Tedswoodworking

Are you one of those people who have some basic carpentry skills and enjoy building woodworking crafts/projects and want to create woodworking projects easily and quickly but wondering how?

You see, like you I wanted to try my hand at making some bunk beds for my two kids and my search brought me to this website.

The site is TedsWoodworking with over 16,000 (yes, you read right, 16,000!) downloadable woodworking plans and I decided to give it a try. To be frank, I was very skeptical at first as all kinds of websites for the exact same thing exist on the internet and you have to be careful. Besides, I was wondering how one person could possibly put together so many plans and woodworking blueprints. But Ted did it and it will interest you the same way it did me because it was the best that I have ever seen: Click here

Very Useful Bonuses

When you order Ted’s Woodworking package you will get these 3 handsome bonuses:

1. Free drawing and CAD plan viewer
2. 150 premium woodworking videos
3. The Complete Woodworking Carpentry Guide

The Complete Woodworking Carpentry Guide is a 200-page guide filled with carpentry tips and tricks. This makes it very useful for beginners. Besides, the premium videos can help any woodworker to hone his carpentry skills.

Surprisingly Organized Woodworking Ideas Plans

With this many plans (16,000, you remember!), you’d expect Ted’s Woodworking plans to be confusing. But no. I found it pretty easy to find the exact project I wanted, and you would too.

Money Back Guarantee

Ted McGrath trusts his plans so much that his product comes with 60 days money back guarantee. Should you in any event not be completely satisfied with what you get (which I doubt very much), you will simply receive your money back. No questions asked. You cannot get any better deal than that.

Downloadable Woodworking Project Plans

Wouldn’t it be nice to get instant access to over 16,000 woodworking plans?

It would if you know the frustration of thumbing through stacks and stacks of projects on woodworking in magazines and books of all kinds for some instructions on how to do a certain project. What about if you could have your woodworking plans (actually thousands of them) available to you anytime you wanted them, right there at your fingertips?

If you are starting a woodworking project, of course you need all the necessary information, such as schematics, blueprints, materials lists, dimensions etc. That is where Ted’s Woodworking Plans come in handy. They are not only clearly drawn but also are provided with step-by-step explanations of how the plan should be done and put together, thus saving you a lot of frustrations and headaches.

If you’ve tried other woodworking plans before, you’d agree with me that this is in direct contrast to the other sites whose collection of plans has the dimensions totally wrong without any indication of parts lists, material lists or the tools needed. If you’re one of those people who have bought such plans, you know how disappointing it can be! And maybe you’ve sworn never to buy another woodworking plan again. But Ted’s Woodworking Plans will change that perception forever.

This is because in Ted’s Woodworking you will get everything you need, such as:

-Detailed diagrams with a full set of dimensions
-Step -by-step instructions about how to start your project
-The necessary materials for your particular project
-All the woodworking tools you will need for your project.

Are Ted’s Woodworking Plans Worth the Money?

A resounding yes! Especially as each and every day Ted receives reports about people who have actually completed some of the projects included in package.

I figured that with a unconditional money back guarantee that I was given and after a period of sixty days that I had nothing to lose. All I had to do if it was not what I was looking for would be to send it back and get my money back. You cannot get any better deal than that.

I even read a review where the author said that they’ve been a carpenter for almost 36 years, and they haven’t found anything like Ted’s Woodworking Plans for less than 10’s of thousands of dollars. His final say? If you are planning to start on your woodworking project, Ted’s isn’t only the one that you SHOULD use, but you would be insane not to.

So don’t hesitate to join the 3763+ (and counting) other hobbyists, beginners, craftsmen and professionals who are happily using Ted’s Woodworking blueprints, plans and step-by-step directions to create stunning, professional woodworking projects, effortlessly and on time.

But you have to take action now because the offer for this is ENDING very soon. Ted will be selling all the plans and bonus independently in the future for $47-$97 EACH in the weeks and months ahead. So lock yourself in for a deep discount now!

Click Here

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Latest Technology Inventions

The latest technology invention in environmental pollution is a tower that cleans outdoor air.

The Tower is a seven-metre (23 feet) high structure that removes ultra-fine particles from the air using a patented ion-technology developed by scientists at Delft University of Technology.

According to the World Health Organization, air pollution causes the greatest environmental threat to our health.

Air pollution causes respiratory and cardiovascular disease and accounts for over 7 million premature deaths every year - and that death toll is rising at an alarming rate.

In California, where residents suffer from the worst health impacts of dirty air in the United States, air pollution causes premature death for 53,000 residents every year.

In London, England, dirty air accounts for one out of every twelve deaths.

In Delhi, India, the average life expectancy is shortened by 6.3 years due to air pollution.

China has the worst air in the world. Beijing recently recorded pollution levels that were 17 times greater than the acceptable levels recommended by the World Health Organization.

Air pollution causes 1.6 million deaths every year in China - approximately 17% of all deaths.

For most countries, the deadliest form of air pollution is a fine particle known as "PM 2.5" (particulate matter 2.5). It is so named because it is a fine particle that is only 2.5 micrometers in diameter. Unlike larger air-borne particles that settle to the ground, PM 2.5 particles can float in the air for weeks.

When you breath these particles into your lungs , they penetrate your lung tissue and get absorbed unfiltered into your blood stream - causing damage to your body.

The problem with current air pollution control systems is that they reduce but do not eliminate pollution.

Dutch innovator Daan Roosegaarde , in collaboration with ENS Technology and the Delft University of Technology, developed large scalable towers that remove pollution emitted into the air.

This technology was originally developed to remove MRSA bacteria (a type of bacteria resistant to antibiotics) from dust particles. The bacteria would spread from human to human by traveling in the air on dust. The air ionizer prevented the bacteria from spreading in this way.

Roosegaarde's Tower cleans 30,000 cubic meters of air per hour without using ozone and uses about 1,400 Watts of electricity - less than a desk-top air purifier.

Air from the area surrounding the Tower is drawn into the structure. All airborne particles receive an electric charge.

The charged particles are captured and accumulate on large collector plates that have an opposite electric charge.

The clean air is then blown from the Tower back into the environment.

"Basically, it's like when you have a plastic balloon, and you polish it with your hand, it becomes static, electrically charged, and it attracts your hair," explains Roosegaarde.

The invention won the German Design Award for Excellent Product Design awarded by the German Ministry for Economics and Technology.

The Tower is currently being tested in Beijing by the Chinese Ministry of Environmental Protection.

“We're working now on the calculation: how many towers do we actually need to place in a city like Beijing. It shouldn't be thousands of towers, it should be hundreds. We can make larger versions as well, the size of buildings,” says Roosegaarde.

Cloud Computing

Analysts predict that the latest technology inventions in cloud computing will significantly influence how we use our computers and mobile devices.

Cloud computing is where tasks and file storage on your computer are performed and stored elsewhere.

By using an internet connection you can connect to a service that has the architecture, infrastructure and software to manage any task or storage requirement at less cost.

The advantages of cloud computing is that it eliminates the difficulty and expense of maintaining, upgrading and scaling your own computer hardware and software while increasing efficiency, speed and resources.

Your computer's processing speed, memory capacity, software applications and maintenance requirements are minimized.

You could store and access any size or type of file, play games, use or develop applications, render videos, word process, make scientific calculations, or anything you want, by simply using a smart phone.

As a comparison, let's say you had to generate your own electricity. You would need to maintain, upgrade and scale these resources as required to meet your demands. This would be expensive and time consuming.

Cloud computing could be compared to how a utility provides electricity. It has the architecture, infrastructure, applications, expertise and resources to generate this service for you. You just connect to their grid.

Detecting walking speed with wireless signals

We’ve long known that blood pressure, breathing, body temperature and pulse provide an important window into the complexities of human health. But a growing body of research suggests that another vital sign – how fast you walk – could be a better predictor of health issues like cognitive decline, falls, and even certain cardiac or pulmonary diseases.

Unfortunately, it’s hard to accurately monitor walking speed in a way that’s both continuous and unobtrusive. Professor Dina Katabi’s group at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) has been working on the problem, and believes that the answer is to go wireless.

In a new paper, the team presents “WiGait,” a device that can measure the walking speed of multiple people with 95 to 99 percent accuracy using wireless signals.

Watch Video

The size of a small painting, the device can be placed on the wall of a person’s house and its signals emit roughly one-hundredth the amount of radiation of a standard cellphone. It builds on Katabi’s previous work on WiTrack, which analyzes wireless signals reflected off people’s bodies to measure a range of behaviors from breathing and falling to specific emotions. 

“By using in-home sensors, we can see trends in how walking speed changes over longer periods of time,” says lead author and PhD student Chen-Yu Hsu. “This can provide insight into whether someone should adjust their health regimen, whether that’s doing physical therapy or altering their medications.”

WiGait is also 85 to 99 percent accurate at measuring a person’s stride length, which could allow researchers to better understand conditions like Parkinson’s disease that are characterized by reduced step size.

Hsu and Katabi developed WiGait with CSAIL PhD student Zachary Kabelac and master’s student Rumen Hristov, alongside undergraduate Yuchen Liu from the Hong Kong University of Science and Technology, and Assistant Professor Christine Liu from the Boston University School of Medicine. The team will present their paper in May at ACM’s CHI Conference on Human Factors in Computing Systems in Colorado.  

How it works

Today, walking speed is measured by physical therapists or clinicians using a stopwatch. Wearables like FitBit can only roughly estimate speed based on step count, and GPS-enabled smartphones are similarly inaccurate and can’t work indoors. Cameras are intrusive and can only monitor one room. VICON motion tracking is the only method that’s comparably accurate to WiGate, but it is not widely available enough to be practical for monitoring day-to-day health changes.

Meanwhile, WiGait measures walking speed with a high level of granularity, without requiring that the person wear or carry a sensor. It does so by analyzing the surrounding wireless signals and their reflections off a person’s body. The CSAIL team’s algorithms can also distinguish walking from other movements, such as cleaning the kitchen or brushing one's teeth.

Katabi says the device could help reveal a wealth of important health information, particularly for the elderly. A change in walking speed, for example, could mean that the person has suffered an injury or is at an increased risk of falling. The system's feedback could even help the person determine if they should move to a different environment such as an assisted-living home.

“Many avoidable hospitalizations are related to issues like falls, congestive heart disease, or chronic obstructive pulmonary disease, which have all been shown to be correlated to gait speed,” Katabi says. “Reducing the number of hospitalizations, even by a small amount, could vastly improve health care costs.”

The team developed WiGait to be more privacy-minded than cameras, showing you as nothing more than a moving dot on a screen. In the future they hope to train it on people with walking impairments from Parkinson’s, Alzheimer’s or multiple sclerosis, to help physicians accurately track disease progression and adjust medications.

“The true novelty of this device is that it can map major metrics of health and behavior without any active engagement from the user, which is especially helpful for the cognitively impaired,” says Ipsit Vahia, a geriatric clinician at McLean Hospital and Harvard Medical School, who was not involved in the research. “Gait speed is a proxy indicator of many clinically important conditions, and down the line this could extend to measuring sleep patterns, respiratory rates, and other vital human behaviors.”

Ballyhooed artificial-intelligence technique known as “deep learning” revives 70-year-old idea.

In the past 10 years, the best-performing artificial-intelligence systems — such as the speech recognizers on smartphones or Google’s latest automatic translator — have resulted from a technique called “deep learning.”

Deep learning is in fact a new name for an approach to artificial intelligence called neural networks, which have been going in and out of fashion for more than 70 years. Neural networks were first proposed in 1944 by Warren McCullough and Walter Pitts, two University of Chicago researchers who moved to MIT in 1952 as founding members of what’s sometimes called the first cognitive science department.

Neural nets were a major area of research in both neuroscience and computer science until 1969, when, according to computer science lore, they were killed off by the MIT mathematicians Marvin Minsky and Seymour Papert, who a year later would become co-directors of the new MIT Artificial Intelligence Laboratory.

The technique then enjoyed a resurgence in the 1980s, fell into eclipse again in the first decade of the new century, and has returned like gangbusters in the second, fueled largely by the increased processing power of graphics chips.

“There’s this idea that ideas in science are a bit like epidemics of viruses,” says Tomaso Poggio, the Eugene McDermott Professor of Brain and Cognitive Sciences at MIT, an investigator at MIT’s McGovern Institute for Brain Research, and director of MIT’s Center for Brains, Minds, and Machines. “There are apparently five or six basic strains of flu viruses, and apparently each one comes back with a period of around 25 years. People get infected, and they develop an immune response, and so they don’t get infected for the next 25 years. And then there is a new generation that is ready to be infected by the same strain of virus. In science, people fall in love with an idea, get excited about it, hammer it to death, and then get immunized — they get tired of it. So ideas should have the same kind of periodicity!”

Weighty matters

Neural nets are a means of doing machine learning, in which a computer learns to perform some task by analyzing training examples. Usually, the examples have been hand-labeled in advance. An object recognition system, for instance, might be fed thousands of labeled images of cars, houses, coffee cups, and so on, and it would find visual patterns in the images that consistently correlate with particular labels.

Modeled loosely on the human brain, a neural net consists of thousands or even millions of simple processing nodes that are densely interconnected. Most of today’s neural nets are organized into layers of nodes, and they’re “feed-forward,” meaning that data moves through them in only one direction. An individual node might be connected to several nodes in the layer beneath it, from which it receives data, and several nodes in the layer above it, to which it sends data.

To each of its incoming connections, a node will assign a number known as a “weight.” When the network is active, the node receives a different data item — a different number — over each of its connections and multiplies it by the associated weight. It then adds the resulting products together, yielding a single number. If that number is below a threshold value, the node passes no data to the next layer. If the number exceeds the threshold value, the node “fires,” which in today’s neural nets generally means sending the number — the sum of the weighted inputs — along all its outgoing connections.

When a neural net is being trained, all of its weights and thresholds are initially set to random values. Training data is fed to the bottom layer — the input layer — and it passes through the succeeding layers, getting multiplied and added together in complex ways, until it finally arrives, radically transformed, at the output layer. During training, the weights and thresholds are continually adjusted until training data with the same labels consistently yield similar outputs.

Minds and machines

The neural nets described by McCullough and Pitts in 1944 had thresholds and weights, but they weren’t arranged into layers, and the researchers didn’t specify any training mechanism. What McCullough and Pitts showed was that a neural net could, in principle, compute any function that a digital computer could. The result was more neuroscience than computer science: The point was to suggest that the human brain could be thought of as a computing device.

Neural nets continue to be a valuable tool for neuroscientific research. For instance, particular network layouts or rules for adjusting weights and thresholds have reproduced observed features of human neuroanatomy and cognition, an indication that they capture something about how the brain processes information.

The first trainable neural network, the Perceptron, was demonstrated by the Cornell University psychologist Frank Rosenblatt in 1957. The Perceptron’s design was much like that of the modern neural net, except that it had only one layer with adjustable weights and thresholds, sandwiched between input and output layers.

Perceptrons were an active area of research in both psychology and the fledgling discipline of computer science until 1959, when Minsky and Papert published a book titled “Perceptrons,” which demonstrated that executing certain fairly common computations on Perceptrons would be impractically time consuming.

“Of course, all of these limitations kind of disappear if you take machinery that is a little more complicated — like, two layers,” Poggio says. But at the time, the book had a chilling effect on neural-net research.

“You have to put these things in historical context,” Poggio says. “They were arguing for programming — for languages like Lisp. Not many years before, people were still using analog computers. It was not clear at all at the time that programming was the way to go. I think they went a little bit overboard, but as usual, it’s not black and white. If you think of this as this competition between analog computing and digital computing, they fought for what at the time was the right thing.”

Periodicity

By the 1980s, however, researchers had developed algorithms for modifying neural nets’ weights and thresholds that were efficient enough for networks with more than one layer, removing many of the limitations identified by Minsky and Papert. The field enjoyed a renaissance.

But intellectually, there’s something unsatisfying about neural nets. Enough training may revise a network’s settings to the point that it can usefully classify data, but what do those settings mean? What image features is an object recognizer looking at, and how does it piece them together into the distinctive visual signatures of cars, houses, and coffee cups? Looking at the weights of individual connections won’t answer that question.

In recent years, computer scientists have begun to come up with ingenious methods for deducing the analytic strategies adopted by neural nets. But in the 1980s, the networks’ strategies were indecipherable. So around the turn of the century, neural networks were supplanted by support vector machines, an alternative approach to machine learning that’s based on some very clean and elegant mathematics.

The recent resurgence in neural networks — the deep-learning revolution — comes courtesy of the computer-game industry. The complex imagery and rapid pace of today’s video games require hardware that can keep up, and the result has been the graphics processing unit (GPU), which packs thousands of relatively simple processing cores on a single chip. It didn’t take long for researchers to realize that the architecture of a GPU is remarkably like that of a neural net.

Modern GPUs enabled the one-layer networks of the 1960s and the two- to three-layer networks of the 1980s to blossom into the 10-, 15-, even 50-layer networks of today. That’s what the “deep” in “deep learning” refers to — the depth of the network’s layers. And currently, deep learning is responsible for the best-performing systems in almost every area of artificial-intelligence research.

Under the hood

The networks’ opacity is still unsettling to theorists, but there’s headway on that front, too. In addition to directing the Center for Brains, Minds, and Machines (CBMM), Poggio leads the center’s research program in Theoretical Frameworks for Intelligence. Recently, Poggio and his CBMM colleagues have released a three-part theoretical study of neural networks.

The first part, which was published last month in the International Journal of Automation and Computing, addresses the range of computations that deep-learning networks can execute and when deep networks offer advantages over shallower ones. Parts two and three, which have been released as CBMM technical reports, address the problems of global optimization, or guaranteeing that a network has found the settings that best accord with its training data, and overfitting, or cases in which the network becomes so attuned to the specifics of its training data that it fails to generalize to other instances of the same categories.

There are still plenty of theoretical questions to be answered, but CBMM researchers’ work could help ensure that neural networks finally break the generational cycle that has brought them in and out of favor for seven decades.

Windows 10 S Locks You Into Edge and Bing, Out of Key Apps

Many school administrators love Chromebooks, precisely because Google's stripped-down operating system is like a pair of rubber training wheels for children who can't be trusted to drive a full-fledged OS. Microsoft is banking on schools purchasing laptops with Windows 10 S installed, because the company's new operating system severely limits which apps users can install while giving IT administrators fine control over your system.

Unfortunately, Windows 10 S also locks users into Microsoft's ecosystem, forcing you to use Edge as your browser and Bing as your default search engine while preventing you from installing a number of really important apps that don't appear in the Windows Store. If you're an educator, the lack of choice should give you pause and, if you're buying a laptop for yourself or your child, these training wheels are probably a deal breaker.

If you want to use Chrome, Firefox, Opera or pretty much any browser other than Edge, you should not get a laptop with Windows 10 S. In its support FAQ, Microsoft writes that:

"Microsoft Edge is the default web browser on Microsoft 10 S. You are able to download another browser that might be available from the Windows Store, but Microsoft Edge will remain the default if, for example, you open an .htm file. Additionally, the default search provider in Microsoft Edge and Internet Explorer cannot be changed." (emphasis mine)

I just checked the Windows Store, and I can't find any other major browsers there (or even minor ones). There's an entry for Opera browser, but when you install it, you just get a window with a download button which directs you to opera.com to actually download the app.

Perhaps some day, Google and Mozilla will get their browsers into the Windows Store. However, even if that happens, Edge will still be the default browser which opens any time you click a link in an email, a chat app or anywhere else in Windows 10 S. And every time you search by typing a query into Edge's address bar, you'll get results from Bing, with no option to change it to Google.

Now, to be fair, many people like using Edge browser, which is fast and has a clean UI. However, if you need any kind of browser extension to make a website work, you probably won't be able to use it on Edge. At present, Edge has only 32 extensions and, unlike Mozilla and Google who let anyone publish an extension, Microsoft hand picks the few developers that can do it.

Some web services just can't work with Edge right now. For example, at work, we use a single sign-on service called Okta, which requires a plugin to work, a plugin which isn't available for Edge. A number of conferencing apps, including Bluejeans and Zoom, require either plug-ins (which Edge doesn't have) or downloadable apps, which aren't in the Windows Store. My mother is a college professor who sometimes grades standardized tests on the weekends, and the online tool she is required to use will only work on Chrome or Firefox.

Microsoft says that Windows 10 S will work with every app in its Windows Store. However, nearly two years after the store launched with Windows 10, a lot of the most important programs aren't available in the store. Here are a few of the many apps which weren't available when I wrote this article:

• Visual Studio Community / Professional / Enterprise -- Microsoft's own development tool is not in its store so forget about teaching kids to program Windows apps on their Windows 10 S computers.
• Adobe Photoshop / Adobe Premiere -- You can get the lightweight Adobe Photoshop Express and Photoshop Elements, but forget about the professional versions of Adobe's creative suite.
• Notepad++ -- My favorite text editor is great for coding and building web pages. You won't find it in the store. There are other text editors in the store, though.
• Android Studio -- Kids who want to learn how to build apps for Android phones and tablets won't be able to get Google's official development kit.
• Google Drive -- You can visit Google Drive in your browser in Windows 10 S, but none of the Google client-side apps, including Google Drive, are in the store.
• Slack / Hipchat -- The two popular group chat apps aren't available in Windows Store.
• OpenVPN -- There are VPN apps in the Windows Store, but not this popular freeware program.
• WhatsApp -- Lots of kids chat with this, but they can't on WIndows 10 S.
• iTunes: Need to interface with your iPhone or download some media from Apple's store? Get a different Windows.

Hopefully, the developers of these apps and others will work with Microsoft to get into the Windows Store. It's almost certain that Microsoft will move its own apps (ex: Visual Studio) into the store at some point too. However, as of this writing, there are so many gaping holes in the store coverage.

For some schools, Windows 10 S's restrictions may initially be a strength rather than a weakness, but if those institutions want to use an education app that's not in the store or a web tool which won't function with Edge, they could have buyer's remorse. Fortunately, Microsoft is going to offer its EDU clients free upgrades to Windows 10 Pro, which I can imagine many of them using.

For individual users who are considering purchasing a Windows 10 S-powered computer like the Surface Laptop, Windows 10 S makes no sense at all. Would you really want to limit what apps and browsers you can use, right out of the box? Isn't the main benefit of Windows over Chrome OS the wide variety of software and services that you can use?

If you've been following Microsoft for a few years, you'll remember Windows RT, a failed version of Windows 8, which also only ran special Store apps. RT failed because of its lack of apps and Windows 10 S faces most of the same challenges. There's just one major improvement: any Windows 10 S user can pay $49 to upgrade to Windows 10 Pro, which can run every Windows program in the world and any browser you want. I expect a lot of people to pay that fee.

Fiber optics

The Romans must have been particularly pleased with themselves the day they invented lead pipes around 2000 years ago. At last, they had an easy way to carry their water from one place to another. Imagine what they'd make of modern fiber-optic cables—"pipes" that can carry telephone calls and emails right around the world in a seventh of a second!

Photo: Light pipe: fiber optics means sending light beams down thin strands of plastic or glass by making them bounce repeatedly off the walls. This is a simulated image. Note that in some countries, including the UK, fiber optics is spelled "fibre optics." If you're looking for information online, it's always worth searching both spellings.

What is fiber optics?

We're used to the idea of information traveling in different ways. When we speak into a landline telephone, a wire cable carries the sounds from our voice into a socket in the wall, where another cable takes it to the local telephone exchange. Cellphones work a different way: they send and receive information using invisible radio waves—a technology called wireless because it uses no cables. Fiber optics works a third way. It sends information coded in a beam of light down a glass or plastic pipe. It was originally developed for endoscopes in the 1950s to help doctors see inside the human body without having to cut it open first. In the 1960s, engineers found a way of using the same technology to transmit telephone calls at the speed of light (normally that's 186,000 miles or 300,000 km per second in a vacuum, but slows to about two thirds this speed in a fiber-optic cable).

Optical technology

A fiber-optic cable is made up of incredibly thin strands of glass or plastic known as optical fibers; one cable can have as few as two strands or as many as several hundred. Each strand is less than a tenth as thick as a human hair and can carry something like 25,000 telephone calls, so an entire fiber-optic cable can easily carry several million calls.

Fiber-optic cables carry information between two places using entirely optical (light-based) technology. Suppose you wanted to send information from your computer to a friend's house down the street using fiber optics. You could hook your computer up to a laser, which would convert electrical information from the computer into a series of light pulses. Then you'd fire the laser down the fiber-optic cable. After traveling down the cable, the light beams would emerge at the other end. Your friend would need a photoelectric cell (light-detecting component) to turn the pulses of light back into electrical information his or her computer could understand. So the whole apparatus would be like a really neat, hi-tech version of the kind of telephone you can make out of two baked-bean cans and a length of string!

Photo: Left: A section of 144-strand fiber-optic cable. Each strand is made of optically pure glass and is thinner than a human hair. Picture by Tech. Sgt. Brian Davidson, courtesy of US Air Force.

How fiber-optics works

Photo: Left: Fiber-optic cables are thin enough to bend, taking the light signals inside in curved paths too. Picture courtesy of NASA Glenn Research Center (NASA-GRC).

Light travels down a fiber-optic cable by bouncing repeatedly off the walls. Each tiny photon (particle of light) bounces down the pipe like a bobsleigh going down an ice run. Now you might expect a beam of light, traveling in a clear glass pipe, simply to leak out of the edges. But if light hits glass at a really shallow angle (less than 42 degrees), it reflects back in again—as though the glass were really a mirror. This phenomenon is called total internal reflection. It's one of the things that keeps light inside the pipe.

Artwork: Right: Total internal reflection keeps light rays bouncing down the inside of a fiber-optic cable.

The other thing that keeps light in the pipe is the structure of the cable, which is made up of two separate parts. The main part of the cable—in the middle—is called the core and that's the bit the light travels through. Wrapped around the outside of the core is another layer of glass called the cladding. The cladding's job is to keep the light signals inside the core. It can do this because it is made of a different type of glass to the core. (More technically, the cladding has a lower refractive index.)

Types of fiber-optic cables

Optical fibers carry light signals down them in what are called modes. That sounds technical but it just means different ways of traveling: a mode is simply the path that a light beam follows down the fiber. One mode is to go straight down the middle of the fiber. Another is to bounce down the fiber at a shallow angle. Other modes involve bouncing down the fiber at other angles, more or less steep.

Artworks: Above: Light travels in different ways in single-mode and multi-mode fibers. Below: Inside a typical single-mode fiber cable (not drawn to scale). The thin core is surrounded by cladding roughly ten times bigger in diameter, a plastic outer coating (about twice the diameter of the cladding), some strengthening fibers made of a tough material such as Kevlar®, with a protective outer jacket on the outside.

The simplest type of optical fiber is called single-mode. It has a very thin core about 5-10 microns (millionths of a meter) in diameter. In a single-mode fiber, all signals travel straight down the middle without bouncing off the edges (red line in diagram). Cable TV, Internet, and telephone signals are generally carried by single-mode fibers, wrapped together into a huge bundle. Cables like this can send information over 100 km (60 miles).

Another type of fiber-optic cable is called multi-mode. Each optical fiber in a multi-mode cable is about 10 times bigger than one in a single-mode cable. This means light beams can travel through the core by following a variety of different paths (purple, green, and blue lines)—in other words, in multiple different modes. Multi-mode cables can send information only over relatively short distances and are used (among other things) to link computer networks together.

Even thicker fibers are used in a medical tool called a gastroscope (a type of endoscope), which doctors poke down someone's throat for detecting illnesses inside their stomach. A gastroscope is a thick fiber-optic cable consisting of many optical fibers. At the top end of a gastroscope, there is an eyepiece and a lamp. The lamp shines its light down one part of the cable into the patient's stomach. When the light reaches the stomach, it reflects off the stomach walls into a lens at the bottom of the cable. Then it travels back up another part of the cable into the doctor's eyepiece. Other types of endoscopes work the same way and can be used to inspect different parts of the body. There is also an industrial version of the tool, called a fiberscope, which can be used to examine things like inaccessible pieces of machinery in airplane engines.

Try this fiber-optic experiment!

This nice little experiment is a modern-day recreation of a famous scientific demonstration carried out by Irish physicist John Tyndall in 1870.

It's best to do it in a darkened bathroom or kitchen at the sink or washbasin. You'll need an old clear, plastic drinks bottle, the brightest flashlight (torch) you can find, some aluminum foil, and some sticky tape.

1. Take the plastic bottle and wrap aluminum foil tightly around the sides, leaving the top and bottom of the bottle uncovered. If you need to, hold the foil in place with sticky tape.
2. Fill the bottle with water.
3. Switch on the flashlight and press it against the base of the bottle so the light shines up inside the water. It works best if you press the flashlight tightly against the bottle. You need as much light to enter the bottle as possible, so use the brightest flashlight you can find.
4. Standing by the sink, tilt the bottle so the water starts to pour out. Keep the flashlight pressed tight against the bottle. If the room is darkened, you should see the spout of water lighting up ever so slightly. Notice how the water carries the light, with the light beam bending as it goes! If you can't see much light in the water spout, try a brighter flashlight.

Photo: Seen from below, your water bottle should look like this when it's wrapped in aluminum foil. The foil stops light leaking out from the sides of the bottle. Don't cover the bottom of the bottle or light won't be able to get in. The black object on the right is my flashlight, just before I pressed it against the bottle. You can already see some of its light shining into the bottom of the bottle.

Uses for fiber optics

Shooting light down a pipe seems like a neat scientific party trick, and you might not think there'd be many practical applications for something like that. But just as electricity can power many types of machines, beams of light can carry many types of information—so they can help us in many ways. We don't notice just how commonplace fiber-optic cables have become because the laser-powered signals they carry flicker far beneath our feet, deep under office floors and city streets. The technologies that use it—computer networking, broadcasting, medical scanning, and military equipment (to name just four)—do so quite invisibly.

Computer networks

Fiber-optic cables are now the main way of carrying information over long distances because they have three very big advantages over old-style copper cables:

• Less attenuation: (signal loss) Information travels roughly 10 times further before it needs amplifying—which makes fiber networks simpler and cheaper to operate and maintain.
• No interference: Unlike with copper cables, there's no "crosstalk" (electromagnetic interference) between optical fibers, so they transmit information more reliably with better signal quality
• Higher bandwidth: As we've already seen, fiber-optic cables can carry far more data than copper cables of the same diameter.

You're reading these words now thanks to the Internet. You probably chanced upon this page with a search engine like Google, which operates a worldwide network of giant data centers connected by vast-capacity fiber-optic cables (and is now trying to roll out fast fiber connections to the rest of us). Having clicked on a search engine link, you've downloaded this web page from my web server and my words have whistled most of the way to you down more fiber-optic cables. Indeed, if you're using fast fiber-optic broadband, optical fiber cables are doing almost all the work every time you go online. With most high-speed broadband connections, only the last part of the information's journey (the so-called "last mile" from the fiber-connected cabinet on your street to your house or apartment) involves old-fashioned wires. It's fiber-optic cables, not copper wires, that now carry "likes" and "tweets" under our streets, through an increasing number of rural areas, and even deep beneath the oceans linking continents. If you picture the Internet (and the World Wide Web that rides on it) as a global spider's web, the strands holding it together are fiber-optic cables; according to some estimates, fiber cables cover over 99 percent of the Internet's total mileage, and carry over 99 percent of all international communications traffic.

The faster people can access the Internet, the more they can—and will—do online. The arrival of broadband Internet made possible the phenomenon of cloud computing(where people store and process their data remotely, using online services instead of a home or business PC in their own premises). In much the same way, the steady rollout of fiber broadband (typically 5–10 times faster than conventional DSL broadband, which uses ordinary telephone lines) will make it much more commonplace for people to do things like streaming movies online instead of watching broadcast TV or renting DVDs. With more fiber capacity and faster connections, we'll be tracking and controlling many more aspects of our lives online using the so-called Internet of things.

But it's not just public Internet data that streams down fiber-optic lines. Computers were once connected over long distances by telephone lines or (over shorter distances) copper Ethernet cables, but fiber cables are increasingly the preferred method of networking computers because they're very affordable, secure, reliable, and have much higher capacity. Instead of linking its offices over the public Internet, it's perfectly possible for a company to set up its own fiber network (if it can afford to do so) or (more likely) buy space on a private fiber network. Many private computer networks run on what's called dark fiber, which sounds a bit sinister, but is simply the unused capacity on another network (optical fibers waiting to be lit up).

The Internet was cleverly designed to ferry any kind of information for any kind of use; it's not limited to carrying computer data. While telephone lines once carried the Internet, now the fiber-optic Internet carries telephone (and Skype) calls instead. Where telephone calls were once routed down an intricate patchwork of copper cables and microwave links between cities, most long-distance calls are now routed down fiber-optic lines. Vast quantities of fiber were laid from the 1980s onward; estimates vary wildly, but the worldwide total is believed to be several hundred million kilometers (enough to cross the United States about a million times). In the mid-2000s, it was estimated that as much as 98 percent of this was unused "dark fiber"; today, although much more fiber is in use, it's still generally believed that most networks contain anywhere from a third to a half dark fiber.

Photo: Fiber-optic networks are expensive to construct (largely because it costs so much to dig up streets). Because the labor and construction costs are much more expensive than the cable itself, many network operators deliberately lay much more cable than they currently need. Picture by Chris Willis courtesy of US Air Force.

Broadcasting

Back in the early 20th century, radio and TV broadcasting was born from a relatively simple idea: it was technically quite easy to shoot electromagnetic waves through the air from a single transmitter (at the broadcasting station) to thousands of antennas on people's homes. These days, while radio still beams through the air, we're just as likely to get our TV through fiber-optic cables.

Cable TV companies pioneered the transition from the 1950s onward, originally using coaxial cables (copper cables with a sheath of metal screening wrapped around them to prevents crosstalk interference), which carried just a handful of analog TV signals. As more and more people connected to cable and the networks started to offer greater choice of channels and programs, cable operators found they needed to switch from coaxial cables to optical fibers and from analog to digital broadcasting. Fortunately, scientists were already figuring out how that might be possible; as far back as 1966, Charles Kao (and his colleague George Hockham) had done the math, proving how a single optical fiber cable might carry enough data for several hundred TV channels (or several hundred thousand telephone calls). It was only a matter of time before the world of cable TV took notice—and Kao's "groundbreaking achievement" was properly recognized when he was awarded the 2009 Nobel Prize in Physics.

Apart from offering much higher capacity, optical fibers suffer less from interference, so offer better signal (picture and sound) quality; they need less amplification to boost signals so they travel over long distances; and they're altogether more cost effective. In the future, fiber broadband may well be how most of us watch television, perhaps through systems such as IPTV (Internet Protocol Television), which uses the Internet's standard way of carrying data ("packet switching") to serve TV programs and movies on demand. While the copper telephone line is still the primary information route into many people's homes, in the future, our main connection to the world will be a high-bandwidth fiber-optic cable carrying any and every kind of information.

Medicine

Medical gadgets that could help doctors peer inside our bodies without cutting them open were the first proper application of fiber optics over a half century ago. Today,gastroscopes (as these things are called) are just as important as ever, but fiber optics continues to spawn important new forms of medical scanning and diagnosis.

One of the latest developments is called a lab on a fiber, and involves inserting hair-thin fiber-optic cables, with built-in sensors, into a patient's body. These sorts of fibers are similar in scale to the ones in communication cables and thinner than the relatively chunky light guides used in gastroscopes. How do they work? Light zaps through them from a lamp or laser, through the part of the body the doctor wants to study. As the light whistles through the fiber, the patient's body alters its properties in a particular way (altering the light's intensity or wavelength very slightly, perhaps). By measuring the way the light changes (using techniques such as interferometry), an instrument attached to the other end of the fiber can measure some critical aspect of how the patient's body is working, such as their temperature, blood pressure, cell pH, or the presence of medicines in their bloodstream. In other words, rather than simply using light to see inside the patient's body, this type of fiber-optic cable uses light to sense or measure it instead.

Military

Photo: Fiber optics on the battlefield. This Enhanced Fiber-Optic Guided Missile (EFOG-M) has an infrared fiber-optic camera mounted in its nose so that the gunner firing it can see where it's going as it travels. Picture courtesy of US Army.

It's easy to picture Internet users linked together by giant webs of fiber-optic cables; it's much less obvious that the world's hi-tech military forces are connected the same way. Fiber-optic cables are inexpensive, thin, lightweight, high-capacity, robust against attack, and extremely secure, so they offer perfect ways to connect military bases and other installations, such as missile launch sites and radar tracking stations. Since they don't carry electrical signals, they don't give off electromagnetic radiation that an enemy can detect, and they're robust against electromagnetic interference (including systematic enemy "jamming" attacks). Another benefit is the relatively light weight of fiber cables compared to traditional wires made of cumbersome and expensive copper metal. Tanks, military airplanes, and helicopters have all been slowly switching from metal cables to fiber-optic ones. Partly it's a matter of cutting costs and saving weight (fiber-optic cables weigh nearly 90 percent less than comparable "twisted-pair" copper cables). But it also improves reliability; for example, unlike traditional cables on an airplane, which have to be carefully shielded (insulated) to protect them against lightning strikes, optical fibers are completely immune to that kind of problem.

Who invented fiber optics?

• 1840s: Swiss physicist Daniel Colladon (1802–1893) discovered he could shine light along a water pipe. The water carried the light by internal reflection.
• 1870: An Irish physicist called John Tyndall (1820–1893) demonstrated internal reflection at London's Royal Society. He shone light into a jug of water. When he poured some of the water out from the jug, the light curved round following the water's path. This idea of "bending light" is exactly what happens in fiber optics. Although Colladon is the true grandfather of fiber-optics, Tyndall often earns the credit.
• 1930s: Heinrich Lamm and Walter Gerlach, two German students, tried to use light pipes to make a gastroscope—an instrument for looking inside someone's stomach.
• 1950s: In London, England, Indian physicist Narinder Kapany (1927–) and British physicist Harold Hopkins (1918–1994) managed to send a simple picture down a light pipe made from thousands of glass fibers. After publishing many scientific papers, Kapany earned a reputation as the "father of fiber optics."
• 1957: Three American scientists at the University of Michigan, Lawrence Curtiss, Basil Hirschowitz, and Wilbur Peters, successfully used fiber-optic technology to make the world's first gastroscope.
• 1960s: Chinese-born US physicist Charles Kao (1933–) and his colleague George Hockham realized that impure glass was no use for long-range fiber optics. Kao suggested that a fiber-optic cable made from very pure glass would be able to carry telephone signals over much longer distances and was awarded the 2009 Nobel Prize in Physics for this ground-breaking discovery.
• 1960s: Researchers at the Corning Glass Company made the first fiber-optic cable capable of carrying telephone signals.
• 1977: The first fiber-optic telephone cable was laid between Long Beach and Artesia, California.
• 1997: A huge transatlantic fiber-optic telephone cable called FLAG (Fiber-optic Link Around the Globe) was laid between London, England and Tokyo, Japan.