The ability of hovercraft to cross dry land as well as water has seen them employed in the military and tourism sectors for many years. Although once billed as the next generation of transportation, they have somewhat decreased in popularity over the last decade. Despite this, their usefulness is still readily apparent.

The core principle of a hovercraft is that the hull of the vehicle is suspended on top of a giant cushion of air, held in place by flexible rubber that allows it to traverse difficult terrain or choppy waves without being torn apart. At the centre of a hovercraft is a huge fan that fi res air downwards, pushing the hull off the ground as high as two metres (6.5 feet). Smaller fans on top of the hull push air backwards, giving the hovercraft forward momentum. Rudders direct this fl ow of horizontal air to allow a hovercraft to change its direction.

Traditional hovercraft have an entirely rubber base that allows for travel on land or sea, but others have rigid sides that, while suited only to water, can have propellers or water-jet engines attached for a quieter craft.

Transport

Inside a hovercraft

How do these incredible machines traverse both land and sea?
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Rockets like Saturn V, the one used to launch NASA’s Apollo and Skylab programs, are multi-stage liquid-fuelled boosters. The Saturn V is considered to be the biggest, most powerful and most successful rocket ever built.

The Saturn V was 110.6m tall, 10.1m in diameter and had a payload of 119,000kgs to low-Earth orbit.

There were three stages, followed by an instrument unit and the payload (spacecraft). The total mission time for this rocket was about 20 mins. The centre engine was ignited first, then engines on either side ignited. The first stage lifted the rocket to about 70m and burned for 2.5 mins.

When sensors in the tanks sensed that the propellant was low, motors detached the first stage. The second stage continued the trajectory to 176km and burned for six mins. About halfway through this stage’s ignition, the instrument unit took control of calculating the trajectory.

Second stage complete, solid-fuel rockets fired it away from the third stage. The third stage burned for 2.5 mins and stayed attached to the spacecraft while it orbited the Earth, at an altitude of 191.2km.

It continued to thrust and vent hydrogen before ramping up and burning for six more minutes, so the spacecraft could reach a high enough velocity to escape Earth’s gravity.

Space

See inside the Saturn V rocket

This illustrated cutaway of the Saturn V shows the 110m high rocket and its 3 stages in amazing detail with full notes
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Bus Transport

Why are London buses red?

Are London buses red because they were ordered to be painted thus by the Red Queen, or is it more to do with indicating where they are going? Find out all after the jump.
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Widely considered by academics to be one of the most influential inventions of the past 1,000 years, the printing press set in motion both the democratisation of knowledge and the establishment of our modern, knowledge-based economies.

For the first time, valued texts could be produced in their thousands and – thanks to the co-evolution of nationwide and international trade routes – allowed texts to be accessed widely by the majority, not just the wealthy aristocracy and intellectual elite.

The man credited with the invention of the printing press is inventor Johannes Gutenberg, who lived and invented the press in Mainz, Germany. Here, around the year 1440 – an exact date is not known – Gutenberg designed a device based on screw presses that, when partnered with inked movable type heads, allowed paper to be quickly and efficiently pressed with letters.

The type heads were made by pouring a lead-tin alloy into a hand mould, and were then affixed to the top of movable, rectangular stalks. The stalks could then be arranged in order to create words and sentences within a rectangular container, before being fed under a screw press. The screw press then clamped a paper sheet on top of the type heads, pressing their ink onto the sheet.

While sounding crude by modern standards, in the 15th Century this was a groundbreaking invention. Before the Gutenberg press, texts were largely hand copied by monks and select few learned individuals. As such, the availability and cost of these texts was immense and they could only be accessed by a minuscule percentage of people.

Consequently, by the mid 16th Century and on to the Renaissance, printing presses had exploded all over Western Europe, producing millions of mass-produced texts on a diverse array of topics from politics to botany. Indeed, famous English philosopher Francis Bacon said that the emergence of typographical printing had “changed the whole face and state of things throughout the world.”

History

See inside the Gutenberg printing press

This exploded diagram of the Gutenberg printing press gives you a glimpse inside one of the most influential inventions of the past 1,000 years
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How It Works Facebook Activity

Designed in the aftermath of the evacuation of Dunkirk by the British Expeditionary Force, the Churchill tank was Britain’s attempt to readdress the technology gap between their ageing Matilda II battalion and the German Panzer tanks that had them out- gunned.

The result was the Mark I, a heavily armoured battle tank equipped with a two- pounder main gun, three-inch howitzer in the rear and the most advanced and robust suspension system yet conceived. It was a defensive juggernaut, designed with one goal: to dominate the European theatre of war.

From its introduction in June 1941, the tank proved a reliable and versatile weapon platform capable of engaging targets quickly and efficiently. Key to this was its high speed of 26km/h (16mph) and excellent turning ability, characteristics made possible by its multiple-bogie suspension system. The suspension was fitted to the hull under two large pannier enclosures on either side, with the tracks running over the top.

Initially, the Churchill was fitted with a two- pounder main gun and three-inch howitzer (artillery piece); however, the former was soon upgraded to a six-pounder cannon and the latter replaced with a high-calibre machine gun.

These cannons gave the Churchill decent stopping power against medium armour, yet still left them short in firepower when compared with their German contemporaries. The Churchill’s main cannon continued to be improved throughout its lifespan, with 75mm guns fitted to Mk IIIs.

Despite its average firepower, however, the Churchill’s high manoeuvrability and excellent armour made it one of the foremost tanks of WWII, being extensively deployed in Europe and North Africa.

History

See inside a Churchill Mk VII tank

Check out our illustrated guide to one of the most successful Churchill variants of World War II to discover what made it so ruthless, reliable and iconic
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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.

Technology

See inside a grand piano

This annotated cutaway diagram shows what goes on inside the piano when it plays
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