Fame

The builder of the Lighthouse of Alexandria, Sostratus – disobeying orders from the pharaoh Ptolemy – engraved his name and a dedication to the sea gods on the tower base.

Academia

The technical term for the study of lighthouses is ‘pharology’, a word derived from Pharos, the island upon which the great Lighthouse of Alexandria once stood.

War

George Meade built many notable lighthouses in the US during the classical lighthouse period. He is remembered in history as the winning general in the Battle of Gettysburg.

Tallest

The tallest lighthouse in the world is the Yokohama Marine Tower in Yokohama, Japan. The structure flashes alternately green and red every 20 seconds.

Elemental

Originally lighthouses were lit merely with open fires, only later progressing through candles, lanterns and electric lights. Lanterns tended to use whale oil as fuel.

The dawn of the digital format has revolutionised the imaging industry and in turn the way we work our cameras. Furthermore the internal DNA of the camera body has been entirely restructured to make way for the new electrical system; or has it?

In fact film and digital cameras operate in a similar manner. Varying the size of the lens’s diaphragm (aperture) in tandem with the amount of time the shutter is open, focusing light on to the image detection material, the only difference being that this is now received in an electrical rather than chemical form.

A DSLR (digital single-lens refl ex) camera employs a mechanical mirror system that directs the light travelling through the attached lens upwards at a 90 degree angle allowing the photographer to compose the shot through the viewfinder. As the shutter button is pressed the exposure takes place: the mirror swings out of the way and the shutter opens allowing the lens to project the light on to the image sensor. In low light scenarios the shutter will need to stay open for a longer period of time for the image to be recorded, this is why photographers support their cameras with tripods as the smallest degree of camera shake will disturb the quality.

The sensor is formed of millions of pixels laid out in thousands of rows and columns: the more pixels or dots of light, the higher the megapixel count and in theory the higher the resolution. The light travels through a colour filter above the individual sensors and is converted from light waves into an analogue signal which is then processed through a digital convertor. Next the conversion is fine tuned through a series of filters that adjust aspects such as white balance and colour. The resulting image can be made into a JPEG by compressing the file size and discarding unnecessary pixels. The final image is shown on the LCD.

Pianos work by transmitting the vibrational energy of taught wire strings into a soundboard, which in turn converts the vibrational energy into sound.

The piano achieves this through both its construction materials and action mechanisms. Pianos consist of five main parts: the frame, soundboard, strings, hammers and keys. The frame is constructed from metal and serves as a stable, immobile platform from which its strings (metal wires) and soundboard (vibration to sound conversion mechanism) can vibrate efficiently.

Steel is used as it helps mitigate unwanted vibrational energy being transmitted to the rest of the piano and surrounding area, a problem that leads to distortion of produced sounds. The hammers act as a striking mechanism, and when the piano’s keys are pressed by the player, they rise to strike their corresponding strings in order to produce vibrational energy.

The physics of the piano work in a chain-reaction. When a key on the keyboard is pressed, a complex system of jacks, pivots and levers raise a suspended hammer upwards to strike an overhung string, as well as a string damper (a felt block) that, once the string is stuck, comes into contact with the string and ceases its vibration.

In the short time between the hammer striking the wire and damper ceasing its motion, the vibrational energy is carried down the string and over a ‘bridge’, a raised bridge-shaped structure over which the string is tightly stretched.

The bridge receives this vibrational energy and transfers it into the piano’s soundboard, a wooden board chosen for its resonant properties that through the principle of forced vibration vibrate at exactly the same frequency of the struck string. Consequently, due to the large, expansive size of the board, the quiet tone created by the string is increased, and produces a loud note.

To find about more about this amazing product from Ross Technology and other bright innovations for 2012, check out issue 29 on How It Works, on sale 29 December 2011.

For more on Asimo and other bright innovations for 2012, check out issue 29 of How It Works, on sale 29 December 2011.

A normal CD has a surface covered in microscopic bumps; a bump will signify a ‘0’ and a flat will signify a ‘1’ in the binary system and this is how data is read. This has to be different for a rewritable disc though. For this a dye is used to coat the surface. When writing on the CD the dye will either be opaque or clear with the two states representing the binary number system. The dye is designed to change between opaque and clear so the disc can be rewritten several times.

Answered by Claire Butler.

We’ve partnered with Hexbug to bring you the hottest toy of the moment. One lucky reader’s letter each month will win five Hexbug Nanos. These small robots will scurry around any flat surface and they’ll even work their way around obstacles, so keep your eye on them when you set them off!

Has something in the world of science really caught your eye? Maybe you visited a museum and were astounded by an exhibit? Is there a latest gadget you really can’t live without (or with)? Does something really excite you about the upcoming era of human space exploration? Or maybe you’ve driven one of the high-tech vehicles in our transport section and want to tell us what it’s like?

Whatever the reason there’s never been a better time to get in touch with How It Works, and we always love to hear from our readers. You can contact us in the usual means via Facebook and Twitter, but for those really insightful thoughts you’ll probably want to get in touch by post or email:

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Welding is a fabrication process in which metals and thermoplastics are joined together to produce and object or structure. These materials are commonly joined by the melting of a filler material (such as steel) at their boundary points, fusing them together. This coalescence is achieved with three main techniques: gas welding, arc welding and laser welding.

Gas welding, also commonly referred to as oxy-fuel welding, is the most common type of welding and also the oldest. This process works through the combustion of acetylene in an oxygen stream, with the gas funnelled to a point of focus (ie the welding stick; this can be a handheld or stationary, robotic applicator) where it is ignited to produce a high-temperature flame. Gas welding produces a welding flame of 3,100°C (5,612°F) and as such, is typically used to weld high-alloy steels. However, the flame produced in a gas-based system is typically less concentrated than other methods, leading to greater weld distortion.

Arc welding differs to gas welding significantly. This technique involves melting the work materials through an electrical arc. This is generated by attaching a grounding wire to the welding material and then placing another electrode lead against it, itself attached to an AC or DC power supply. When the electrode lead is drawn away from the materials it generates an electrical arc (an ongoing plasma discharge caused by the electrical breakdown of gas), which through its expelled heat, welds the materials at the welding tip. Unlike gas welding, arc welding produces a narrow and concentrated weld point.

Finally, laser welding – which is one of the newest and most expensive forms of welding – utilises a high-energy laser beam to fuse work materials. As the laser beam has a high-energy density, this technique can achieve a deep penetration and incredibly focused weld, with little surrounding distortion. Due to this, laser welding is commonly used in large industrial applications, where speed and finesse is of great importance.

OnLive is a cloud gaming service available in the United Kingdom and United States. It allows its users to directly stream games – be that single or multiplayer – directly and on-demand to their computer, television, laptop or tablet. This, in contrast to traditional digital stores such as Steam and Origin, enables games to be played without downloading any data files to a local computing device. In addition, due to data and processing power handled almost entirely from a remote machine, local devices can be barebones setups, acting really as just audio/visual access portals.

OnLive works, in essence, like a Virtual Network Computing (VNC) system. VNCs are graphical sharing systems that utilise an RFB (remote framebuffer) protocol to remotely control another computer. This allows the actions of the remote computer to be dictated through the local machine, with all keyboard, mouse and gamepad actions transmitted along with the graphical screen. So, in OnLive’s system, a thin client (the service’s interactive menu) is used by the user to select, stream and control content that is stored and processed in large remote data centres on their own devices.

As power and storage are of no consequence therefore in the local machine – with only enough computing power needed to run the thin client – the key facet of OnLive and all cloud-gaming services is bandwidth and internet connectivity. A fast internet connection is needed in order to maintain a constant two-way stream of data, with the user’s input commands through the thin client sent one way (to the data centre), and the data content and subsequent actions of the user’s input sent back. For example, OnLive necessitates a 2MBps connection in order to output content at a screen resolution of 1,024 x 576, while it requires a greater than 5MBps connection to output at 1,280 x 720. This is purely to ensure that there is no lag in the transference of data packets between machines.

The OnLive system is accessed in three distinct ways. Accessing the service via personal computer or Mac necessitates downloading and installing dedicated software. Once this is achieved, OnLive is accessed via launching an executable file, where content can be streamed directly over the user’s desktop. Similarly, OnLive is accessed via a tablet computer by downloading a free app – in the case of the Apple iPad, acquired through the App Store. Once installed this, when selected, launches OnLive’s tablet client, which when partnered with the service’s Bluetooth-connected wireless controller, allows titles to be streamed on the device’s screen. Finally, OnLive can be accessed through a user’s television. This method, however, necessitates OnLive’s MicroConsole TV Adapter, a small auxiliary system that sits between the router and the television and handles encoding/decoding processes of streams, as well as the connectivity of peripherals.

For more information, including an interview with OnLive’s president and CEO Steve Perlman, check out issue 28 of How It Works, on sale now.

And let’s not forget, to find out how chainsaws work, make sure you pick up issue 29 of How It Works, on sale Wednesday 30 November.