Marvels of Science and Technology

Ever since the discovery of fire and the invention of the wheel, humans have continued to come up with innovations to make our lives easier. We now understand the causes of many diseases, and can search for ways of curing them by looking at individual cells and genes. After the steam engine and the Internet, nanotechnologies may be poised to usher in yet another technological revolution. More smart ideas will be called for if we are to feed the planet's huge population - soon to be 8 billion - and provide environmentally friendly energy.

Were all the important things invented back in the Stone Age ?

Clearly many important things were not invented during the Stone Age, however many developments did begin during that period. Religion, art, tools, hunting weapons, clothing, jewellery and farming are all examples of important innovations that emerged during the Stone Age.

When did human beings become civilised ?

Civilised doesn't necessarily mean the ability to use a knife and fork. Rather, the things that constitute a human being's degree of civilisation are the signs of culture and reason - characteristics that distinguish humans from the rest of the animal kingdom. These signs became apparent early on, and even Neanderthals had religious concepts. It is thought that by the late Stone Age people were already capable of bartering desirable goods rather than simply snatching them away from each other. Furthermore, the development of the key cultural technologies of writing and arithmetic took place in the final 5 to 10 000 years BC.

How long ago was money invented ?

Money-not in the form of coins and notes, but in the sense of a means of exchange - emerged very early in the history of humanity. Evidence for this is found, for example, in the term 'pecuniary'. This word is derived from the Latin pecus, which means cattle, and cattle were an accepted means of exchange in ancient times.

One of the oldest coins ever discovered - a tetradrachmon from Athens.

Scientists have found the earliest traces of money as a means of exchange in the Upper Palaeolithic period, starting about 30 000 years ago. Prior to that, objects found in graves gave no indication that they were being used as a means of exchange rather than simply as adornments. Coins were a relatively late invention, and had to be preceded by the realisation that cattle and other goods were an unwieldy means of exchange and posed a transport problem. The world's oldest coins are thought to have originated in Greece during the 6th century BC.

Will we all soon live for more than 100 years ?

There are already more than 135 000 people over 100 years old, and in the year 2050 their number will have swelled to 2 million, according to the World Health Organization. People who live to a great age have always existed, but there has been a rise in life expectancy because of improvements in hygiene and nutrition, accident prevention and the diagnostic and healing tools offered by modern medicine.

What happens when there are no doctors nearby ?

The faster a doctor can get to a patient, the better are his or her chances of a full recovery. However, there are many places around the world that do not have a regular health service. In the age of computers it is possible for a digital image or a webcam to allow a remote doctor to make an initial diagnosis. This is not unlike the way in which telemedicine works in developing countries. In an emergency, a simple telephone is sufficient to allow a consultant at the other end of the line to make use of the eyes and hands of less experienced personnel on the spot. The first ever transatlantic operation took place a few years ago when surgeons in New York performed an operation on a woman in France with the help of a remote-controlled robot. This is a method of particular interest to armed forces, since soldiers are frequently injured in remote areas.

Can every part of a human being be replaced ?

While there is little prospect of building a Frankenstein's Monster in the near future, devices. that perform the same function as some human body parts can already be manufactured. It will take a while before an artificial heart looks like a real one, but a mechanical heart can already take on all of the heart's functions until such a time as a suitable replacement is found for a transplant. Cochlear implants for those with defective hearing offer a very good replacement, as do nerve-controlled hand and foot prosthetics. Artificial kidneys and livers still operate outside the body, a blood substitute is still being developed, and replacement retinas for the blind can only provide shadowy sight.

Many scientists are hoping that biology rather than technology will hold the key to future developments. Using tissue-engineering techniques, they hope to build three-dimensional organs from real cells. Already available in real life are bone and cartilage parts, as well as tendons, heart valves and replacement skin grown in the laboratory from the body's own cells, which is used to help heal large wounds.

How are pacemaker batteries replaced ?

Pacemakers need to be fitted with a new battery once every eight to twelve years, and so far this has involved an operation every time one had to be replaced. The hope is that that this may be avoided in future, thanks to new developments. One Japanese invention is a device with a solar cell that is inserted under the skin. When an infrared laser beam is directed at it, the battery is recharged. In America, scientists are working on implants that are automatically provided with a lasting supply of energy from tiny, thermoelectric elements that derive their energy from the body's own heat. Other researchers are working on a biofuel cell - a mini-battery that takes its energy from the blood. It imitates natural metabolic reactions involving blood sugar and oxygen, transforming chemical energy into electrical energy.

Will computers just keep on improving ?

Since the invention of the first programmable calculators in the 1930s, computers have continued to develop at an incredible speed. According to Moore's Law, computing power is projected to continue doubling every 12 to 24 months. With today's silicon technology this is likely to continue for the next decade, after which many expect nanotechnology to take over.

Will machines learn to think and feel ?

When it comes to the game of chess, human beings are no longer any match for machines. Computers understand language (at least in a limited sense), are able to network and arrive quickly at a solution for some very complex problems. In the 1980s, many experts thought that computers would one day develop artificial intelligence and were therefore likely to learn to think and feel independently. Since then, however, some scientists have rejected that as a possible scenario.

Can computers prevent wars? 

Although computers have become indispensable in the development of combat strategies, the thought that they could prevent wars is just a hope. Going to war is a decision that - so far - only humans make, and it is highly unlikely this will ever change. However, computers can quickly provide unemotional projections of the realistic consequences of a war. It is to be hoped that outcomes involving senseless loss of life may convince warmongers to avoid rash and dangerous strategies.

Can the human brain be replaced by a computer ?

Theoretically, it seems possible that sometime in the future there may be a computer that is capable of duplicating the memory feats and computing abilities of a human brain. However, some time will have to pass before that happens.

This is because- with about 100 billion nerve cells, each of which is connected to another 10 000 or so neurons - the natural neural networks inside our heads still make any computers look slow. In particular, the ability to process many stimuli and signals in parallel is still underdeveloped in computers. Currently the world's fastest supercomputer-BlueGene/L at the Lawrence Livermore National Laboratory in the USA-performs 280.6 trillion calculations per second-in computing jargon, 280.6 teraflops. It has been calculated that even a rough replication of the human brain would require a machine capable of at least 10 000 teraflops.

Do physics and chemistry still hold surprises ?

Even the simplest of real world phenomena are complex in their details. New insights in physics and chemistry reveal new ways of doing everyday tasks. New technologies and materials are required for our ever more complex modern way of life, and even the traditional tried and tested ways of doing things may well benefit from being made more environmentally friendly and less energy-hungry.

Is it possible for anything to be harder than a diamond ?

Diamond is the hardest of all natural materials, but it is possible make harder synthetic materials from compressed C60 molecules, a material known as buckyballs. As with diamond, buckyballs are pure carbon, except that the atoms are arranged in the shape of a football. Thanks to their symmetry, the molecules can be packed very densely, and although the material is as soft as a lead pencil under standard pressure, it becomes ultra-hard when tightly compressed. Scientists have been able to press the buckyballs into tiny rods at very high temperatures and pressures of about 200 000 times that of atmospheric pressure. At 492 gigapascals, the pressures are the highest ever achieved. Diamonds are produced at pressures of about 442 gigapascals.

Where will our energy come from in the future ?

Energy is becoming an increasingly sought after commodity - especially in the booming economies of China and India, where the demand is rising all the time. This is why there is now a worldwide search for new energy sources, preferably the kind of energy that makes a minimal contribution to global warming. At the same time, engineers are increasing the amount of power produced by conventional power plants.

How can energy be stored ?

When it comes to oil, coal and natural gas, nature shows us how best to store the energy made by the sunlight that fell to Earth many aeons ago. However, human beings have yet to invent a comparatively efficient and easily transportable means of energy storage. Developing one is among the greatest challenges facing today's power industry, particularly because wind turbines and solar power plants only produce energy in areas that have a lot of wind or Sun, while the energy itself is generally needed elsewhere. Although batteries work well in motor vehicles and mobile phones, they would be far too bulky and expensive for storing larger amounts of power. Some experts believe that hydrogen will provide the power source of the future. One way of exploiting it is to use surplus power to split water into its component parts of hydrogen and oxygen. Using these two gases - which can be stored and transported - a fuel cell could generate electricity anywhere. Large amounts of energy are lost in the conversion, however.

Are we about to see a new industrial revolution ?

About 20 years ago, the invention of new, high-resolution microscopes allowed scientists to examine the fine structure of matter in much greater detail. The tiniest particles were a surprise to scientists because they exhibited characteristics that were not previously observed in larger objects - nanotechnology was born and it has gone from strength to strength ever since. Incidentally, the term 'nano' is derived from the Greek for dwarf. Self-cleaning surfaces, quicker computer chips and possibly even new cancer treatment methods are based on nanotechnology.

What does a gene look like ?

As a rule, genes are sections of different lengths of the DNA molecule. The sequence of the gene's building blocks contains the information needed to produce proteins. Other parts of the sequence serve as a kind of 'switch' that proteins can attach themselves to in order to either block or activate a gene.

FOCUS

What makes humans unique ?

As far we know, animals other than humans do not have a concept of time, are unaware that they must die one day and have no concept of beauty. We can only speculate about why and when these ideas became so significant for humans.

Why is it that for thousands of years, graves were made of stone?

Burying the dead in wooden boxes was inconceivable to people of the Stone Age. They had to be laid to rest in a stone chamber or graves protected by stones. Early European and Egyptian tombs provide strong evidence that stone was thought to preserve the afterlife of the dead.

Why do calendars sometimes differ from country to country?

It is possible that the recognition of their own mortality gave human beings the desire to give time a structure, which they did with the help of calendars.

In principle, calendars are based on observations of nature and the sky. However, the significance of different phenomena varied between cultures. The Moon was the principal god of the Sumerians, who ruled southern Mesopotamia from about 2900 BC onwards. The reliability of the lunar phases commanded their respect and they consequently had a lunar year. A thousand years later the Sun became the chief god of the Babylonians and the solar year replaced the lunar year. In Egypt, the Nile was responsible for the structure of the calendar, because its floods were always punctual and divided the year.

When did time begin?

In addition to marking various stages in the course of the year, human beings have recorded the passage of time by counting the years. In the widely used Gregorian calendar, the current year is counted from the birth of Christ. In Islam and Judaism this event is not considered so important. Most Muslim countries use the Islamic calendar, which began with Mohammed's flight from Mecca to Medina. In the Gregorian calendar this event took place on 16 July 622 AD. In Judaism, the years are counted from the creation of the world. According to the Jewish faith this occurred on 7 October 3761 BC (according to the Gregorian calendar). As a result, in Israel the year 2007 is regarded as being 5767 or 5768.

Not all calendar systems are as old as the Jewish, Christian and Islamic systems. The Taiwanese system, for example, is very young. Their years are counted from our year 1912, which is when the Republic of Taiwan was founded.

How do we know when events occurred in the ancient world?

Since people at the time couldn't have known of the birth of Christ prior to the event, they were also unable to call a year 500 BC. Dates in texts are converted with the help of ancient calendar systems.

The Romans tended to name the years after their consuls' terms of office. Meso potamia also used periods of office to calculate the year, whereas the Greeks began counting with the first Olympic Games.

In order to calculate dates accurately, historians need to know when in antiquity a dating system became established. For example, the Greek system that was based on the Olympics did not start until the 4th century BC, although there had been Olympic Games since the 8th century BC.

Have there been cultures that were dominated by women?

Government has not always been the exclusive preserve of men, and in antiquity it was not unknown for women to become rulers - the most famous being Cleopatra. A woman coming to power was often achieved by a circuitous route, and was usually because she had been the wife or sister of a deceased male ruler.

Many historians now believe that matriarchies - societies in which women dominated men - are the stuff of legend. Nevertheless some matrilineal agricultural societies do exist today, such as the Jaintia in India and the Mosuo in China. The principal characteristic of these kinds of matriarchies is that descent is traced through the mother. Men live in their mothers' houses and may move in with a sister later on. It is men who look after the children and perform the more arduous work. Reproduction is organised through marriages in which men are mere visitors - they are permitted to have sexual relations with women at night, but must leave at dawn.

How old is fashion?

Humans are the only animals that wear clothes, and clothing existed as early as the Palaeolithic period. Although no remains of clothes from that period have been found, tools that are thought to have been used for working on furs have been found. Fashion sense may have developed very early in human history. Perhaps someone in a tribe wore a loincloth that was more attractive than the others, and so his loincloth design was copied by other members of the tribe.

When did people first begin to wear jewellery?

It is thought that human beings have been adorning themselves for over 100 000 years. Shells, ivory, bones and animal teeth have all been used to make jewellery. However, beauty may not have been the only motive, since jewellery may also have had magical significance. Some historians suggest that humans had jewellery before they began to wear clothes. This is based on observations of primitive peoples, some of whom do not have clothing, although all wear jewellery. Jewellery has also been buried with people from very early times, presumably in the hope that the deceased would not find him- or herself short of anything in the hereafter.

Seeing inside the body

The revolution in medical imaging began shortly before the turn of the century. Towards the end of 1895, all the newspapers reported on mysterious X-rays which were making it possible to see through bodies. As proof, photographs were shown of a shadowy hand with clearly visible bones. So revolutionary was the discovery of this previously unknown radiation that Wilhelm Conrad Röntgen was awarded the first Nobel Prize for Physics six years later. For the first time in the history of humankind it was possible to look deep inside a human being without having to open him or her up first. Nowadays, doctors have a range of modern tools and techniques, from ultrasound and ECG to magnetic resonance imaging and the measurement of brainwaves. Nevertheless, X-rays are still the standard tool since they are both simple and effective to use.

How did Röntgen know that invisible radiation existed?

X-rays are electromagnetic waves just like light rays or radio waves. They differ only in that they have extremely short wavelengths, or very high frequencies. They are formed when electrons are excited and diverted by energy pulses as they orbit atomic nuclei and then fall back into their old orbit. The physicist Wilhelm Conrad Röntgen-who became a university professor in Würzburg at the age of 30-was just one of many scientists who were studying electric currents in evacuated glass tubes at the time. Inside these cathode ray tubes, electrons travel between two electrodes when a high current is passed between them. Most television receivers are based on this principle, even today. Röntgen discovered more or less by accident that the unknown radiation escaped during this process. Some sources mention a fluoroscope that was some distance away and lit up, even though electrons can only travel a few centimetres through air. Other accounts report that photographic paper in a drawer was accidentally exposed. Whatever it was that actually occurred, Röntgen recognised the importance of these phenomena and verified his assumption through a series of exhaustive tests. He was eventually able to capture the effect on photographic paper, which is how one of the first X-rays taken happened to be of his wife's hand.

What modern methods allow us to see inside the body?

Physicians now have three ways of looking inside a body: they can guide long endoscopes fitted with cameras deep into the body; place measuring instruments such as an ultrasound head onto the skin; or they can take readings without making any physical contact at all by using electromagnetic radiation or fields. These processes can also be distinguished by the method they use. Some pick up electrical signals from certain types of cells, such as the heartbeat or brainwaves. Others are imaging procedures, supplying an image directly through a camera or providing an indirect image of a tissue's make-up. X-rays show bones, but barely any muscle tissue because bone tissue is considerably denser and more difficult for the radiation to penetrate. Ultrasound investigation (or sonography), on the other hand, uses a transducer to send out sound waves and then picks up their echo. Gas or dense tissue inside the body returns a more powerful reflection than liquids such as blood.

What are the procedures that examine patients inside a tube?

The best known of these procedures - computer tomography (CT) - uses X-rays. An emitter is rotated around a patient who is lying inside a tube, producing a three dimensional X-ray. Magnetic resonance imaging (MRI), or nuclear spin tomography, also involves a patient lying inside a tube, although this method uses magnetic fields rather than radiation. It exploits the fact that the atomic nuclei of hydrogen in the body rotate slightly and behave like a kind of magnetic spinning top. To put it simply, the atoms are repeatedly lined up in a magnetic field and then disturbed. During this process the nuclei give off very weak radio signals which vary according to the type of tissue being examined. Giving the patient a contrast agent-such as barium meal in the case of an X-ray - can improve the images produced by all of these processes.

Nuclear medicine imaging techniques use radioactive tracer isotopes. Positron emission tomography (PET) is based entirely on them, using short-lived radioactive tracer isotopes which the body metabolises and absorbs into its cells. The isotopes emit positrons as they decay, and these can then be measured. PET scans are most often used to detect tumours.

How is it possible to measure brainwaves externally? 

The brain processes information chemically and electrically. The electric potential and the impulses that run along nerve cells can be measured from outside the body. As early as 1924, Professor Hans Berger from Jena, Germany, discovered that the electrical activity of the cerebral cortex can be measured externally if electrodes are placed on the head in a particular arrangement. An electro encephalogram (EEG) shows rhythmic oscillations from which it is possible to determine whether, for example, a person is in a particular phase of sleep, or whether he or she is relaxed, excited or in a state of deep concentration. More specific brain activity can be investigated with the help of imaging procedures. It is even possible to observe the brain as it thinks, because functional MRI and PET reveal which areas of the brain are active at any particular time.

The greatest detail is obtained from the most recently developed method - magneto encephalography (MEG). This can even reveal the activity of individual groups of nerve cells with accuracies in the order of a few millimetres and milliseconds.

Leonard da Vinci - a genius without parallel

It is only every couple of centuries that humanity is graced with a genius who makes important inventions and discoveries in several fields at once. Such a genius was Leonardo da Vinci. He was born the son of a notary and a peasant girl on 15 April 1452. Denied a university education because of his illegitimate birth, he was apprenticed to the Florentine artist Andrea del Verocchio in 1465. Leonardo never seems to have forgotten that he was excluded from university and for the rest of his life despised academia and valued the individual mind above all else.

What was so special about Leonardo?

Leonardo's interests and talents were unusually wide-ranging and there were many fields in which he was a pioneer. Although anatomy formed part of every artist's basic training in the Renaissance, it was Leonardo who most frequently applied the insights he gained from anatomy. He was constantly at work deepening his understanding of the subject and produced thousands of anatomical drawings of humans and animals.

Leonardo is most famous as an artist, but he promoted himself as an engineer, most famously with his numerous ingenious 'machines of war'.

Was Leonardo an engineer?

It was far from self-evident at the time. that Leonardo's interest in engineering would meet with a wider response. It was only during his era - the Renaissance - that a deep hostility to experimentation began to subside. Plato- one of the great philosophers of antiquity, who had been revered since the heyday of scholasticism at the beginning of the 13th century eschewed experiments and sought understanding through reason alone. For him, experimentation was a 'base. mechanical art'. However, manuscripts written by other thinkers of Greek antiquity emerged during the Renaissance-manu scripts concerning subjects such as mining, agriculture, architecture and astronomy. But since very few people were able to read Greek, it was a long time before these works were brought to the attention of the broader public.

With this background in mind, it is easy to see why, when Leonardo went to Milan in 1482, it was not because the court was expecting him to work as an engineer. To begin with, Leonardo had to make a living from his painting, and in this period he created the famous Virgin of the Rocks and Lady with an Ermine.

Leonardo's great opportunity to demonstrate his engineering prowess came in another artistic endeavour, when he was given the task of designing a sumptuous stage set for the court in Milan. On the occasion of the Paradise Festival on 13th January 1490, a huge model of the planets orbiting through their astrological signs was presented. Regrettably, none of Leonardo's records for this project remain - we only know about it because the name Leonardo was on everyone's lips after the festival.

Between 1490 and 1500 Leonardo was at the peak of his fame. He was also finally in demand as an engineer, and received commissions to produce works to improve the waterways of Lombardy as well as to develop weapons and fortification technology. However, this period also saw the creation of one of Leonardo's major works of art, The Last Supper, which took him four years to complete.

What were later scientists able to learn from Leonardo?

Leonardo evidently had time to spare, even when involved in his most elaborate commissions. From about the middle of the 1480s he kept notebooks in which he wrote his thoughts on scientific and engineering matters. These included physio logy, anatomy, optics, acoustics, the design of musical instruments and, as always, weapons technology and automation. He was obsessed by automata, which is quite surprising given that in his day practically nothing was automated. Leonardo developed a tank and a car that drove themselves, and also pondered the problems of flight, studying the anatomy of birds and their ability to fly. Subsequent to these studies he developed-on paper only a helicopter and a parachute. Some of these ideas, including Leonardo's parachute and a self-propelled car, have been realised by modern-day researchers. The parachute actually worked and the car is remarkably similar to modern motorised vehicles.

Towards the end of the 15th century Ludovico Sforza, Leonardo's chief employer, became involved in armed conflicts with France. He was captured, and so Leonardo's time in Milan came to an end. For 20 years he spent periods of time in Florence, Rome, back in Milan and towards the end of his life he went to France, where he died on 2 May 1519. Over the centuries, his work was scattered and lost so that many of his groundbreaking ideas on optics and aeronautics had to be developed all over again centuries later.

Nuclear fusion, power for the future

Scientists around the world are looking for new sources of energy, and for the last 50 years physicists have been putting their hopes in nuclear fusion. Fusing hydrogen atoms produces the inert gas helium and at the same time huge amounts of energy are released. This is the theory, at least, although so far no working machine has been produced. Nevertheless, nuclear fusion has great potential. Just 1 kg of hydrogen fused into helium could produce as much energy as burning about 11 000 kg of coal.

Do fusion reactors re-create the Sun?

The Sun is the model for terrestrial nuclear fusion reactors. For billions of years, light hydrogen nuclei in the Sun have been fusing into helium. The energy radiated by the Sun in a single second is 100 million times as much as the energy used by the entire population of the Earth in a year. The fusion process works so well there because of the immense pressure and a temperature of 15 million °C in the Sun's core.

Before the atomic nuclei fuse, they separate from their surrounding electrons and form a plasma made up of charged particles. Every second, the fusion reactor that is the Sun fuses around 564 million tonnes of hydrogen into about 560 millions tonnes of helium. The difference in mass is converted into energy,

The best current fusion reaction experiments are also based on hot plasma.

Although the largest existing test reactor consists of a plasma chamber measuring 80 m³, less than 1 g of hydrogen is actually involved. Temperatures of 100 million "C are needed to initiate fusion, and micro waves are used to heat the gas made up of hydrogen atoms. Despite the heat, the only time nuclear fusion was successfully initiated for just a few seconds was in 1997 at the European Jet (Joint European Torus) fusion experiment in Culham, UK - and the scientists celebrated this as a great success. The process used up 25 MW of energy and only yielded 16 MW in return. Nevertheless the construction of the next reactor-ITER (International Thermonuclear Experimental Reactor) - which will be about 10 times larger, was approved in 2006 and will be built in Cadarache, France. In about 10 years' time it is hoped that this machine will for the first time release more energy than it uses.

In what way do fusion reactors differ from today's nuclear power stations? 

In a conventional nuclear power plant, heavy atoms are split in a process called nuclear fission, whereas in a fusion reactor light atoms are joined. For a nuclear power station to have a controlled chain reaction, the radioactive fuel uranium- a very heavy metal-is required. Nuclear fusion, on the other hand, uses hydrogen, the lightest of all elements. Both processes convert mass into energy-just as described by Einstein's famous formula E = mc² (E= energy, m = mass, c = the speed of light). Since nuclear fusion converts relatively more mass, the energy yield should in theory be greater.

Why are such powerful magnetic fields needed?

One of the greatest challenges facing nuclear fission is the ability to control the chain reactions. Once a reaction has started and there is sufficient fuel available, it keeps going. The atomic bomb is the most frightening example of this kind of reaction. Nuclear fusion, with its hot hydrogen plasma, is much harder to ignite. Furthermore, slight temperature and pressure fluctuations are sufficient to extinguish the solar fire. Extremely strong magnetic fields are required to control and contain the plasma, since no material can withstand the 100 million "C temperature of the hot cloud of plasma. In order to avoid any contact with metals or ceramics, the magnetic fields hold the plasma's hydrogen nuclei in place as if with invisible threads.

Is nuclear fusion dangerous?

Extreme temperatures, strong magnetic fields and the large amounts of energy being released can be quite frightening, although scientists are convinced that fusion reactors are safe. This is because an independent chain reaction-of the type that occurs in a traditional nuclear (fission) reactor - would be impossible. If the magnetic fields or the microwave heat source fail, the whole fusion process stops immediately. In principle. incidents like meltdowns cannot happen.

However satisfactory that sounds, a fusion reactor can't function entirely without radioactivity. The fuel- the heavy hydrogen isotope tritium-and the chamber walls that are bombarded with rapidly moving particles during fusion both emit radiation. However, far less is emitted than is emitted from the spent fuel rods or the reactor vessel of a fission power plant. The worst possible accident would be a leak in the water cooling system. Even if tritium were to escape from the reactor, the radioactive dose released would be around one-tenth that of the natural annual dose received from cosmic rays. Even the contaminated building components that are replaced annually do not really qualify as long-term nuclear waste. They will only need to be stored for about 100 years in order to be rendered harmless.

When is the first fusion plant due to go into operation?

Although the advantages of a fusion reactor are obvious, it will be several decades before a plant can start to provide power to the grid. JET will be succeeded by ITER which is 10 times larger. However, even if ITER were to prove successful in about 10 years' time, this vastly expensive project would still not produce a single kWh of electricity. It will only demonstrate that commercial power generation by means of nuclear fusion is possible in principle - which is something nobody is able to say with certainty at the moment. Nevertheless, the next project is already being planned. DEMO will be at least twice the size of ITER, and it may actually produce electricity. However, construction is not due to start for at least another 20 years.

Bionics - inventions inspired by nature

Bionics deals in the observation, analysis and understanding of natural processes and their use in novel engineering designs. This is not an attempt to copy nature, but an effort to understand its principles and use them in technological applications.

Where does the term 'bionics' come from?

The word bionics is a combination of biology and electronics, and was first suggested by American air force major Jack E Steele in 1960.

Who was the inventor of bionics? 

Leonardo da Vinci, the great Italian artist and engineer, is often put forward as the first student of bionics. This universal genius studied many natural phenomena, such as bird flight, in the early 16th century. On the basis of his observations, he produced novel engineering designs that included flying machines, and even a helicopter.

Is the parachute modelled on nature?

It was more than 500 years ago that Leonardo da Vinci sketched the first parachute, possibly receiving his inspiration from dandelion seeds, whose umbrellas of tiny hairs carry them for hundreds of metres on even the slightest breeze. Perhaps the first trial of a parachute occured nearly 400 years ago when, in 1617, Croatian Faust Vrancic performed the first successful parachute jump and descended safely from the bell tower of St Martin's Cathedral in Bratislava.

What was Otto Lilienthal's contribution to the development of aeroplanes?

Like many other pioneers of aviation around the world such as the Australian Lawrence Hargrave- the German Otto Lilienthal was an early proponent of bionics. He observed and studied storks, analysing the way in which the birds fly. Based on what he observed, he developed and built unpowered flying machines. Lilienthal is credited with the world's first manned unpowered flights, gliding for distances of up to 230 m in the early 1890s. He was killed in 1896 when one of his gliders crashed on a windy day.

Are there any flipper-driven ships?

A system for flipper propulsion - based on the way in which penguins swim- is currently being developed. Preliminary tests have shown that this kind of system is more effective, and provides more responsive manoeuvring, than a traditional propeller. However, before the idea can progress from the drawing board to a working model, some means will have to be perfected for reliably translating the circular motion of the drive shaft into the up and down movements of the flippers.

How can an earthworm contribute to an investigation of the human intestine?

German researchers have been studying the way in which earthworms move, and have used their observations for the development of a novel device for performing colonoscopies - looking inside the colon. Unlike the conventional tools for this and similar jobs, which are pushed along from the outside, this revolutionary new microrobot moves independently through the intestine, minimising the risk of injury.

What was the model for Velcro?

Velcro is another invention modelled on nature. In the mid-20th century, the Swiss scientist Georges de Mestral considered the irritating way in which burrs are able to stick to the surface of fabric, making them hard to remove. He examined the burrs under the microscope and developed a similar synthetic fastening mechanism.

Is it possible to dive underwater without getting wet?

The fishing spider manages to stay dry when it dives underwater. Fine hairs on the surface of its body trap innumerable tiny air bubbles so that its entire body is protected by a layer of air. Bionic engineers are trying to adapt this principle for technical applications, such as coatings for bathing suits or the hulls of ships.

What lessons can structural engineers learn from nature?

Constructing buildings that are delicate yet robust is one of the challenges facing architects today. Spiders provide nature's model for elegant roof structures, like that built over Munich's Olympia Park. Spider webs are braced by crossing gossamer threads which can withstand enormous forces. Attempts are even being made to reproduce spiders' silk-which is extremely light but also very strong-in the laboratory.

Which natural example could be useful in developing robots to explore Mars?

The first robot explorers on Mars rolled around the stony surface of our neighbouring planet on six wheels, but the next generation could be equipped with six insect-like legs, which would help them to overcome even quite large obstacles. Experiments with cockroaches have demonstrated that each leg performs every step fully independently. The development of the first walking robots is founded on this principle.

Can lens manufacturers learn from the eye?

Sophisticated lenses, compound eyes and optical fibres - no other natural sense has inspired such a wide range of innovative designs as the sense of sight. Prototypes of liquid lenses are already being developed, and Japanese scientists have constructed a system made up of many tiny lenses similar to those found in the compound eyes of flies and have placed them on a hemisphere to provide a 360° view. An X-ray sensor on the International Space Station is able to obtain an extremely wide-angled view because it is domed like the eye of a lobster.

Are computers imitating the brain's structure? 

There is no computer as powerful as the human brain. The reason lies in the way that brain cells are packed into a tight network. Inspired by this structure, computer scientists have been able to build small, synthetic neural networks using electronic components. These are able to learn certain facts on the basis of training examples, without first having to be programmed.

Could the solution to the energy problem lie in synthetic photosynthesis?

No solar cell is as efficient at transforming sunlight into a different form of energy as photosynthesis is for plants. Scientists have been trying to copy this process for years. In one approach a German-Swiss team have had some initial success with a system of self-organising macro molecules and lipid membranes, which was able to store the energy from sunlight with separate electrical charges. However, this early development is not yet suitable for use in a rechargeable solar battery because so far the electric charges could only be accessed once.

Will the structure of a gecko's foot provide the model for new adhesives?

Geckos can walk safely up the smoothest of vertical surfaces, thanks to tiny hairs on their feet (see p. 173). Scientists in the USA have now been able to copy this adhesive effect using carbon nanotubes. Early experiments demonstrated that the nanotubes had ant adhesive force stronger than all traditional adhesives, and could even provide better adhesion than that achieved by geckos' feet. Although the synthetic gecko modules have tremendous adhesive properties, they won't have a real-world application until the problem of how to unstick them has been solved.

What can engineers learn from sharks?

Sharks can swim very long distances with the expenditure of very little energy. One of the reasons for this is their special skin, which is not smooth but covered with numerous fine structures which help to reduce its flow resistance to water. Already swimsuits are available which make use of similar microstructures, and experiments are being conducted to produce coatings for the hulls of ships that will help to reduce their fuel consumption.