'Robocop' gadget developed for police

[Ikhlaas]

'Robocop' gadget developed for police (http://www.telegraph.co.uk/news/newstopics/politics/lawandorder/5480527/Robocop-gadget-developed-for-police.html)

I'm not exactly knowledgeable on the subject, but is this not the same as them handheld security scanners they use in airports when the buckle in your shoe sets of the metal detectors?

Also,

The lightweight handheld unit uses high frequency microwaves to see through clothes and pick up "reflections" of concealed guns or knives from a distance of several metres.

I think I'm correct in thinking microwave ovens work by emitting microwaves at the resonant frequency of water. This causes the water to resonate and heats it up. Since the body is roughly 65% water, am I wrong in thinking this idea is fatally flawed?

[TVC_H4U]

Yeh, May give you cancer maybe... I see anouther flaw, which is a knife/gun disgise such as:
http://www.dialaphone.co.uk/blog/wp-content/uploads/2007/02/swiss-army-phone.jpg

[Ikhlaas]

Lol. :rotfl:

I remember reading a couple of years back that there's a concern among those who use their mobile excessively. The mobile emits microwaves which heats up you brain. Extensive use could frazzle your brain!

I've just found this article from 1999 concerning the issue (http://news.bbc.co.uk/1/hi/health/507112.stm).

[Fishbone]

Microwave ovens do work by emitting microwaves at the resonant frequency of water, I'd assume they'd use a different frequency so they avoid cooking everyone they scan. There is a pretty large band of frequencies, 300MHz-300GHz, that are classed as microwaves. Just incase you're interested the resonant frequency of water is 2.45GHz, which is the frequency microwave ovens use.

A-Level physics has it's uses.

[RochdaleRed]

Fishbone is that what they are teaching now in A level Physics, how a microwave works lmao.
RR

[Ikhlaas]

Microwave ovens do work by emitting microwaves at the resonant frequency of water, I'd assume they'd use a different frequency so they avoid cooking everyone they scan. There is a pretty large band of frequencies, 300MHz-300GHz, that are classed as microwaves. Just incase you're interested the resonant frequency of water is 2.45GHz, which is the frequency microwave ovens use.

A-Level physics has it's uses.

From a bit of searching on wikipedia....

Resonant frequency of water = 2.45 GHz (As Fishbone said)
Microwave oven microwave frequency = 2.45 GHz (As you would expect)

Frequency of Wireless LAN/ Bluetooth = 2.40 GHz


Something to put worried minds at rest. (http://en.wikipedia.org/wiki/Mobile_phone_radiation_and_health#Mobile_phones_an d_cancer)

[Fishbone]

not exactly, you have to learn about waves etc. my teacher just threw in the microwave stuff because it's an everyday item that people are familiar with, plus it's also a good way to explain resonance.

[Ikhlaas]

Fishbone is that what they are teaching now in A level Physics, how a microwave works lmao.
RR

They do! It involves resonance (http://en.wikipedia.org/wiki/Resonance) which is important stuff!

It's better than what I had to learn at GCSE physics...
'Candidates are expected to understand and explain the moral and social implications of CCTV and streetlighting!'

Note: Not how the physics behind CCTV or streetlighting works!

[Fishbone]

From a bit of searching on wikipedia....

Resonant frequency of water = 2.45 GHz (As Fishbone said)
Microwave oven microwave frequency = 2.45 GHz (As you would expect)

Frequency of Wireless LAN/ Bluetooth = 2.40 GHz


Something to put worried minds at rest. (http://en.wikipedia.org/wiki/Mobile_phone_radiation_and_health#Mobile_phones_an d_cancer)

0.05GHz (50MHz) is quite a big difference, in fact it's a difference of 50 million oscillations per second, which is a lot.

[RochdaleRed]

Just remembered a story. I was travelling through a local airport and took my denim jacket off passed in on conveyor belt collected it other side and walked off. Only later when i was sat with my wife in departures had i remembered i had a knife in my top pocket which i use for fishing. I forgot it was there but they never picked me up on it. Scary

RR

[Fishbone]

They do! It involves resonance (http://en.wikipedia.org/wiki/Resonance) which is important stuff!

It's better than what I had to learn at GCSE physics...
'Candidates are expected to understand and explain the moral and social implications of CCTV and streetlighting!'

Note: Not how the physics behind CCTV or streetlighting works!

Haha, I remember GCSEs, when every exam had to have a morality/environment question.

[Ikhlaas]

0.05GHz (50MHz) is quite a big difference, in fact it's a difference of 50 million oscillations per second, which is a lot.

Yes, I'm glad that you've emphasized that! I kind of forgot! :struggle:

[Ikhlaas]

Haha, I remember GCSEs, when every exam had to have a morality/environment question.

Ye, very true! (I have the feeling that we may have sat the same exams!)

The most useful thing I learnt throughout my two years of GCSE studies was how to wire a plug.

(The most fun was probably learning about hurricanes, anti-cyclones and depressions in geography)

[Fishbone]

We would have sat them in the same year, depends which exam board your school used, mine was AQA for the sciences.

[Ikhlaas]

We would have sat them in the same year, depends which exam board your school used, mine was AQA for the sciences.

Yes, we did! I sat AQA for most of my exams for GCSE. Maths was Edexcel and Economics, OCR.

*Addition*

For those who don't know, or haven't seen the disastrous affects of resonance:

Galloping Gertie (http://www.youtube.com/watch?v=j-zczJXSxnw) - Basically, the wind was consistently causing the bridge to vibrate at it's resonant frequency!

[Fishbone]

My maths was Edexcel too as was Electronics, all the others were OCR.

All my A-Levels were AQA.

My only memory of the Electronics exam was the last question, it was something like 'give 2 reasons why outdoor cables that are improperly installed might be a danger to rabbits and other wildlife?' :rotfl:

[Ikhlaas]

My maths was Edexcel too as was Electronics, all the others were OCR.

All my A-Levels were AQA.

My only memory of the Electronics exam was the last question, it was something like 'give 2 reasons why outdoor cables that are improperly installed might be a danger to rabbits and other wildlife?' :rotfl:

:rotfl: Poor rabbits!

I can't really remember my GCSE exams that well. I remember that I found the maths paper two exam the first time I enjoyed maths (despite being good at it)! :)

[Fishbone]

I can't remember much about the actual exams, just the silly things really. A-Level stuff seems to have stuck though, probably because I need most of it for my degree.