonight we look at all the science behind wireless technology.

Later, Howard Stableford updates a story

he first reported 20 years ago

about the dangers of wireless signals.

This little sticker has oscillating quartz crystals.

Put it on your tablet and it protects you from radiation.

And this one is interesting.

This mesh is silver-coated

and protects you from radio waves wherever you are.

Liz discovers that despite being widely seen as a health risk

mobile phone signals can be used to save lives.

What are the advantages of this as opposed to your regular X-ray scans?

X-ray is not very good at detecting tumours in young women.

And I am in the US to reveal how we might eventually be able

to transmit not only information

but also power to our gadgets.

So this is the infrared equivalent of a solar panel.

Correct.

We can take that voltage and apply it to power our transistor radio.

Nice.

That is quite astonishing.

It is hard to imagine life without wireless signals.

But it is easy to forget that for our mobile phones, computers,

televisions and wireless gadgets to work

we all have to live in a soup of invisible radiation.

Because seeing is believing, we have assembled these little gizmos.

-Dallas, grab yourself that.

-Thank you very much indeed.

That detects mobile phone signals.

The stronger the signal the more lights light up.

It is a strong signal. Liz, you take this. Same deal as Dallas.

Why is mine not as big as Dallas's?

Yours is designed to pick up wi-fi signals.

-The stronger the signal, again, the more lights you get.

-Got you.

And mine picks up invisible radio waves.

We will walk around the space and with a bit of camera magic

we can reveal the invisible world of wireless waves.

-Ready?

-Go.

This estate looks pretty quiet but the air waves are teeming.

It is just that up until now you could not see them.

But with our cameras you can. Look at this.

These are radio waves in the red.

This maps out the strength of one particular station.

Mobile phones, shown in green. Fairly consistent signals.

And look at the new kid on the block, wi-fi, coloured purple.

Everyone's got a wi-fi network these days.

There is a peak as I walk past each house.

But, for all the brilliant things wireless does for us,

many of the waves connecting us and our gadgets are microwaves.

That has caused lots of people to worry

about how safe these devices really are.

Which is not surprising. Let me show you why.

Watch this. I will give my wi-fi box a bit of a job to do

by streaming a high-definition video to this computer.

The wireless router is sending the video to my computer

using tiny microwave signals.

Then I am going to warm up my cup of tea.

Houston, we have a problem.

All microwave ovens leak a few microwaves

and if that is close to your computer

they can interfere with the microwaves from the wi-fi.

Interference that can cause a video screen to stop.

But switch off the microwave and we are cleared for take-off again.

You can see the computer picking up loads of information

from the microwave signals coming out of the wi-fi unit.

But when the signals from the microwave oven

start interfering with it, it drops off a cliff and then -

ping - my cup of tea is finished,

right back up, it is working up a treat.

The reason is because those microwaves

and the microwaves from the wi-fi box are exactly the same.

Radio waves, microwaves, light waves,

all types of electromagnetic radiation.

But depending on their frequency, where they come in the spectrum,

they behave very differently.

Light waves show the world around us. Microwaves boil water.

So how come if there is all this

microwave wireless energy buzzing around

none of us are cooking?

Well, what is going on in there is about 4,000 times more powerful

than what you have in your wi-fi router.

Because they're doing different jobs.

This is trying to produce a manifest physical change

on the food and drink inside

but the wi-fi router is just trying to send a signal.

The difference between waving at somebody and walking over

and punching them in the face.

But despite the reassurance the idea of being bathed in microwaves

has never been popular,

as Howard Stableford first reported 26 years ago.

Overhead power lines, radio transmitters and radars,

even everyday visual display units,

they're all sources of a form of radiation.

Since 1986, when we recorded that item for Tomorrow's World,

the apparent dangers of gadgets using microwave signals

have been widely debated.

A quick search produces dozens of websites listing terrible symptoms.

All caused, people say, by phones and wi-fi.

In fact the fear of microwaves is now so strong

that you can buy all sorts of protective devices.

This is interesting. A spray, called electro-smog protection.

Just squirt it on like that. It does not smell very good though.

This is a little sticker of oscillating quartz crystals.

NASA technology.

You put that on your tablet and it protects you from radiation.

Similar idea with this band.

And this one is interesting,

this silver-coated mesh protects you from radio waves wherever you are.

None of these gadgets convincingly explain

how they are supposed to protect us, but they do sell.

So plenty of people must have genuine concerns

about how safe wireless is.

Back in 1986 evidence for ill health was purely anecdotal

but of course things have moved on.

Now we have the results of carefully controlled experiments

that can explain at least some of the illnesses associated with microwaves.

We took a group of 60 individuals and brought them into our laboratory

and asked them to wear a specially designed headset with a device

that looks very much like a mobile phone strapped to the side.

We exposed them to two things.

Either a real digital mobile phone signal or a sham condition.

So the equipment would still beep, and heat up with the red lights

coming on it, but it did not emit anything out of the aerial.

And importantly we did not tell the participants which was which.

The results showed conclusively

that, although they did experience symptoms

in the experiment, they were getting headaches,

they were just as likely to get them in the sham condition

as in the real condition.

So if these symptoms aren't due to electromagnetic fields,

what are they due to?

-Because these people really are ill, aren't they?

-Absolutely.

So we think people who think mobile phone signals

or other electromagnetic fields are harmful,

when they believe they've been exposed to them, it's that belief

that can trigger their symptoms, rather than the actual exposure.

You'd think that James's study and others like it

would reassure people who worry about the apparent dangers of microwaves.

But they don't.

This is Barnoldswick, a peaceful market town in Lancashire.

Back in April 2009, the local council here decided it would be a good idea

to put up a wi-fi network in the town centre,

the first town in the North of England to do so,

allowing local businesses and people fast, free access to the internet

and bringing Barnoldswick speeding into the 21st century.

The plan would have made Barnoldswick among the first towns in Britain

to have such an extensive public wi-fi network.

But people weren't happy.

Existing broadband speeds here

are pretty useless, and we wanted to give people the opportunity

to access much better connection to the internet.

Unfortunately, we had a lot of objections from people

who were concerned about the health risks of wi-fi.

Even after 26 years of research, there is still no medical way

to explain how microwaves could cause cancer.

But just a few studies have reported links,

so there are people who won't rule out the possibility

of new medical explanations.

And despite a complete lack of proven cancer cases, the debate continues.

Now, I looked at similar issues to these in 1986, and then,

I pretty much would have guaranteed that by now,

26 years later, we would have definitive answers.

Why haven't we?

For a very long-term disease,

one that maybe takes ten years or more to develop,

obviously you can't know till that period has elapsed.

We have data at the moment up to 10 to 15 years, but beyond that,

we can't know,

because people haven't been using phones for long enough.

There's a very important study called Cosmos

that the UK's taking part in,

which is trying to do a much better assessment

than was done in previous studies.

It's doing that by following people forward in time,

but we can't know the answer until the study's run its course.

LIZ@ While we'll have to wait a while

for proof that wireless is completely safe,

the technology is marching onwards,

turning up in some very unexpected places.

Microwaves, radio waves, wi-fi - they're all things that make us think

about the technology we use every day,

everything from mobile phones to the internet.

But they're also connected to landmines and cancer,

and I'm going to meet a man who's going to explain why.

Landmines injure or kill over 4,000 people a year

in over 70 countries but, despite heroic efforts,

finding mines in active and former war zones

has become much more difficult in recent years

as munitions technology has advanced.

Ten years ago, the military came to Professor Ian Craddock,

an electrical engineer at Bristol University.

They asked him for help with this problem.

Ian, when you were working with the Ministry of Defence,

-what was the challenge?

-They were interested in the problem

of detecting small plastic anti-personnel landmines

buried in the ground.

How did you go about solving that problem?

You can't find these landmines with a metal detector,

because there's almost no metal content in a small mine nowadays.

So we have to choose part of the electromagnetic spectrum

which is able to penetrate into the ground.

It's a bit like the visible light spectrum

we see in this stained-glass window.

Some panes of glass are transparent to blue light.

Some panes of glass are transparent to red light, but it turns out

that the soil is reasonably transparent

to the microwave part of the spectrum

that we're more familiar with with the uses of wireless technology.

Microwaves can travel through the ground in the same way

that light can pass through glass.

But look at this.

Even though glass and water are both transparent,

we can see the glass beads

in this water, and that's because light moves slower

in glass than it does in water.

Because of this contrast,

we can tell the difference between the two.

It's the same with the plastic landmines.

Microwaves travel through and bounce off plastic differently

than they do in earth,

and so microwave receivers can see the buried mine.

This discovery helped Ian

to design a new type of microwave-based landmine detector,

but it also took his career

down a different, but equally life-saving path.

This is a system for detecting breast cancer.

This is the imaging head, so we've got a cup containing antennas,

-similar to the antennas you'd find in your mobile phone.

-OK.

This is an early prototype, easier to see here.

So the woman will lie with her breast inside the cup,

and then reflections generated from tumours

come back into the ray of antennas.

So basically looking at a difference

in the properties of normal breast tissue and tumour tissue?

Yeah. And we use software to process those signals

and get a 3-D picture of the interior of the woman's breast.

-So that red mass there...

-That was a tumour inside this woman's breast.

What are the advantages of using this

as opposed to your regular scans that you get using X-rays?

An X-ray is not very good at detecting tumours in young women.

So why is it that microwaves show up that contrast better than X-rays?

There's more contrast between the tissues at those frequencies.

The contrast between different materials is not the same

at one end of the electromagnetic spectrum as it is at the other.

So while X-rays are great for looking at bones

hidden under skin, microwaves are better

for spotting the difference between tumours and normal breast tissue.

And, as one in every five women diagnosed with breast cancer

is under 50,

Ian's device could help save thousands more lives.

How close are we to being able to use this on a mass scale?

This is certainly many years away from large-scale deployment,

but it has already been used on cancer patients in Bristol.

So we're surrounded by all this incredible wireless technology.

It's safe.

But the one thing we haven't got sorted yet is wireless power.

You still have to plug something in.

-Are we ever going to get that sorted?

-Maybe.

You can see the appeal. Wireless has given us

countless devices that are free from cables supplying their information.

And yet we still need plugs and wires to power them.

If we could find a way to do that wirelessly too,

we'd never need sockets, power leads or batteries ever again.

Everything would simply work. Like these bulbs.

These bulbs really do have absolutely no wires connected to them.

So why don't we have a system like this at home

in all our living rooms?

Well, that's because it's also extremely dangerous.

The only reason that this works as well as it does

is because I've got a metal plate above my head.

It's set at a few hundred thousand volts.

And when you get massive voltages like that,

they have quite a large field of influence, large enough in this case

to excite the atoms within these tubes sufficiently

that they cause the whole tube to glow.

And in order to produce that huge electric field,

I've had to connect my plate via that copper pipe

to a strange-looking contraption over here.

This is a Tesla coil.

It's our version of something that was invented over 100 years ago

by the visionary but slightly mad genius, Nikola Tesla.

These things are capable of generating hundreds of thousands,

if not millions of volts.

And Tesla built huge versions,

with the intention of transmitting power wirelessly

over vast distances.

The trouble is that the voltages are so huge that Tesla coils,

even small ones like this, can also produce lightning,

which is why traditionally

we've kept our electricity safely trapped in insulated wires.

Wires are incredibly good at transporting electrical power.

There's precious little power loss between where it's generated

and where you're plugging in the device you're using.

But we're inherently lazy,

and we'd really rather not go to the trouble

of having to plug everything in.

So is there a way of having useful wireless power

without having to resort to massive, fatal voltages?

Yes, there is.

Electric toothbrushes and, more recently,

mobile phone charging mats

certainly manage a little bit of wireless power transfer

without the massive voltages.

How do they do it? They do it with magnetism. It works like this.

What I've got here is a coil.

If you put an electric current through a coil,

it becomes an electromagnet.

Switch the current off, and it's no longer an electromagnet.

Now, if you were to put

another coil of wire within that field of magnetism,

you can actually turn that magnetism back into electricity.

And, strangely enough,

you do that by varying that magnetic field as much as possible,

which you can do by simply switching it on and off.

Pleased as I may be with my little piece of wireless power transfer,

it is still a bit weedy and hardly life-changing.

Unlike this.

Now, we're just using a lamp lightbulb at the moment.

But you could genuinely run a telly a couple of feet from a wall

using something very similar. So what's different?

See, whereas I was switching that on and off

maybe once or twice a second at best,

the electronics here switch on and off a million times a second.

And the faster you switch it, the greater its area of influence.

But even with all that super-fast switching,

it's still limited to, well, a couple of feet.

That's because magnetic fields

drop off quite dramatically with distance.

So, how would you go about getting wireless power transfer over huge distances,

something really worthwhile?

For inspiration, you could look to the sky,

because here on Earth, we get almost all our power

from a massive, glowing orb about 93 million miles away.

And there are no wires between the Earth and the sun.

We get all our power wirelessly.

So maybe the answer to long-distance wireless power is light.

I'm going to leave you with that thought for a while,

but we will return to it at the end of the programme.

Dallas, I think you'll find the solution is impressively space-age.

-It had better go further than a metre.

-It will.

OK, it's time for your weekly dose of my favourite wireless gadget,

Dr Yan Wong.

Mobile phones are relatively new,

but would you believe the first wireless telephone was invented

more than 130 years ago?

The sound was carried on nothing more than a beam of sunlight.

Can you figure out how they did it?

The answer to that, of course, is on the website.

And whilst you're there,

you can also get yourself one of these posters.

It features many of the things from this series and shows

how batteries, power cables,

microwaves and hearing aids are all connected.

You can get your free copy by ringing:

Or by following the links

from bbc.co.uk/bang to the Open University.

Also, check us out live.

We're still on tour with the Bang roadshow.

Next stops, Sheffield and Poole. We'd love to see you.

For details, go to:

Right. Back to my quest for wireless power,

and the dream of consigning cables and batteries to history.

Sound like a pipe dream?

Well, remember, we get plenty of energy from the sun every day,

with no wires at all.

We routinely turn light into electricity using solar panels.

But solar panels don't just work off sunshine,

they work pretty well off artificial light too.

The problem is,

the further I move my torch away from my solar panel,

the more spread out the beams become and the less power I can collect.

For this to work over a long distance,

you need a light source that barely spreads out at all,

something like a laser.

With a laser beam,

the intensity of its power remains almost exactly the same

however far along the beam you go,

just like electrical power in a cable.

With all the power of the laser

staying in such a concentrated beam,

the intensity of the light can be extremely dangerous.

But I've heard about a system that gets around this problem,

making it safe to transfer power from one place to another

with no wires in between. I've come all the way

to the United States to see it.

Laser expert Robert Windsor has been setting it up to show me.

At the moment, that's just a normal red laser pointer

he's using to line the system up.

The working laser is far more powerful.

This particular fibre feed here delivers

approximately 20,000 times the power of a typical laser pointer.

'And it gets worse than that. It's an invisible laser beam.

'It uses infrared light that we can't see,

'but which carries a huge amount of energy.'

Look, straight away!

-That's astonishing. That's like something out of James Bond.

-Yeah.

Right, I'm utterly convinced that you've got a very powerful laser.

'As impressive as this display is,

'the dream of wireless power is looking like a choice

'between being electrocuted by the Tesla coil or being burnt alive.

'But Robert's system has a safety feature.'

That's the part where the optics come in

to expand the beam into a safer, larger diameter where,

if you get into the beam, you won't get harmed by that.

'With a special card, I can make the invisible beam visible.'

-It's really warm.

-It can surprise you at times.

-Oh, my life.

-So, can we go and see where it's hitting at the far end?

-Sure.

The receiving end is a quarter of a kilometre away,

on the other side of the campus.

But the laser beam is as powerful here as it was when it left.

-And this is what collects that fat, infrared beam?

-Yes.

-So it's the infrared equivalent of a solar panel.

-Correct.

And then we can take that voltage and apply it to power up an LED.

-Or, we've also got a transistor radio here.

-Oh, nice!

And how efficiently does that then convert the power in the beam

back to electricity?

We're probably really converting maybe 10-15% of it into useful energy

-to drive the LED or the radio.

-I love how it goes in and out.

'And although my hand can block the beam,

'this does seem to be a remarkably practical system

'for long-distance wireless power. It even works in the rain.'

A little bit of rain really doesn't hurt it all that much.

In fact, sometimes I've had trouble noticing any difference at all.

But is it genuinely, like, throughout the whole range,

wherever it goes, perfectly OK to not blind anybody?

With this wavelength and this kind of energy density,

you could put your face into it. It's totally safe.

Getting a normal laser beam in your eye can blind you instantly.

Never, ever look down one. But Robert is a safety specialist.

Everything else I know about lasers says this wouldn't be a good idea.

Under his guidance, I'm about to demonstrate

what makes his system different from almost every other in the world.

Oh, you can really feel the warmth there.

'All the power of that laser, safely spread out

'and at a wavelength that won't even damage my eyes. I'm convinced.

'It is possible to beam power to our gadgets

'without any wires, safely and over enormous differences.

'In fact, huge distances are just what it lends itself to.'

In fact, what really got this whole thing rolling

was the NASA Centennial Challenge, which was a space elevator project,

if you will, beaming power

to a vehicle that could climb a tether all the way into space.

Not only could we beam power up to space, but also back down.

Some groups are looking at putting lasers like these onto satellites

to beam power from their efficient solar panels

to anywhere on Earth, through the atmosphere and at any time,

day or night.

Now, it may never be

the cheapest or most efficient electricity available.

But imagine.

You're in the middle of the Antarctic,

a thousand miles from the nearest plug socket.

I think you'd be very grateful for any power you can lay your hands on.

That's a really interesting film.

So obviously, wireless power transfer works in principle,

but how long before we can realistically have it in a domestic setting

so that you don't have to plug your telly into the wall?

I think it's going to be a long time

before any of us have houses big enough

to justify being powered with a laser beam.

Plus, if you did have one of those infrared lasers,

the kids would want to play in it all the time,

it's so lovely and warm,

thereby cutting off the telly when you most want to watch it.

So "don't hold your breath" is the message.

Don't unplug your TV just yet.

Next time on Bang, we'll be looking at your energy levels.

What is it that makes them rise and fall through the day?

What happens to you if you don't drink enough water?

I just want to neck that.

And Jem finds out if it's possible to boost your energy levels

just by drinking beetroot juice.

-See you then.

-Bye!

Subtitles by Red Bee Media Ltd