What are sauropods?

Sauropods were a group of dinosaurs that were all built to the same general design. They all had a short barrel-shaped body to accommodate the huge gut needed to digest their vegetable diet, a very long neck and tail, a comparatively tiny head and peg-like teeth for grazing. The other important feature of the sauropods is that they were all enormous. They were extremely heavy, and because they lived in large herds they churned up the ground as they move about. It is still possible to see the damage caused by their movements in the ancient rock layers were fossils of the sauropods were found.

The long neck of the sauropods is thought to be an adaptation to help animals feed on tall trees, like the modern giraffe. The whole structure of the dinosaurs is a very clever piece of engineering, because their long neck, which was usually held out horizontally, was balanced by the weight of the tail. The vertebrae were shaped to allow the attachment of powerful muscles and rope-like tendons and ligaments, which held the whole structure together like a suspension bridge. Despite the great length of the neck and tail, they were not a flexible as we might think. They were usually stretched out almost in a straight line.

Is sex necessary?

Is sex really necessary in our everyday life? What are the health benefits of sex?


Improved sense of smell

After sex, production of the hormone prolactin surges. This in turn causes stem cells in the brain to develop new neurons in the brain's olfactory bulb, its smell center.

Reduced risk of heart disease

In a 2001 follow-up to the Queens University study mentioned above, researchers focused on cardiovascular health. Their finding? That by having sex three or more times a week, men reduced their risk of heart attack or stroke by half. In reporting these results, the co-author of the study, Shah Ebrahim, Ph.D., displayed the well-loved British gift for understatement: "The relationship found between frequency of sexual intercourse and mortality is of considerable public interest."

Weight loss, overall fitness

Sex, if nothing else, is exercise. A vigorous bout burns some 200 calories--about the same as running 15 minutes on a treadmill or playing a spirited game of squash. The pulse rate, in a person aroused, rises from about 70 beats per minute to 150, the same as that of an athlete putting forth maximum effort. British researchers have determined that the equivalent of six Big Macs can be worked off by having sex three times a week for a year. Muscular contractions during intercourse work the pelvis, thighs, buttocks, arms, neck and thorax. Sex also boosts production of testosterone, which leads to stronger bones and muscles. Men's Health magazine has gone so far as to call the bed the single greatest piece of exercise equipment ever invented.

Reduced depression

Such was the implication of a 2002 study of 293 women. American psychologist Gordon Gallup reported that sexually active participants whose male partners did not use condoms were less subject to depression than those whose partners did. One theory of causality: Prostoglandin, a hormone found only in semen, may be absorbed in the female genital tract, thus modulating female hormones.

Pain relief

Immediately before orgasm, levels of the hormone oxytocin surge to five times their normal level. This in turn releases endorphins, which alleviate the pain of everything from headache to arthritis to even migraines. In women, sex also prompts production of estrogen, which can reduce the pain of PMS.

Less-frequent colds and flu

Wilkes University in Pennsylvania says individuals who have sex once or twice a week show 30% higher levels of an antibody called immunoglobulin A, which is known to boost the immune system.

Better bladder control

Ever hear of Kegel exercises? You do them, whether you know it or not, every time you stem your flow of urine. The same set of muscles is worked during sex.

Better teeth

Seminal plasma contains zinc, calcium and other minerals shown to retard tooth decay. Since this is a family Web site, we will omit discussion of the mineral delivery system. Suffice it to say that it could be a far richer, more complex and more satisfying experience than squeezing a tube of Crest--even Tartar Control Crest. Researchers have noted, parenthetically, that sexual etiquette usually demands the brushing of one's teeth before and/or after intimacy, which, by itself, would help promote better oral hygiene.

A happier prostate?

Some urologists believe they see a relationship between infrequency of ejaculation and cancer of the prostate. The causal argument goes like this: To produce seminal fluid, the prostate and the seminal vesicles take such substances from the blood as zinc, citric acid and potassium, then concentrate them up to 600 times. Any carcinogens present in the blood likewise would be concentrated. Rather than have concentrated carcinogens hanging around causing trouble, it's better to evict them. Regular old sex could do the job. But if the flushing of the prostate were your only objective, masturbation might be a better way to go, especially for the nonmonogamous male. Having sex with multiple partners can, all by itself, raise a man's risk of cancer by up to 40%. That's because he runs an increased risk of contracting sexual infections. So, if you want all the purported benefits of flushing with none of the attendant risk, go digital. A study recently published by the British Journal of Urology International asserts that men in their 20s can reduce by a third their chance of getting prostate cancer by ejaculating more than five times a week.

What are tectonic plates?

The Earth's crust is made up of about 30 huge plates that float on the semi-liquid mantle surrounding the earth's core. There are currents and movements in the mantle, so these plates move very slowly in relation to each other - about 10 cm per year on average. The floor of the Pacific Ocean is one enormous plate. Some of the plates carrying continents also carry parts of the ocean floor. The thickness of the plates varies from 8 km to 200 km.

Earthquakes are evidence of movement of the tectonic plates that carry the continents. Most of the areas where earthquakes take place are along the edges of the plates. Friction holds the plate edges together for a while, but continuing movement means that huge stresses built up. The tension is suddenly released when the plates shift sharply and this causes earthquakes. There are other causes of earthquakes, but they all involve sudden movement of the crust along a fault or crack. The energy released in an earthquake is enormous - as much as 10,000 times the power released by the world's first atomic bomb.

What are explosives?

Explosives are substances that release a very large amount of energy in a short time when they burn. They all contain a fuel plus an oxidizer, which is a substance containing sufficient oxygen to burn the fuel. Explosives do not need air to explode, because they contain their own oxygen, and so they can burn in confined spaces or even underwater. Some explosives, such as those in a cartridge detonator, explode violently when hit or heated. Others only cause a violent explosion when confined in a gun barrel or a hole drilled in rock for blasting.

Gunpowder, the first ever explosive, was invented in China over 1,000 years ago. Large amounts of modern explosives are commonly used in quarrying and mining, as well as for munitions.

What is health?

Being healthy involves far more than simply not being ill. If you feel you're in good health, your organs will be working properly and you will have the energy to live life to the full. This feeling of wellbeing affects your mind and your body.

The environment you live in, your diet and your lifestyles affect your health. Physical fitness is an important part of health, and this means that your heart, lungs, skeleton and muscles all work together smoothly to carry out your daily activities. Fitness involves strength, stamina and suppleness, and you need regular exercise to maintain all these conditions. Careful exercise develops a healthy heart and lungs, and gives you the strength and stamina that allow you to run, cycle and swim. A sensible diet and sufficient sleep also help you to keep healthy.

Air pollution is an environmental factor that can damage health. Exhaust fumes from motor vehicles contain substances that can cause asthma and other breathing problems. In hot climates, smog can also develop, trapping these air pollutants and making the health risk greater.

Many diseases are infections that are caused by bacteria or virus. Other illnesses are caused by failure of some of the body's organs or tissues. Sometimes part of the body wear out or are not replaced properly, but most health problems are caused when the body simply fails to maintain itself. Joints can wear out, causing arthritis, or the digestive system may not work as efficiently, causing various types of stomach upsets. Other diseases may be caused by a person's own lifestyle, for example lack of exercise or poor eating habits. Smoking is now known to be a contributory factor in many diseases.

What are Hormones?

Hormones are chemical messengers that are produced in one part of the body and have an effect on another part.

Hormones switch body processes on and off, and they regulate most of the body's activity. The nervous system also helps in these processes, giving pared instructions along the nerves. The body's endocrine system uses hormones which work much more slowly. The majority of hormones are carried around the body in the bloodstream, reaching all the major organs and tissues.

The body has more than 30 different hormones. They are mostly produced in organs called endocrine glands.

These glands discharge the hormones directly into the bloodstream. Other types of glands pass their secretions through ducts to the point where they are needed. Endocrine glands are found in the head, neck and torso. The amount of hormones in the body is regulated by a feedback system. This means that once hormones are produced, the body measures them and once they have reached the required level, their production is switched off again. Sometimes this mechanism does not work properly and over or underactive glands such as the thyroid can produce illness.

What is electricity?

Electricity powers our lights, heating, electronic appliances such as computers and television, and a host of other essential services that we take for granted. However, electricity has much more important aspects because it is the force that holds together the molecules and atoms of all substances.

The type of electricity that is most familiar to us is electrical current. This is the flow of electrical charges through a substance called a conductor, such as a metal wire. This flow happens because some of the negatively charged electrons circling the nuclei of the conductor's atoms are held loosely. The electrons can move from one atom to the next, producing an electrical current.

Energy can no be created. An electrical generator is simply a means of converting mechanical energy into electrical energy. In its simplest form, a generator spins coils of wire in a magnetic field, causing the flow of electrical current in the conducting wire. The power to spin the generator comes from other forms of energy. This energy might be stored energy in fossil fuels such as coal or oil, hydroelectric power from dams, wind power from turning huge windmills, or nuclear power produced by the radioactive decay of elements. In all these cases, one form of energy is simply converted into electrical energy.

What is a comet?

Comets are often described as "dirty snowballs". The solid center, or nucleus, of a comet consists mostly of ice mixed with sooty material. The nucleus is quite small and is usually only a few kilometers across

Comets travel around the Sun in an elongated orbit. They plunged out into deep space beyond the farthest planet before diving back into the solar system and passing close to the Sun. As the comet's nucleus comes closer to the Sun, it becomes smaller and may eventually break up into small fragments. Comets are thought to be as old as the solar system itself.

You can not see the nucleus of a comet with the naked eye, but you can sometimes see its tail. It appears as a smear of light that moves very gradually across the sky. As a comet moves closer to the Sun, the ice and other frozen gases in its nucleus begin to boil off, producing a long tail of gas and dust. The tail always point away from the Sun because light and other forms of radiation from the Sun push against the minute particles that are present within the tail.

What is the appendix for?

The appendix is probably a leftover from our very ancient ancestors, and in humans it has very little use. In animals that eat a lot of plant material, such as rabbits, the appendix is large and contains bacteria that helps digestion. The human appendix is a tiny finger-like projection from the lower part of the gut. It sometimes become inflamed and has to be remove surgically.

Who were our first ancestors?

Humans belong to a group of mammals called primates. It includes apes, monkeys and several much smaller animals such as lemurs and bush babies. As much as 50 million years ago, back in the Eocene Period, there were traces of primate-like animals. They were small and looked rather like squirrels, but their eyes faced forwards like modern monkeys and they had grasping hands and feet.

These animals evolved into monkey-like animals, but remains of primates are scarce and the fossil record contains many gaps. Those few remains that have been found are of tree-living monkeys that are very similar to monkeys living today.

The early ancestors of humans were called hominids, and they appear to have evolved in Africa where many of their remains have been discovered.

The earliest remains that were probably our ancestors are those of human-like apes called Australopithecus, which date back more than three million years. These creatures walked erect and looked similar to us, but their brain capacity was small. Several forms of Australopithecus heve been found. All of them were much shorter than modern humans, and their teeth show that they have a vegetarian diet.

The first true humans appeared around two million years ago in Africa. It has been named Homo habilis (handy man) because it used primitive stone tools. It was still rather ape-like, however, and was soon replaced by Homo erectus, which looked very much like us. It had a much heavier jaw, bony ridges over the eyes and a sloped-back forehead. Homo erectus appeared about 1.6 million years ago. Only a few incomplete fossils of these early humans have been found, but their tools have been discovered in large numbers.

Earth's Map

The earliest known maps were made in Babylon on clay tablets, as long ago as 2300 BC. Some Egyptian drawings and paintings found in tombs are almost as old. The Greek mathematician Ptolemy (AD 90-168) produced an enormous eight-volume guide to geography and map-making called The Guide to Geography. It was followed carefully by map-makers for almost 1,000 years.

It is not possible to draw the curved surface of the globe accurately on a flat sheet of paper. This problem puzzled mapmakers for many years. In 1569, Gerardus Mercator showed how to convert the rounded shape of the world into a cylindrical shape, which could be unrolled to make a flat map. However, this can distort the size of countries in the far north and south. Dividing the earth into "orange peel" segments gives a truer image of the size of countries.

What are perestroika and glasnost?

In the Soviet Union, the Communist Party controlled almost every aspect of people's lives. However, in the 1980's Soviet people were aware that their standard of living was slipping far behind that of the West. When Mikhail Gorbachev become party leader in 1985, he begun a process called perestroika, or restructuring. Some political activities were allowed, and economical reforms enabled people to run their own businesses. Gorbachev's policy of glasnost, or openness, allowed people to express themselves freely.

Gorbachev became Soviet president in 1990, but was thrown out in a coup the following year. He returns to power to ban the activities of the Communist Party. The Soviet Union swiftly fell apart, breaking up into its original 11 republics in 1991.

Who was Napoleon Bonaparte?

Napoleon Bonaparte was born on the French island of Corsica. He became a great general in the French army and achieved several military successes. After an unsuccessful campaign against the British in Egypt, Napoleon returned to France in 1799 and took complete control of the country with the backing of the Army.

Napoleon ruled France for 15 years, and in 1804 he crowned himself emperor. He governed effectively, and increased the power of the French army enormously by setting up a system of conscription. It meant that every adult Frenchman had to do military service for a time.

Napoleon had created a massive army, which he used to try and conquer Europe. The French armies conquered huge land territories including Austria and part of Russia, and proposed to invade Britain. Napoleon’s navy was finally defeated by Admiral Nelson at the Battle of Trafalgar, however, and the invasion never took place. Instead Napoleon turned his attention to Spain and Portugal, which were given the support of Britain in their wars against the French.

What led to the Great War?

Continual trouble in the Balkans led to the formation of several complicated military alliances throughout Europe. The continent was eventually split into two groups. Britain, France, and later Russia joined to form the Entente Cordiale; Germany, Austri-Hungary and Italy formed the Triple Alliance. In 1914 Archduke Franz Ferdinand of Austria-Hungary was assassinated in Serbia, activating the alliance agreements. First Austria declared war on Serbia, Russia sided with Serbia, and then Germany declared war on Russia. Germany invaded Belgium, bringing the British and French into the conflict. The British, French and Russians became known as the Allies, while their opponents were the Central Powers.

World War I, or the Great War, was the first mechanized war in history. In the beginning, the fighting was similar to wars fought during the previous century. Mounted cavalry charged enemy lines but were cut down by fire from the recently developed machine guns. No modern tactics had been developed to handle the battles between armies spread across whole countries.

The battlefields became deadlocked, with few advances. The troops dug deep trenches. About 10 million men died in battles, which usually gained an advance of about one kilometer. Another 20 million men were wounded.

What are the Dead Sea Scrolls?

The Dead Sea Scrolls are religious writings that were first discovered in 1947, hidden in caves near the Dead Sea. The dry atmosphere of the caves had the effect of preserving the scrolls. About 800 scrolls have been found, mostly in a place called Qumbran in Israel. They date from between 150 BC and AD 68. They include all of the books of the Old Testament oe Hebrew Bible except for Esther.

Scholars believed that the scrolls were concealed by members of a religious sect called the Essenes, who lived in isolated community. They hid the scrolls to keep them safe during political unrest in the area, where they remained hidden for hundreds of years.

What is evolution?

Evolution is the name given to the gradual adaptation of living things to take advantage of the environment they live in.

This process, which takes place over millions of years, can mean that both animals and plants can change their appearance, size and habits, and eventually become new species.

We can see how evolution has changed living things by examining fossils. Fossils preserve the body parts of living creatures from long ago so that we can see how they have changed over millions of years. Sometimes the changes are very gradual, while others seem to have taken place quite rapidly. It is often possible to find a series of fossils, with each one showing a gradual change. This can tell us how a creature has altered due to the process of evolution. For example, scientists have traced the evolution of the horse from a tiny ancestor with normal toes to the large-hoofed animal we see today.