Category Archives: Interesting Facts

Facts About Archimedes

  • Archimedes (c.287-212Bc) was one of the first great scientists. He created the sciences of mechanics and hydrostatics.
  • Archimedes was a Greek who lived in the city of Syracuse, Sicily. His relative, Hieron II, was king of Syracuse.
  • Archimedes’ screw is a simple pump supposedly invented by Archimedes. It scoops up water with a spiral device that turns inside a tube. It is still used in the Middle East.
  • To help defend Syracuse against Roman attackers in 215Bc, Archimedes invented many war machines. They included an awesome ‘claw’ — a giant grappling crane that could lift whole galleys from the water and sink them.
  • Archimedes was killed by Roman soldiers when collaborators let the Romans into Syracuse in 212Bc.
  • Archimedes analysed levers mathematically. He showed that the load you can move with a particular effort is in exact proportion to its distance from the fulcrum.
  • Archimedes discovered that objects float because they are thrust upwards by the water.
  • Archimedes’ principle shows that the upthrust on a floating object is equal to the weight of the water that the object pushes out of the way.
  • Archimedes realized he could work out the density, or specific gravity, of an object by comparing the object’s weight to the weight of water it pushes out of a jar when completely submerged.
  • Archimedes used specific gravity to prove a sly goldsmith had not made King Hieron’s crown of pure gold.

Pelican Facts

  • The great white pelican catches about 1.2 kg of fish a day in its large throat pouch.
  • The brown pelican dives from a height of 15 m above the water to catch fish below the surface.
  • Great white pelican breeding colonies may number as many as 30,000 pairs of birds.
  • There are seven species of pelican. Most live and feed around fresh water, but the brown pelican is a seabird.
  • Pelicans are often found in large colonies, particularly during the breeding season.
  • A great white pelican comes in to land on the water.
  • One of the largest pelicans is the Australian pelican, which is up to 180 cm long and weighs about 15 kg.
  • The white pelican lays 1-2 eggs in a nest mound on the ground. Both parents help to incubate the eggs and care for the young.
  • Pelican chicks are able to stand at 3 weeks old and can fly at 7-10 weeks old.
  • In heraldry, a pelican is shown pecking its breast to feed its young on its blood. This may stem from the bird’s habit of resting its beak on its breast.
  • White pelicans work as a group to herd fish into a shoal by swimming around them in a horseshoe formation. Then they scoop up pouchfuls of fish with their large beaks.
  • In flight, a pelican flaps its wings 1.3 times a second. This is one of the slowest wingbeat speeds, when actively flying, of any bird.

Garden Facts

  • The ancient Chinese and Greeks grew fruit trees, vegetables and herbs in gardens for food and for medicines.
  • In the 1500s there were five famous botanical gardens in Europe designed to study and grow herbs for medicine.
  • The first botanical gardens were at Pisa (1543) and Padua (1545) in Italy.
  • Kew Gardens was once owned by the Royal Family, but since 1841 has been open to the public.
  • Carolus Clusius set up a famous flower garden in Leiden in Holland in the late 1500s. Here the first tulips from China were grown and the Dutch bulb industry began.
  • The most famous gardener of the 17th century was John Evelyn who set up a beautiful garden at Sayes Court in Deptford near London.
  • The Royal Botanic Gardens at Kew near London were made famous by Sir Joseph Banks in the late 1700s for their extensive collection of plants from around the world.
  • Today Kew Gardens has 33,400 classes of living plants and a herbarium of dried plants with 7 million species – that’s 98% of the world’s plants.
  • Plants such as rubber plants, pineapples, bananas, tea and coffee were spread around the world from Kew.
  • Lancelot ‘Capability’ Brown (1716-83) was a famous English landscape gardener. He got his nickname by telling clients that their gardens had excellent `capabilities’.
  • Ornamental gardens are ordinary flower gardens in which a variety of flowers are laid out in patterns that are pleasing to the eye.
  • Gardening has become one of the most popular of all pastimes.
  • All garden flowers are descended from plants that were once wild, but they have been bred over the centuries to produce flowers quite unlike their wild relatives.
  • Garden flowers like tea roses, created by crossbreeding two different species, are called hybrids.
  • Garden flowers tend to have bigger blooms and last for longer than their wild cousins.
  • By hybridization gardeners have created colours that are impossible naturally, such as black roses.
  • Ornamentals are flowers cultivated just for show.
  • Botanical gardens such as I hose at Kew, London, display collections of flowers from many parts of I he world.
  • I 8th-century botanist Carl Linnaeus made a clock by planting flowers that bloomed at different times of day.
  • The earliest flowerbeds were the borders of flower tufts Ancient Persians grew along pathways.
  • A herbaceous border is a traditional flowerbed that is planted with herbaceous perennial flowers such as delphiniums, chrysanthemums and primroses. It llowers year after year.
  • Herbaceous borders were invented by Kew gardener George Nicolson in the 1890s.

Sparrow Facts

  • More than 70% of all bird species – over 5,000 species altogether – are perching birds, or Passerines. They have feet with three toes pointing forwards and one backwards, to help them cling to a perch.
  • Perching birds build neat, small, cup-shaped nests.
  • Perching birds sing – this means that their call is not a single sound, but a sequence of musical notes.
  • Songbirds, such as thrushes, warblers and nightingales, are perching birds with especially attractive songs.
  • Usually only male songbirds sing – and mainly in the mating season, to warn off rivals and attract females.
  • Sparrows are small perching birds found in many parts of the world. Sparrows are seed-eaters with the house sparrow specializing in grain. Changes in farming practices are thought to account for this bird’s dramatic decline in numbers in Britain.
  • Starlings often gather on overhead cables ready to migrate.
  • Sparrows are small, plump birds, whose chirruping song is familiar almost everywhere.
  • Starlings are very common perching birds which often gather in huge flocks, either to feed or to roost.
  • All the millions of European starlings in North America are descended from 100 set free in New York’s Central Park in the 1890s.
  • Many perching birds, including mynahs, are talented mimics. The lyre bird of southeastern Australia can imitate car sirens and chainsaws, as well as other birds.
  • The red-billed quelea of Africa is the world’s most abundant bird. There are over 1.5 billion of them.

Flood Facts

  • A flood is when a river or the sea rises so much that it spills over the surrounding land.
  • River floods may occur after a period of prolonged heavy rain or after snow melts in spring.
  • Small floods are common; big floods are rare. So flood size is described in terms of frequency.
  • A two-year flood is a smallish flood that is likely to occur every two years. A 100-year flood is a big flood that is likely to occur once a century.
  • A flash flood occurs when a small stream changes to a raging torrent after heavy rain during a dry spell.
  • The 1993 flood on the Mississippi–Missouri caused damage of $15,000 million and made 75,000 homeless, despite massive flood control works in the 1930s.
  • The Hwang Ho river is called `China’s sorrow’ because its floods are so devastating.
  • Not all floods are bad. Before the Aswan Dam was built, Egyptian farmers relied on the yearly flooding of the River Nile to enrich the soil.
  • After the Netherlands was badly flooded by a North Sea surge in 1953, the Dutch embarked on the Delta project, one of the biggest flood control schemes in history.
  • Even when no one drowns, a flood can destroy homes and wash away soil from farmland, leaving it barren.

Galileo Galilei Facts

  • Galileo Galilei (1564-1642) was a great Italian mathematician and astronomer.
  • Galileo was born in Pisa on 15 February 1564, in the same year as William Shakespeare.
  • The pendulum clock was invented by Galileo after watching a swinging lamp in Pisa Cathedral in 1583.
  • Galileo’s experiments with balls rolling down slopes laid the basis for our understanding of how gravity affects acceleration (speeding up).
  • Learning of the telescope’s invention, Galileo made his own to look at the Moon, Venus and Jupiter.
  • Galileo described his observations of space in a book called The Starry Messenger, published in 1613.
  • Through his telescope Galileo saw that Jupiter has four moons (see Jupiter’s Galilean moons). He also saw that Venus has phases (as our Moon does).
  • Jupiter’s moon and Venus’s phases were the first visible evidence of Copernicus’ theory that the Earth moves round the Sun. Galileo also believed this.
  • Galileo was declared a heretic in 1616 by the Catholic Church, for his support of Copernican theory. Later, threatened with torture, Galileo was forced to deny that the Earth orbits the Sun. Legend has it he muttered `eppur si muove’ (`yet it does move’) afterwards

Cheetah Facts

  • Unlike most cats, cheetahs can hardly retract their claws at all. The claws grip the ground as they run, like the spikes on a sprinter’s shoes.
  • A cheetah can accelerate from 0 to 72 km/h in 2 seconds, and can reach a top speed of 120 km/h.
  • A silver vase (c.2300 Bc), found in the Caucasus, shows a cheetah in a collar, which suggests people used cheetahs then as hunting animals.
  • The 16th-century Mogul emperor Akbar kept 1000 cheetahs, which he used to hunt blackbuck.
  • Cheetahs have the same body length as leopards, but stand a good 35 cm taller on their long legs.
  • In the Kalahari Desert, cheetahs can survive for 10 days without water by eating wild melons.
  • Young male cheetahs often hunt in small groups (coalitions), and are heal t hier than solitary males.
  • A cheetah will chase a warthog that runs, but will usually leave one that stands its ground.
  • If a cheetah does not catch its prey in the first 300 to 400 m of the chase, it gives up and allows its heart beat to return to normal.
  • Cheetahs avoid lions, which will kill them.
  • Cheetahs often sit on rocks or termite mounds to get a better all-round view when resting.

Radio Telescope Facts

  • Radio telescopes are telescopes that pick up radio waves instead of light waves.
  • Radio telescopes, like reflecting telescopes, have a big dish to collect and focus data.
  • At the center of its dish, a radio telescope has an antenna which picks up radio signals.
  • Because radio waves are much longer than light waves, radio telescope dishes are very big – often as much as 100 m across.
  • Instead of one big dish, some radio telescopes use an array (collection) of small, linked dishes. The further apart the dishes are, the sharper the image.
  • The Very Long Baseline Array (VLBA) is made of ten dishes scattered all the way across the USA.
  • Radio astronomy led to the discovery of pulsars and background radiation from the Big Bang.
  • Radio galaxies are very distant and only faintly visible (if at all), but they can be detected because they give out radio waves.
  • Radio astronomy proved that the Milky Way is a disc-shaped galaxy with spiraling arms.

Ozone Layer Facts

  • Life on Earth depends on the layer of ozone gas in the air (see atmosphere), which shields the Earth from the Sun’s ultraviolet (UV) rays. Ozone molecules are made from three atoms of oxygen, not two like oxygen.
  • In 1982 scientists in Antarctica noticed a 50 percent loss of ozone over the Antarctic every spring. This finding was confirmed in 1985 by the Nimbus-7 satellite.
  • The ozone hole is a patch where the ozone layer becomes very thin.
  • The ozone hole appears over Antarctica every spring.
  • The ozone hole is monitored all the time by the TOMS (Total Ozone Mapping Spectrometer) satellite.
  • The loss of ozone is caused by manufactured gases, notably chlorofluorocarbons (CFCs), which drift up through the air and combine with the ozone.
  • CFCs are used in many things, from refrigerators and aerosol sprays to forming the foam for fast-food cartons.
  • CFCs were banned in 1996, but it may be at least 100 years before the ban takes effect. The hole is still growing.
  • UV rays from the Sun come in three kinds: UVA, UVB and UVC. Both oxygen and ozone soak up UVA and UVC rays, but only ozone absorbs UVB. For every
  • Meteorologists predict the world temperature will rise between 2 and 4°C by 2030 unless we 1 percent loss of ozone, 1 percent more UVB rays reach the Earth’s surface.

Lake Facts

  • Most of the world’s great lakes lie in regions that were once glaciated. The glaciers carved out deep hollows in the rock in which water collected. The Great Lakes of the USA and Canada are partly glacial in origin.
  • In Minnesota, USA 11,000 lakes were formed by glaciers.
  • The world’s deepest lakes are often formed by faults in the Earth’s crust, such as Lake Baikal in Siberia (see Asia) and Lake Tanganyika in East Africa.
  • Many of the world’s great lakes were formed by glaciations, and will eventually disappear.
  • Most lakes last only a few thousand years before they are filled in by silt or drained by changes in the landscape.
  • The world’s oldest great lake is Lake Baikal in Siberia, which is over 2 million years old.
  • The Great Lakes include three of the world’s five largest lakes: Superior, Huron and Michigan.
  • The world’s largest lake is the Caspian Sea (see Asia), which is a huge saltwater lake below sea level. It covers 371,000 sq km.
  • The world’s highest great lake is Lake Titicaca in South America, which is 3812 m above sea level.
  • The world’s lowest great lake is the Dead Sea between Israel and Jordan. It is 399 m below sea level and getting lower all the time.
  • The largest underground lake in the world is Drauchen-hauchloch, which is inside a cave in Namibia.