Plants as medicine

Plants have been used as medicine for atleast 100,000 years. In much of the world especially in China and India, herbal remedies are used more than any other kind of medicine. Today, scientists are still researching the valuable healing properties of plants for use in conventional medicines.

Can plants help fight cancer?

Several plants are effective against cancer tumours. One of the most famous is the rosy periwinkle. One of its extracts, vincristine, is very effective against some types of lukemia, a cancer of the blood.

Which plant aid digestion?

Many plants, including the herbs and spices used in cooking, help digestion. In Europe, the bitter extract of wild gentians provides a good remedy for digestive problems.

What is GINSENG?

Ginseng is a plant related to ivy, and has been used as a herbal medicine for centuries. It is claimed-but not proved-to help many conditions, including fatigue and depression, a kidney disease, heart problems, and headaches.

Which plant helps combat MALARIA?

Quinine , from the bark of the quinine tree, which grown from south America Andes, and can cure or prevent MALARIA. before the widespread use of quinine, Malaria used to kill two million people each year.

Which plant is believed to help ASTHMA?

Lungwort is a herb with purple flowers and spotted leaves that are said to look like lungs. For the reason, it is sometimes used to treat asthma. That is no definate proof that it works.

Can WILLOW help pain?

Willow twigs were once chewed to give pain relief. A compound similar to drug aspirin was once extracted from willows and the herb meadowsweet, known as spiraea-giving aspirin its name.

Plant Products

Plant products are used for different uses, depending on their natural properties. The softness of cotton makes it ideal for clothing. The Springiness of rubber makes it perfect for products from rubber bands to rubber gloves

How is cork produced?

Cork comes from a tree called the cork oak. The cork is the thick, spongy bark. It is stripped away from the lower trunk, then left to grow upto ten years before the next harvest. Cork is used to make many things, from bottle corks and bulletin board to floor tiles.

What is kapok?

Kapok is similar to cotton, It comes from the kapok tree, which is cultivated in Asia and can be as tall as 160 feet. The fluffy seed fibres are used to stuff mattresses, jackets, quilts, and sleeping bags.

How is cotton turned into cloth?

Cotton is a soft fibre that grows naturally around the seeds of the cotton plant, forming "bolls". These are "ginned" to remove the seeds; spun, or twisted, into thread; and then woven to make a cloth.

What is rubber?

Rubber is sap of some plants, particularly the para rubber tree. The trees are pierced, or trapped, and the sap drips slowly into the waiting container.

What wood makes the best cricket bat?

The best cricket bats are made in India, from the willow, a white willow. The blade (the part of ball strikes) is made from, and the handle from different wood or cane.

Can plants produce fuel to run cars?

The copaiba tree of Amazon rain forest yield an oil similar to diesel fuel that can be used to run engines. Oilseed rape, soybean, and the petroleum nut tree of southeast Asia can also used to produce biofuels, or plant fuels. As crude oil reserves are used up, biofuels may become important.

Materials

Why are saucepans made of metal?

Saucepans are made of metal because most metals heat up quickly. Metal atoms vibrate easily when heated, rapidly passing on the vibrations of atom around them. This makes metals good conducted (carriers) of heat. Most metals, such as iron, are strong, shiny, hard solids, but metals all have different properties. Aluminium, for example, is light and easily molded.

How is glass made?

Glass is made by heating together sand, ash, and stone in a hot furnace. The molten (liquid) glass is then rolled into sheets, put in a mould, or blown into shapes. It hardens to a transparent solid when it cools. Glass is waterproof and reflects light or let light through it. It is used to make windows and jars, and also lenses and mirrors.

What are plastics?

Plastics are artificial materials made by heating chemicals found in petroleum (oil). Plastics have many useful properties. They can be be molded into different shapes, they do not break easily when dropped, and they are light and waterproof. There are many different types of plastic. For example, Plexiglass is a tough, tranperant plastic and polystyrene is a kind of foam used for insulation (to trap heat).

When is plastic a problem?

Plastic is a problem because it does not biodegrade, or break down, as food, paper, or wood do. This means plastic piles up in large holes in the ground or floats around oceans, washing up on beaches. Scientists are developing plastics that break down but can still protect and store goods.

Mountain and valley

How do mountains form?

Some mountains form from volcanoes. Dome mountains occur where magma near the earth's surface forms a rounded bulge of rock but does not erupt to become a volcano. Fold mountains form when two colliding plates cause the earth's crust to buckle and fold, making mountain ranges. Block mountains form when fractures in the earth's crust push a block upward.

Do mountains continue to grow?

Yes, some mountains continue to get taller after they first form! For example the Himalayas are growing up 2 inches every year. The Himalayas were formed 50 millions year ago when two of the mountain plates collided. As the plates continue to push each other the mountains are gradually getting higher-and they are getting even higher to climb!

What is a glacier?

A glacier is a huge river of ice. A buildup of snow and ice in a very cold, high mountain areas causes the river of ice downhill. Most glaciers flow so slowly you can not tell they are moving. As glaciers move, they carry rocks along with them that help gouge out valleys, or deep grooves, into the land through which they pass.

Where is the tallest mountain?

The tallest mountain is Mauna Kea on Hawaii. It measures 33,375 feet from base to peak, but most of it is underwater. Only 13,795 feet of it are above sea level. On land, Mountain Everest is the highest mountain, reaching 29,035 feet above sea level. Also on Hawaii is Mauna Loa, the world's biggest 🌋 Volcano.

Light and Dark

Where does light came from?

The Earth's biggest source of light is Sun. Heat and light energy by sun created by the sun travels through space in straight lines called rays at almost 187,000 miles per second. The Earth's spins around once a day, changing which part of globe gets sunlight. This creates day and night. Other things that radiate, or give off, light include electric lightbulbs, candles, and television sets.

What are shadows?

Shadows happen in places where an object

Stops light from getting through. Materials that light shines through fully are called transparent. Translucent materials only let a little light through. Opaque material don't let any light through at all. The shape of the shadow depends on the object blocking the light. If an object is moved closer to a light source, it's shadow gets bigger because it blocks more light rays.

Why do mirror reflect images?

All surfaces reflect light but if they are bumpy, the light rays are reflected in all directions. Mirrors are made from very smooth surfaces that reflect the rays back in the same pattern as they hit it, creating a clear image of any object. Words reflected in a mirror appear back to front, as if they were facing away from us and we were looking through the page.

How do periscopes work?

Periscopes are devices that use reflecting mirrors in order to see things from a lower level. An Angled mirror reflects an image, made up of light, down a tube. A second mirror at the bottom of the tube reflects the light again to turn the image back the right way up. Periscopes are often used to see surface ships from underwater submarines, or to see over people's heads in crowds.

World under water - Future disasters

If our planet continues to warm up, we could all be in deep trouble. Water expands as it heats, so the ocean would rise and threatens coastlines. There is a danger, too, that the polar ice caps may gradually melt as temperatures increase. Some scientists predict that the combined effect could cause a catastrophic rise in sea levels by the end of 21st century. Without food defences in place, that would put major cities at risk in many heavily populated regions in the world.

Wet outlook

The prospect of coastline cities such as new york sheltering behind sea walls in centuries to come is real. In the last 100+ years sea level has risen by 10-25 cm, and the united nations forecasts that it will rise four times faster in 21st century. Ocean currents will cause much greater rise in some regions, threatening coastlines in future centuries with tides three to five metres higher than present levels - even without the extra hazard of melting polar ice caps.

Disappearing from the map

Some scientists have estimated that sea levels could rise three metres by year 2100. If this happens, dozens of coastal belts, including major cities such as Bangkok, St Petersburg and New Orleans, would face disastrous flooding. Whole regions including southern Florida in the USA, much of the Netherlands and half of Bangladesh would be awash. The area at risk account one third of the world's vital crop growing land.

Mind the gap

Pollution causes more danger than global warming. Chemical called CFCs - used, for example, in aerosols - drifted up in the sky for decades, destroying the ozone layer, the part of Earth's atmosphere that protects us from cancer causing ultraviolet sunlight. The risk was ignored, until a huge whole was detected in the ozone layer over Antarctica in 1987. CFCs are now controlled, but too late to prevent this grave enviromental disaster.

                         Figure is not Thames barrier

Against the tides

The Thames Barrier, which was completed in 1984, protects London from the dangerous high tides that began to flood the city in the 20th century. The main gates, which each weigh 3,700 tonnes, close into a wall as high as a five storey building. The barrier has to be raised 33 times in its first 15 years.

Getting Hotter - Future Disasters

Think of a world as a greenhouse. The glass walls and proofs are the Earth's atmosphere, getting in the sunlight and trapping heat to keep the inside warm. But there's is a growing problem. Gases from field burnt off industry, transport and deforestation are building up in the atmosphere, so that heat is escaping more slowly. The greenhouse effects is causing global warming, which is already a cause for alarm.

Long range forecast

If global warming continues, the polar ice capabilities could melt, and climate zones across the world will move northwards. In the latitudes of Europe, for example, cool countries such as France, Germany and Britain would become sub-tropical. Sunny Spain and Italy would be scorched into deserts, and hot, dry North Africa would turn into a vast expanse of grassy savannah.

Paris in the heat

In the future, could northern cities such as Paris be sweltering in sub tropical weather?
Yes, say some experts, if global warming causes a shifted in world climate belts. While northern regions might welcome warmer weather, the possible effect on agriculture could be calamitous. The world cereal-growing regions could turn into deserts, leading to mass famine. Global warming could make change to rainfall patterns too. Regions with regular rainfall year round may soon face monsoon like downpours that cause disastrous floods. If nothing else, the world will begin to look very different. The pyramids of Egypt, for example, would no longer stand in dry desert sands, but in green grasslands.

Unwelcome visitor

Temperature may rise by as much as three degrees centigrade during the next 100 years - five times the rise during the last. This would enable warm climate plant and wildlife species to migrate North, perhaps bringing unwelcome visitors such as the deadly tsetse fly and malarial mosquitoes to the part of Europe and the United States, where these insects have never been a threat before.

Building up a storm

Global warming is blamed for an increase in number of violent storms. Hurricanes such as Mitch, which devastated Central America in 1998, are said to have become 40 percent more frequent since 1970.

Medical threats - Future Disasters

Our most dangerous are invisible. In spite of medicines amazing progress in 20th century, microscopic monsters continue to stock us. Deadly new viral disease such as AIDS and ebola have no cure so far. And infectious bacteria, responsible for killers such as diphtheria and tuberculosis, are staging come back too. They have begin to develop resistance to antibiotics, the miracle drugs that doctors once hoped would consign them to history.

Risky business

To find new treatments for infectious diseases, researchers test thousands of different chemicals, one by one, on samples of bacteria that cause them. It is a time consuming task, and often a hazardous one. Testing deadly germs calls for extreme care and special precautions.

Survival expert

MRSA - Methicillin-resistant staphylococcus aureus - is a 'super bug' which even powerful antibiotics cant destroy. The bacterium lives in hospitals, where of attacks - and skills - patients who have had operations. MRSA is so dangerous that some hospitals refuse to admit patients who have that infection. Scientists are developing drugs to combat MRSA, but these miniscule organisms learn to change their form and behaviour just as quickly as new drugs appear. Their struggle to survive is as determined as that of any other life form.

Ancient remedy

In the search for cures, medicines turn to some surprising sources. A powerful new treatment for malaria, which kills millions each year, is based on a two thousand year old Chinese herbal remedy, and taken from the common plant family Artemisia.

Persistent killers

New disease pose a constant threat to disastrous epidemics. In Africa, millions live in the fear of the ebola virus, named after a deadly outbreak in the ebola river region of Zaire in 1976. One sufferer was transferred to the capital, Kinshasa, where the disease is found to be new - and infectious enough to threaten the city's two million people. The hospital, and ebola region, were instantly sealed off. The fever kills up to 90 percent of its victims and can not be cured. It broke out again in 1995, killing most of the staff and patients at a hospital in kikwit, Zaire. So infectious is the virus that even burial parties must wear protective clothing.

Crowded Planet - Future Disasters

Thanks to 20th-century technology, we live longer, travel farther and produce more goods. We also multiply. There are now more than 7 billion of us, more than four times the number 100 years ago. We run a billion motor vehicles on our roads and consume more and more of earth resources. In other century, there could be 15 billion people, all in need of jobs, homes, food, healthcare and transport. Unless growth slows, the world could be overwhelmed.

Population explosion

The united nation hopes people will learn to limit there children to two per couple.
Population growth next century will depend on when this target is reached. The graph shows three possibilities. The highest figure is the likeliest, and could well be exceeded.

Chaos in the streets

The city of the future is crowded, nightmare vision. Dirty, traffic choked the streets and pavements are squeezed between high rising buildings, in which solitary workers sit all day at computers in sound proof sealed offices. Some cities are, of course, just like this now, but it is going to get much worse. Britain, for example, already has the world's most crowded road networks, with 100 vehicles for every kilometre. With car use growing at its present rate, there will be 50 percent more traffic by 2030. This dependence on cars will cause yet more problems of congestion, accidents and pollution.

Throwaway society

European households each throw out a ton of rubbish every year. In the U.S.A, it is even more. Disposal by burying or burning delayed the environment - and the problem gets worse as people worldwide generate more and more waste.

Uncontrolled spread

Population in the industrialized nations of Europe and North America are growing slowly, but in the developing world, high birth rates double some countries numbers every 20-30 years. Millions flock to cities, hoping to share the benefits of consumer society. The many who find no work face a grim life in shanty towns such as those of Rio de Janeiro in Brazil - already overcrowded and beset by poverty and disease.