Science

Mitosis explained

Mitosis is the process by which our bodies replace cells. It starts with a diploid cell containing 46 chromosomes…
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History

The A7V

One of the earliest tanks, the A7V was supposed to deliver German soldiers a mobile fortress to break through Allied lines. The reality, however, didn’t quite live up to expectations…
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Space

Inside an airlock

Discover the key areas of the International Space Station’s Quest airlock with our interactive cutaway illustration
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Technology

NASCAR Teardown

While plain on the surface, a wide variety of awesome racing components goes into each NASCAR vehicle. Hover over the bullet points to reveal more.
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Technology

Bathyscaphe Trieste

The Bathyscaphe Trieste explored the deepest parts of Earth’s oceans and was the first manned vehicle to have reached the bottom of the Mariana Trench. Hover over the bullet points to reveal how it worked.
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Most homes are lucky enough to have one, but have you ever wondered how a washing machine works? After separating your laundry into whites and colours – so as to protect your whites from colour run – load your clothes into the main drum and close the door. Once you’ve programmed the machine to tell it what sort of wash you require – temperature, speed, length and so on – the machine then adds water and detergent and sloshes the clothes around. After a time, the drum will spin really fast – up to 80mph (130kph) – creating a centrifugal force that extracts most of the water out of the clothes and out through the holes in the inner drum where it is then pumped away.

Technology

How does a washing machine work?

We take a look inside one of these household appliances to see how it cleans our clothes.
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Not only does your heart do amazing things, it does so tirelessly, every minute of every day from the moment you’re born (actually, even a bit before then) to the instant that you die. It weighs somewhere between 0.2 to 0.3 kg – slightly more if you’re male, less if you’re female. Its sole purpose is to push blood through your circulatory system, providing crucial oxygen and other nutrients to all your organs.

The heart is considered a double pump because the right half sends ‘used’ blood to your lungs. There, the blood drops off a load of carbon dioxide and picks up some fresh oxygen, which you have helpfully provided by breathing. Then the oxygenated blood returns to the left half of the heart. This ‘heart-to-lungs-to-heart-again’ trip is known as pulmonary circulation. The left side of the heart then pumps this oxygenated blood to every organ in your body other than your lungs. Your brain, your skin, the muscles in your thigh, your spleen – they all get blood (and therefore oxygen) by virtue of your beating heart.

Even the heart itself gets blood, via a special set of veins and arteries known as the coronary system. The myocardial muscle within the wall of the heart needs oxygen and other nutrients to keep beating. Unfortunately, the coronary arteries that do this job are very narrow, between 1.7 and 2.2 millimeters in diameter. If they become clogged with cholesterol or other fatty deposits, the heart stops working. This is bad for you.

Of course, the relatively simple concept of the double pump is fairly complex in practice. A series of valves control blood flow to the heart’s four chambers, allow for the build-up of enough blood pressure to get the job done, and direct the blood to the correct veins and arteries.

Science

How does the heart work?

We take a look inside the heart to find out how it keeps us ticking.
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One of the most numerous armoured vehicles during World War II, the Soviet Union’s T-34 medium tank is considered by military historians to be one of the most important and influential tanks ever to be built.

Evolving out of the BT series of fast tanks (Soviet cavalry tanks with thin armour and high mobility), the T-34 at its introduction was the first tank to sport a complete balance between firepower, mobility, protection and longevity – something that modern tanks now take for granted. Further, it was an especially refined and simple design that allowed for costs (135,000 rubles) and production time frames to be kept low, meaning that many tanks could be produced in very little time and allow Russia to mitigate its higher-than-average losses quickly and cheaply. Indeed, this became a very important factor towards the end of the war when the superior – but hard and expensive to manufacture – German Tiger and Panther tanks could not be replaced fast enough.

The T-34 was fitted with a good balance of weaponry, sporting a 76.2mm F-34 tank gun – ideal for taking down medium and light armoured enemy vehicles – and twin 7.62mm DT machine guns, perfect against unarmoured targets and to suppress advancing soldiers. Its armour also offered a great balance between protection and weight, with up to 63mm of armour plating standing between its crew and the shells and bullets of the enemy. This meant that only the largest of enemy cannons – such as the 88mm beast fitted to the German Tiger tank – could breach its hull or turret and, considering its high top speed of 33mph, this was only possible if it became entrenched or caught unawares. By keeping the armour thickness to a medium level though, the total weight of the T-34 was kept down to 26 tons, under half that of the German Tiger and allowing the T-34 unrivalled dynamism in the field.

Historically, the T-34 will be remembered as the vehicle that swept German forces from Russia, advancing from Stalingrad all the way to Berlin in 1945. However, its usage continued right up to 1958, when it was finally replaced by its successor the T-54. Despite its official retirement however, the T-34 has continued to be used in Third World militaries right up to the present day and has also found itself bought and operated by both private collectors and military museums.

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History

T-34 Tank Cutaway

How It Works breaks down a T-34 tank to see what made it one of the most popular armoured vehicles of World War II
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A star with a mass of less than 1.5 solar masses (the mass of the Sun) forms a white dwarf at the end of its lifetime, owing to its gravity being too weak to collapse it further. If the mass of a star is greater than five solar masses, the forces will be so intense that the star collapses past the point of a neutron star and becomes a black hole. However, between these two extremes a neutron star will form as the result of a supernova, although only approximately one in a thousand stars will become one.

As a star runs out of fuel it will eventually collapse in upon itself. In the formation of a neutron star, the protons and electrons within every atom are forced together, forming neutrons. Material that is falling to the centre of the star is then crushed by the intense gravitational forces in the star and forms this same neutron material. Like the Earth, magnetic fields surround neutron stars and are tipped at the axis of rotation, namely the north and south poles. However, the magnetic field of a neutron star is more than a trillion times stronger than that of Earth’s.

The gravitational forces in a neutron star are also incredibly strong. The matter is so densely packed together into a radius of 20 kilometres (12 miles) that one teaspoon of mass would weigh up to a billion tons, about the same as Mount Everest. They also spin up to 600 times per second, gradually slowing down as they age.

Oddly enough, as a neutron star becomes heavier it also becomes smaller. This is because a greater mass means a greater force of gravitational attraction, and therefore the neutrons are squeezed more densely together. In fact, if you were able to drop an object from a height of one metre on the surface of a neutron star, it would hit the ground at about 2,000 kilometres (1,200 miles) per second.

Space

Peer inside a neutron star

We take a look into the heart of one of the most massive objects in the universe.
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Hurricanes are massive heat engines. They form over tropical waters with a minimum temperature of 27˚C (80.6˚F). Hot water evaporates very quickly, rising up through the atmosphere until it condenses into clouds and water droplets. The incredible thing is that condensation itself creates even more heat. The recharged air soars even higher, building a cluster of towering, fat thunderstorms called a tropical disturbance.

Once the heat engine has been jump-started, rapid condensation within the storm continues to force air upward while more hot air rushes in from below to fill the void. This suction of hot air from the ocean surface creates lower and lower air pressure. When air rushes from high pressure to low pressure, it creates powerful winds. When wind velocity reaches 38mph (60 kph), the storm is called a tropical depression.

Satellite images of hurricanes show a swirling vortex of storm clouds. The spin is caused by two main forces: the Coriolis force and the pressure gradient. In the northern hemisphere, the Earth’s rotation pulls winds to the right (Coriolis force), but the extreme low pressure at the storm’s centre pulls them back to the left, creating a net counter- clockwise spin. The opposite is true south of the equator. As the heat engine chugs on, more water condenses, more heat rises, the pressure drops further and spin increases until winds reach 38 to 75mph (60 to 120 kph), enough to qualify as a tropical storm. Seven out of ten tropical storms spin even faster than 75 mph (120 kph), officially becoming a hurricane.

Environment

Inside a hurricane

What’s going on inside this deadly force of nature?
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