It would be easy to think that a duck’s feathers would soon become waterlogged so that it would sink, but in fact, ducks, geese and swans, as well as seabirds, have waterproof feathers, which enable them to swim and dive beneath the surface of the water. Ducks create this waterproofing using the oil from the preen gland, near the base of the tail, which they spread through their feathers...

Dinosaurs lived for an enormously long time-some 150 million years – before they died out about 64 million years ago. All the dinosaurs disappeared at about the same time. However, whether this happened over a few days, a few years, one or two centuries, or even a few thousand years is impossible to say. Many people believe that the dinosaurs became extinct as a result of climate change after...

Several families of birds can be trained to ‘talk’, but in reality they are simply mimicking noises without really understanding what they are saying, although they can be taught to associate a given word or phrase with a given action, for example saying ‘give us a peanut’ to get a reward. The best talkers are parrots and mynas, and members of the crow family such as crows, jackdaws...

Construction of the famous white marble bell tower (campanile) of Pisa’s cathedral began in 1173 but by the time three stories were built, it had already begun to lean. Over the centuries, many methods have been tried to prevent the lean getting worse but as most people did not understand what was causing the lean, they made it worse. The soil under the tower is very soft and waterlogged...

The simplest way to describe an optical illusion is that it is a ‘trick’ that our eyes play on us. We seem to see something that isn’t really so. Or we may be able to see the same object in two completely different ways. If our eyes are working properly, and they are instructions for seeing exactly what is before us, how can they play such tricks on us? This is because vision is not...

We all dream at night, although we may not remember our dreams in the morning. Although scientists do not precisely understand how we dream, they have discovered that it is important for us to do so and people who are prevented from dreaming soon begin to feel unhappy. We are deeply asleep when we dream, but our brains are active. Scientists think that our brains may be working though...

If this question had a simple answer, such as a formula that could be learned, you can be sure that every comedian would know it! But laughter is a complicated things, and the best explanations of it are still only theories. We know, of course, that laughter is an expression of many feelings and that laughter is only found among human beings. It is difficult to decide what really makes...

Early man had to rely on his own muscle-power to carry objects, but over thousands of years tamed animals, such as horses, oxen and donkeys, elephants and camels. In order to be able to transport more goods than an animal could carry on its back, sledges and hurdles that could be pulled behind the animal were eventually invented, as well as such instruments as ploughs to make agriculture...

There are more than 150 species of octopus, ranging from the very small to the giant octopus, which may reach 33ft (10m) in length. Most of them eat crabs, fish, crustaceans and smaller mollusks, which they catch and tear apart with their suckered tentacles. An octopus’ mouth is shaped like a parrot’s beak, with two very strong jaws. In addition the octopus can inject venom or poison...

Pearls, whether natural or cultured, are made in the bodies of some species of oysters and are composed of the same material as the iridescent mother of pearl that lines oysters’ shells, which is a form of calcium carbonate. If something, such as a grain of sand, gets into an oyster’s shell, it will not be able to expel it and instead coats it with layers of mother of pearl, creating...

Jazz is a form of music that originated in southern UNITED States in the late 19 th century, as a development of the songs and spirituals of Afro-American slaves, with melodies that incorporate both African and European music , It is a strongly rhythmic form of music, incorporating elements of ragtime, the blues and folk music. One popular early form came from New Orleans and was sometimes...

According to an ancient Greek myth, the god Pan invented the first musical instrument – the pipes that are named after him – after he accidentally breathed heavily through old reeds beside a river and produce a wail. He so liked the sound that he broke the reeds off and tied them together. Because the reeds were different lengths they produce different notes. Although this is a myth,...

The ability to make a ball swerve through the air rather than follow a straight line is a valuable one in many sports, whether as a pitcher in baseball, a spin bowler in cricket or a footballer taking a penalty. The curve occurs because of the ‘Bernoulli effect’, which was discovered by scientist Daniel Bernoulli. When the player wants to make the ball follow a curve through the air,...

Stars and Stripes - also called ‘Old Glory’, or ‘Star-spangled Banner’, is the flag of the United States of America. It consist of white stars (50 from July 4, 1960) on a blue background, with a field of 13 alternate stripes, 7 red and 6 white. The 50 stars stand for the 50 states of the Union, and the 13 stripes stand for the original 13 states that signed the Declaration of Independence....

The sundial was one of the earliest devices for measuring time. But it can work only on a day with plenty of sunlight. Early peoples also used ropes with knots tied at regular intervals. In the ninth century candles were marked with regularly spaced lines, but this was not very accurate as a draught could cause the candle to burn more quickly. When burned, such devices measured time....

If we think about different types of clocks and watches, we associate some of them with different countries: grandfather clocks and marine chronometers from England, cuckoo clocks from both Germany and Switzerland, precision-engineered jeweled watches from Switzerland, too, and digital watches from countries in south-east Asia such as Japan. Watches are very important to the Swiss economy...

Scorpion are distant relatives of spider, but while spiders bite, scorpion carry their venom in poison glands near the stinger that they carry at the tip of the tail. Many scorpions live in arid areas, such as deserts, where they will shelter from the heat of the day under stones or in the burrow of another animal, and hunt insects at night. Other species live in jungles and shelter...

Erosion constantly wears away solid rock through the action of rain, snow and waves, frost and ice, glaciers and wind and the bits broken off are slowly broken down into ever-smaller pieces. The most common mineral found in sand is quartz but  other mineral, such as calcite, feldspar and mica are also present. The colour of sand on a beach reflects the material from which it is...

Mussels are molluscs and are related to water snails. Because their shells are divided into two halves, they are called bivaldes. The shell protects the soft body of the animal. A powerful foot enables the animal to...

Parasites are animals that live at the expense of other animals. They rob the host animal of nourishment and often cause it to become sick. However, in other types of relationships, different animals can help one anothe...

Crustaceans are aquatic arthropods such as crabs, lobster and shrimps. They have a very tough, jointed external skeleton and jointed walking legs. Their body is divided into a region that contains most of the...

Arthropods are the animals with a hard external skeleton like a suit of armour. The skeleton is jointed to allow movement. Arthropods have evolved in a different way to vertebrates and even their blood is...

A marsupial is a mammal whose young are born in an extremely immature state. The newborn undergoes most of its development attached to one of its mother's nipples and nourished by her milk. Females of most...

A reptile is an air-breathing animal with a body structure comprising of traits from amphibians, birds and mammals. Reptiles are generally scaly and their eggs are fertilized internally. Living  reptiles include...

A warm-blooded animal is an animal that almost always has about the same body temperature, regardless  of the temperature of its surroundings. Birds and mammals, including human beings, are warm-blooded...

Mammals are vertebrate animals who nourish their young with milk. All mammals and birds are warm-blooded. Most mammals have hair on their bodies which moults to be...