Wonderful Salt

Life without salt would be more than bland.

Salt either comes from evaporating seawater or is mined.

Most salt fields (spots of very salty water) are near the ocean. Nearby salt fields include those in Kampot, Cambodia an Nha Trang, Vietnam.

There are salt mines all over the world where people mine for rock salt. These mines are dried-up lakes and oceans. As the salty waters become enclosed or buried, the salt in the water turns into solid layers.

In the past, salt was so precious that salt roads were made, mostly to enable the transportation of salt to cities where there were no salt lakes or nearby seashores.

In certain cultures, salt was sacrificed to the gods. It was considered to have magical powers, too. Doctors would sprinkle wounds with salt in the hope of fighting off infection.

Today, say is sold in every shop and supermarket, and is more than a seasoning. Salt is used to make leather, roads, soap, glass, chlorine and paper.

It is also used to preserve hay and food, purify and soften water, refine metals, melt snow and ice, and freeze ice cream.

Salt is useful stuff, indeed!

Merdeka & The Formation of Malaysia

Source: Wikipedia

The effort for independence was spearheaded by Tunku Abdul Rahman Putra Al-Haj, the first Prime Minister of Malaysia, who led a delegation of ministers and political leaders of Malaya in negotiations with the British in London for Merdeka, or independence along with the first president of the Malayan Chinese Association (MCA) Tun Dato Sir Tan Cheng Lock and fifth President of Malaysian Indian Congress Tun V.T. Sambanthan.

Once it became increasingly clear that the Communist threat posed during the Malayan Emergency was petering out, agreement was reached on February 8, 1956, for Malaya to gain independence from the British Empire. However, for a number of logistical and administrative reasons, it was decided that the official proclamation of independence would only be made the next year, on August 31, 1957, at Stadium Merdeka (Independence Stadium), in Kuala Lumpur.

Tunku Abdul Rahman Putra Al-Haj announced the independence of Malaya from
the British on August 31, 1957 at Stadium Merdeka.

The Federation of Malaysia, comprising the States of Malaya, North Borneo (later renamed Sabah), Sarawak and Singapore was to be officially declared on the date August 31, 1963, on the 6th anniversary of Malayan independence.

However, it was postponed to September 16, 1963, mainly due to Indonesian and the Philippines' opposition to the formation of Malaysia. Nevertheless, North Borneo and Singapore declared sovereignty on August 31, 1963.

Indonesian opposition later escalated to a military conflict. Indonesia considered Malaysia as a new form of colonization on the provinces of Sarawak and Sabah in the island of Borneo (bordering Kalimantan, Indonesia), which they laid claim on.

To assure Indonesia that Malaysia was not a form of neo-colonialism, a referendum, organized by the United Nations, and the Cobbold Commission, led by Lord Cobbold, were formed to determine whether the people of Sabah and Sarawak wished to join Malaysia. Their eventual findings which indicated substantial support for Malaysia among the peoples of Sabah and Sarawak, cleared the way for the final proclamation of Malaysia.

The formation of the Federation of Malaysia was then announced on September 16, 1963 as Malaysia Day. The Independence Day celebration is still held on August 31, the original independence date of Malaya. However, this has caused some minor discontent among East Malaysians in particular since it has been argued that celebrating the national day on August 31 is too Malaya-centric.

The flag of Malaysia, also known as the Jalur Gemilang ("Stripes of Glory").

Radioactive - The Brighter Side

Radioactive substances can be useful. In fact, some of them are used in fields like medicine, agriculture and archaelogy.

Tracers

• In the medical field, the radioactive iodine-131, whose pathway can be traced, is injected into patients with thyroid gland dysfunction to check the function of the glands and detect the growth of tumours.

• To trace water leakages underground, radioactive substances are introduced into water pipelines. When there is a water leakage, radioactive detectors such as Geiger-Muller counter will provide radioactive readings.

Sterilisers

• Gamma rays are used to sterilise medical instruments to prevent contamination. In the food industry, they are used to prevent decay of food so that the food can last longer and be exported. In agricultural field, gamma rays are used to sterilise pests.

Nuclear reactors

• In a nuclear reactor, radioactive substances decay and give out a great amount of energy, which is used as an electrical energy source. However, this type of energy is expensive.

Nuclear energy

• Nuclear energy is derived from the nucleus of a substance. Nuclear energy can be produced by fusion (joining two nuclei of atoms to form a heavier nucleus) or fission (splitting the nucleus into two smaller and lighter nuclei, and releasing one or more neutrons).

Bad Air

Fumes from cars and factories can make you cough or even feel sick. But did you know that indoor air can be just as bad for our health?

Sick Building Syndrome (SBS) is a form of indoor air pollution that happens when a building isn't built or maintained properly.

People in these places suffer from health problems but often don't realise it's the building that's causing them.

Until 1970s, toxic materials like asbestos and lead used in insulation, pipes, tiles and other items was a big cause of SBS. Asbestos and lead poisoning cause headaches, fever, nausea and even lung cancer and brain damage.

Today, lead and asbestos are no longer used in buildings. But common products like glue, carpeting, treated wood and cleaning fluids also release toxic fumes. When these are used during renovations, people have to stay outside - or wear a safety mask.

Moulds, fungi and bacteria also cause SBS. The bacterium Legionella is especially dangerous as it causes Legionnaire's Disease and Pontiac Fever that can kill.

Modern buildings are specially designed so there are no damp hidden corners where these organisms can breed. But the best prevention is to clean filters, fix leaking pipes and do regular maintenance.

Well-designed buildings also have fresh air flowing through that flushes out fumes and lets in the oxygen we need to maintain good health.

The important thing is not to confuse cold air from air-conditioners with the good stuff. We have to open windows regularly to let fresh air in.

Making Life

It used to be that the idea of copying people was the stuff of science fiction. But now, cloning is a science.

About 80 years ago, Aldous Huxley wrote a bestseller called Brave New World. In his futuristic novel, everyone on earth is cloned and conditioned to be the same.

At the time Huxley was writing the novel, doctors were only finding out about blood types, vitamins, and drugs like penicillin. Cloning was as impossible as space flight then!

Cloning is a natural phenomenon. Plants like Quaking Asp, Japanese Yellow Rose, and Wisteria reproduce by making exact copies of themselves.

Bacteria, algae, and single-celled organisms such as paramecia and amoebas also reproduce by cloning. Some starfish also have this ability.

Cloning happens naturally when mammals like us give birth to identical twins. However, in this age, artificial cloning is becoming a science.

Farmers clone fruits and vegetables like grapes and potatoes to guarantee top taste and quality. After the scientists in Scotland successfully created Dolly the sheep in 1996, many hope livestock will be cloned soon too.

Others are excited at the thought of cloning endangered species. Although there are clear advantages of cloning, not everyone is happy about this new technology.

Critics warn that playing god has many dangers since we still do not quite understand how nature works.

If cloning becomes as easy as that depicted in Brave New World, would you be in favour of copying sheep, salmon, and may be people?

Dolly the Sheep remains are exhibited at the
Royal Museum of Scotland.

Air Pollution

We breathe in and out between 15 to 25 times a minute, inhaling between 11 and 13 cubic metres of air each day.

Every time we breathe in, our lungs take oxygen from the air and pump it into our body. The oxygen helps cells convert food into energy.

When we breathe out, the body washes out carbon dioxide. If the air is clean, everything work beautifully. Unfortunately, the way we live causes air pollution.

Burning fossil fuels for energy, manufacturing, getting rid of rubbish and using chemical fertilisers on farms all release toxins such as unburned hydrocarbons, carbon monoxide, sulphur dioxide, nitrogen oxides, ozone and lead.

Air pollution chokes up the lungs, causing breathing difficulties. Long-term exposure causes respiratory illnesses like asthma and bronchitis, heart disease and cancer.

The World Health Organization (WHO) warns that air pollution kills 2.4 million people annually. Bad air kills more people than car accidents!

The main causes of air pollution include burning fossil fuels for power and transport. Another big problem caused by farmers in Malaysia and Indonesia who burn forests to clear land for crops.

This means that every year in August and September, pollution from this "slash and burn" system causes people from Myanmar to Singapore to stay indoors.

Air pollution isn't a local problem - it's everyone's problem. Air pollution isn't just smelly, it can kill us.

Info:

1. The Pollution Standard Index (PSI) calculates how many pollutants are in the air.
   
   
2. A PSI reading of over 400 means hazardous!
   
   
3. Trapped air pollution from coal fires killed 4,000 people in six days during the Great Smog of London in 1952. Around 8,000 more died during the following months.
   
   
4. An industrial gas leak in 1984 in Bhopal, India, killed more than 2,000 people instantly, 6,000 in the following weeks, and injured between 150,000 and 600,000 more.

Discovering Radioactive Elements

Marie Curie discovered the nature of radioactive elements - but it killed her.

In 1896, French scientist Henri Becquerel discovered that uranium salts gave off energy. But he couldn't figure out exactly what was going on.

Marie Curie, a Polish scientist living in France, called these rays "radioactivity". Marie's husband Pierre Curie was a noted chemist. Working together, the Curies discovered two other radioactive elements in 1898: polonium and radium.

By 1903, they worked out what was happening. Certain types of atoms are unstable. They decay over many years and eventually become different and stable elements.

For example, uranium-238 decays into thorium-234 over 4.5 billion years. It then takes about another 341,000 years to turn into a stable element called lead-206.

While the nucleus is changing, invisible radioactive radiation is released. As these rays carry a lot of energy, they can be very useful - or very dangerous.

Positive uses include using radioactive radiation to kill cancer cells. This is called "radiotherapy". It's also used to sterilise medical equipment, detect blood clots, and to treat food.

But radioactive radiation can also kill and mutate body cells, causing internal bleeding, infertility, cancer and many other health problems.

Back in the early 1900s, nobody realised how dangerous radioactive elements are. Marie Curie died as a result of leukaemia caused by the action of radiation.

Facts:

1. Marie Curie was born Marie Skodowska on November 07, 1867 in Warsaw, Poland.
   
   
2. Marie Curie won the Nobel Prize twice. In 1903, she shared the Nobel Prize for Physics with Henri Becquerel and Pierre Curie. She was also the sole winner of the 1911 Nobel Prize for Chemistry.
   
   
3. Pierre Curie was killed in a street accident in 1906.
   
   
4. Irradiation involves the use of radioactive radiation to kill bacteria in food.
   
   
5. A Geiger Muller counter detects radioactive radiation. A sphygmomanometer measures blood pressure.

Water Waves

Burning coal, oil and gas for fuel causes lots of pollution. Now scientists think the sea might give us clean power.

When breezes touch the surface of the ocean, waves appear. Mild winds produce low waves. But big winds can create waves that are 18m high - that's as tall as a six storey building.

We power cars, factories, air conditioning and other systems by burning fossil fuels. But burning oil, gas and coal causes pollution. Fossil fuels are also very expensive.

In the 1970s, scientists began to look for renewable, non-polluting energy sources. Today, there are several methods to harvest energy from the sea.

The Oscillating Water Column System (OWS) gathers the energy of waves breaking onto the shore. Engineers arrange a series of hollow pipes just under the water line. When the waves run in and out of the pipes, they create a stream of moving air. This movement turns a turbine and generates electricity.

The buoyant moored system is a type of rafr that floats on the ocean's surface. When waves move it up and down, the energy of this movement turns turbines to create electricity.

Wave farms do have some drawbacks. First, these projects take up a lot of space. Also, they need to be built with the strongest materials to survive corrosion and storms. This can be expensive.

But as fuel prices increase, more wave farms are built. Scotland and Portugal now have commercial wave farms. May be, we may have one in Malaysia soon too.

** How Wave Energy Works at science.howstuffworks.com/wave-energy.htm has great diagrams that show oscillating water column systems and buoyant moored systems. The also explain pros and cons of wave farms in detail.


Information:

• The top of a wave is called the crest or peak.
  
• The lowest part or hollow of a wave is called the trough.
  
• No two ocean waves are exactly alike.
  
• Tsunamis are not caused by wind but by geological changes like earthquakes.

Joke & Riddle

1. What lies at the bottom of the sea and shakes?
   A nervous wreck.
   
   
2. What has no beginning, end or middle, and touches every continent?
   The ocean.

Battery Biohazard

Throwing your batteries in the dustbin can harm the environment.

You've probably got a dozen things that are powered by batteries. Just check your mobile phone, calculator, television remote control, camera and torchlight.

Batteries are incredibly useful but they run on poisonous chemicals and metals like mercury, lead, cadmium and nickel. That is why you mustn't throw old and damaged batteries in the dustbin.

When batteries are thrown into a rubbish heap or a landfill, the chemicals they run on leak into the soil and groundwater. Nobody wants that in their food or water!

If you throw a battery into incinerator, heavy metals like mercury can vapourise and be released into the air. When it rains, they fall back to the earth, poisoning soil, rivers and oceans.

Burning batteries leave ashes with concentrated cadmium and lead. When these are dumped, the poison leaks into the environment.

You can reduce the amount of batteries you use by buying rechargeable products. They cost a little more, but you can use them many times.

You can also buy batteries with fewer dangerous chemicals. Modern alkaline batteries have up to 90% less mercury than those used 20 years ago. Some are completely mercury free. Just read the label!

When your batteries dies, take it to a recycle centre. The recycle centre disposes of any leftover chemicals in such a way that they can't harm the environment.

*******
Info:

1. Batteries are electrochemical devices that convert chemical energy to electrical energy.
2. The modern battery was invented by Italian physicist Alessandro Volta in 1800.
3. A typical lead-acid car battery today is now made up of about 70% recycled lead and plastic.
4. Malaysians produce enough rubbish every day to fill up the Petronas Twin Towers in less than 10 days.

*******

Reaction & Changes

Physical changes



When a substance undergoes physical changes, its physical composition changes but its chemical composition remain the same.



Eg: Ice, water and water vapour may exist in different physical states - solid, liquid and gas respectively - but they are still made up of the same chemical composition, H₂O.



Also, physical changes are reversible.



Eg: Water turns into ice when cooled. To get back the water, heat the ice.



Forces like temperature and pressure can effect physical changes.





Chemical changes



The chemical composition of a substance is changed when it undergoes chemical changes. As a result, a new substance is formed. The process is irreversible.



So, how can a chemical change in a substance be identified?

• Change in colour.
• Release or absorption of energy or heat.
• Release of odour.
• Production of gases or solids.

Note: In a chemical reaction, matter is neither destroyed nor created. The particles of an original substance are rearranged to form a new substance. The number of particles that exists before and after the reaction is the same.



Exothermic vs Endothemic



In chemical reactions, heat is either released (exothermic reaction) or absorbed (endothermic reaction). Any change of physical state from solid to liquid is an endothermic reaction as heat is absorbed to push the particles further apart to change its physical state.



However, any change of physical state from liquid to solid is an exothermic reaction as heat is released to push the particles closer together.



To determine whether a reaction is endothermic or exothermic, use a thermometer.

Gilt & Gold Leaf Treasures

Covering objects with a thin layer of gold is an ancient technique.

If you can't afford a solid gold ring, you can opt for a gilded or gold-plated one, thanks to Italian chemist, Luigi Brugnatelli's invention of modern electroplating in 1805.

Even before his discovery, the act of coating ordinary metal objects with gold and silver had been in practice.

Some kings would have gilded crowns; aristocrats would order for picture frames, statues, tombs and ceilings to be coated with gold leaves.

Gilded statues and ceilings could be found in temples and public building as well.

Over those years, several gilding techniques were used. For example, when gilding an iron crown, smiths would hammer a thin layer of gold, lay it over the crown and then bake the two into one piece.

Other objects that could not be heated like wooden picture frames and ceilings were treated differently.

Artists would hammer gold into very fine sheets called gold leaves, and then cut and glued them in place on the objects.

Archaeologists have found gilded and gold leaf artworks dating back to 1,500BC in Greece, Egypt and China.

As these works from the Minoan, Egyptian and Shang dynasties are very sophisticated, many believe that the techniques used in their production are much older - exactly how old, though, remains a mystery.

Facts;

1. By weighing his king's crown in water, ancient Greek mathematician Archimedes could work out whether it was solid gold or gilded.
   
   
2. One of seven wonders of the ancient world was a 12m high gilded statue of the Greek god Zeus at a temple in Olympia.
   
   
3. Alessandro Volta was a professor of physics at the University of Pavia in Italy.
   
   
4. Gold plating is used in electronics to create corrosion-resistant connectors and circuit boards.

Gilded frame ready for burnishing
with agate stone tool

A Chinese Tang Dynasty gilt hexagonal
silver plate with a Fei Lian beast
pattern, 8th century CE.

Father of Mathematics

Archimedes was the world's greatest mathematician but for centuries few people realised his talents. Archemedes was born around 287BC in Syracuse on the island of Sicily.

Althogh Sicily is now a part of Italy, it was at that time a part of Greece. The Greeks and their neighbours, the Romans of Italy, were fighting for dominance.

As Archimedes was a friend of King Hieron II, the ruler of Syracuse, he took part in the wars against the Romans.

The young Archimedes showed exceptional skills as a mathematician and engineer. Not only did he prove that the surface area of any sphere is four times that of its greatest circle, he also worked out the steps to calculate the volume of a sphere.

When King Hieron was presented with a crown, Archimedes was able to determine the gold content in it by weighing it in water. His other contributions included the Archimedes' claw, a weapon that could sink ships, and the Archimedes' screw, a machine that could pump up water without using electricity.

Archimedes was such a genius that when the Romans invaded Syracuse, their general gave orders that the mathematician should not be harmed.

However, Archimedes killed by a Roman soldier in one of the battles. He was buried in a tomb decorated with his favourite mathematical proofs.

Althogh Archimedes' formulae were popular, much of his work was forgotten until his books were translated. Arabic versions in the 8th century inspired scientists in the Middle East whereas Latin translations in the 16th century inspired European scientists.

Johannes Kepler, Galileo Galilei, Rene Descartes and Pierre de Fermat were among the influential scientists inspired by Archimedes.

Hence, it is no wonder that Archimedes is now called the father of mathematics.

A sphere has 2/3 the volume and surface area of its circumscribing cylinder.
A sphere and cylinder were placed on the tomb of Archimedes at his request.

Archimedes may have used his principle of buoyancy to determine whether
the golden crown was less dense than solid gold.


The Archimedes screw can raise water efficiently.

Archimedes may have used mirrors acting collectively as a
parabolic reflector to burn ships attacking Syracuse.

Archimedes used the method of exhaustion
to approximate the value of π.

As proven by Archimedes, the area of the parabolic segment in the upper figure
is equal to 4/3 that of the inscribed triangle in the lower figure.

Archimedes is said to have remarked about the lever:
Give me a place to stand on, and I will move the Earth.

Disappearing Life - As Forests Disappear, Biodiversity Does Too

When people first started farming some 10,000 years ago, about two thirds of the world's land were covered within forests.

By 2005, less than one third of the earth's land is forested. As the forests dissapper, so do many of the animals and plants that lived there.

Studies predict deforestation will cause 42% of South-East Asia's land species to dissappear by 2100.

Our oceans are also in trouble. Over-fishing is killing the ecosystems. Since 1950, about 30% of shark, tuna, and cod have recorded a decline in their population. Other seafood species have also declined by more than 90%.

Scientists warn that unless fishing methods change, there will be no seafood left by 2048. Sustainable farming, fishing, and forestry methods can help. Human population control is also vital.

World population hit 6.5 billion on Jan 25, 2006 and is predicted to reach 9 billion in 2050. Scientists say that if world population growth doesn't slow down, 80% of the world's forest will be gone by 2030.

Facts:

• South America is the continent with the most forests. About half of its land is covered with forest.
• Deforestation was once declared a national emergency in the Phillipines, Thailand and India.
• About 25% of mammals, 12% of birds, 33% of all amphibians and 70% of the world's known plants are listed as threatened.

Soap - Cleaning Concoction

Soap. We use it in our daily life since birth but just much do us actually know about it.



What is soap?

Soap is a mixture of salts of fatty acids.

Eg: Natural soaps are sodium or potassium salts or fatty acids, which are originally sourced by boiling lard or other animal fat together with lye or potash (potassium hydroxide). (Note that fat is an acid, lye or potash is a base, and soap is a salt).



Like all salts, soap contain a positive ion, usually Na⁺ or K⁺, and a negative ion.



How is soap produced?

Soap is produced through a chemical reaction between an acid and a base. This process is known as saponification. A myriad of products, ranging from bar soap and toothpaste to shaving cream is made through method. The only difference is the type of fat and the type of base that the product is made from.



The following are the descriptions of five different types of soap.

1. Deodorant soaps
   
   Soaps that have been added with antibacterial agents to reduce odour-causing bacteria.
   
   
   
   
2. Cream soaps
   
   Soaps that contain cold cream materials, moisturisers and emollients; particularly good for dry and delicate skin.
   
   
   
   
3. Medicated soaps
   
   Soaps that contain antibacterial ingredients to treat acne and other skin disorders; require thorough rinsing and are not recommended for sensitive skin.
   
   
   
   
4. Oatmeal soaps
   
   A rough-textured soap that has been added with oatmeals as a mild abrasive and lather; good for oily, dry, and normal skin.
   
   
   
   
5. Floating soaps
   
   Soaps that have air bubles in them to lower their density, thus causing them to float.

Fermenting and Distilling

Most alcoholic drinks contain ethanol, which also called ethyl alcohol. One of the common processes in the production of alcohols is fermentation.

Fermentation is the use of yeast to convert glucose (or sugar solution) into alcohol (specifically ethanol) and carbon dioxide.

Glucose + Yeast -> Ethanol + Carbon dioxide

** Sugar canes are among the crops used for ethanol production.

The zymase enzyme in yeast is the catalyst for the reaction as it carries out anaerobic respiration on glucose, thus changing it into ethanol and carbon dioxide. Fermentation stops when the ethanol gets too concentrated and denatures the enzymes.

The resultant carbon dioxide gas escapes into the air, leaving a mixture of ethanol and water. Ethanol can then be separated from the mixture by fractional distillation.

Fractional distillation is based on the concept that two liquids have different boiling points.

The mixture of ethanol and water is heated until it boils. The liquid with the lowest boiling point boils first and vapourises.

The gas vapours are cooled in the condenser until the temperature falls below the boiling point. When they are condensed back into liquid, they are collected in a container.

The collected liquid is called the distillate, which means it has been distilled.

Freons & CFCs - From Wonder Chemical To Super Danger

CFCs seemed safe at first. But 40 years after they had been developed, scientists discovered the terrible truth.

CHLOROFLUOROCARBONS (CFCs) are covalent compounds whose chlorine, fluorine and carbon atoms are bounded by covalent bonds.

During the 1930s, E.I. duPont de Nemours & Company trademarked varies CFCs under the name Freon.

Initially, everyone thought Freons were fantastic. Freons are colourless, odourless, non-flammable and non-corrosive. It is a non-toxic to breathe in small amounts of Freon too.

As they have a low boiling point, Freons are ideal for systems that require cooling. Thus, Freons became widely used in fridges, air conditioning units and other chilling appliances.

When manufactures learnt that Freons were excellent aerosol-spray propellents, a myriad of products, from hair spray to oven cleaners, ensued. Freons were also used in fire estinguishers since they were great foamblowing agents, as well.

It was in the 1970s that scientists discovered Freons were not as safe as everyone had thought. They found that once let into open air, Freons reacted with the ozone in the atmosphere.

The earth's ozone layer is band of air with a high ozone content, which lies 32km to 48km above the planet's surface. It is very important part of the atmosphere because it protects us from solar ultraviolet radiation, which can cause skin cancer.

At the time, companies refused to believe that Freons were destroying the ozone layer. However, when more and more studied proved freons were dangerous, laws were made to ban their use.

By 1996, most countries had banned the use of Freons and other CFCs.

Facts:

• Thomas Midgley Jr and Charles Kettering were the American scientists who invented Freons.
• We can tell which chemical compounds Freons are made of by their number. For example, Freon-11 is trichlorofluoromethane.
• In 1986, the global consumption of CFCs was about 1.1 million tonnes. In 1997, it dropped to about 146,000 tonnes.

N-H Coordination

Body coordination is important to help us avoid injuries as well as adapt to changes around us. As the parts of our body communicate in unison with each other, a series of movements occurs in response to a stimulus.

There are two types of body coordination; nervous coordination and hormonal coordination.

The nervous system generates fast responses while the hormonal system generates slow and long responses.

Nervous Coordination
The centrel nervous sytem is the control centre of the body, where impulses are received and interpreted, and response impulses are sent to the relevant parts of the body for the appropriate responses.

The central nervous system communicates through electrical impulses, which are transmitted through interconnecting nerve cells.

Hormonal Coordination
The hormonal system consists of the endocrine glands, which secrete hormones. The blood system is involved in ensuring that hormones reach the target areas. The responses are usually projected in the form of growth, which is a slow response.

Penicillin vs Bacteria

Antibiotics can cure many disease. Penincilin was one of the first antibiotics discovered by Sir Alexander Fleming in 1928. It is produced by a species of the fungi Penicillium notatum, and has only been widely used from the 1940s.

During the Second World War, penicillin was dubbed a wonder drug; It was widely used to prevent death and amputations due to infected wounds.

Penicillin work buy inhibiting the formation of strong peptidoglycan cross-links in the bacterial cell wall. In other words, it weaken the cell wall of the bacterium. The bacterium then bursts due to pressure on its cell wall.

How Do Bacteria Die?

Microorganisms are sensitive to many physical or chemical agents. These agents are said to have a "bacteriostatic action" when they stop the growth of bacteria, and a "bactericidal action" when they kill them.

The sun, with its ultraviolet rays, is doubtless the oldest bactericidal agent, and one of the most efficient. Ultraviolet rays bring about mutations in bacteria, that is to say, changes in their genetic makeup, which prove to be deadly in most cases.

In general, bacteria are unable to develop in highly concentrated solutions of substances like sugar or salt. In such conditions, the water contained in the microorganisms is released through the cell wall in an attempt to dilute the medium outside (osmosis). The result is that the bacteria dehydrate and stop growing or die. This is what occurs when meat or fish is salted. Similarly, the presence of a large quantity of sugar in fruit jellies or jams helps to preserve them.

Heat is bacteria's mortal enemy. A temperature of 50 to 60 degrees Celsius (122 to 140 degrees Fahrenheit) for half an hour is sufficient to neutralize most bacteria, but those that can form spores require more stringent measures. It takes 20 minutes in a steam sterilizer to kill such germs. For this reason a surgeon's gown and the drapes over his patient are sterilized in such a manner.

Bacteria also are sensitive to many chemical substances. Knowledge of this can be put to good use in various ways, for example, in food preservation. The oldest and best-known chemical preservatives doubtless are alcohol and vinegar. More recently the chemical industry has created a wide variety of products acting either on bacteria or on fungi, and preventing their growth. Some of these chemical agents seem to be harmless, but unfortunately the long-term secondary effects of many of them are not known.

Variety Means Life

When you look at the world around you, have you ever wondered why there is so much diversity?

Studies suggest that there are between five and 100 million living species today. It sounds like a really big number but the truth is it is only a tiny fraction of all the species that have ever lived.

Species become extinct if they can't adapt quickly enough to circumstances or when competitor species dominate the present resources.

Ginkgo tree, Coelacanth fish and crocodiles have remained unchanged for millions of years that they are nicknamed 'living fossils'.

However, scientists believe most species exist for some 10 million years and then become extinct. This means just one in a thousand ever to exist remains living today.

Diversity is important for many reasons. In the short term, biodiversity is important because the bigger the range of living species, the more food, medicines, and natural resources we have.

High biodiversity also controls the spread of certain disease because viruses have to adapt to infect different species. Monoculture, growing just one species in one area, had led to many disasters.

For example, when Asia's rice farmers crops were destroyed by the Rice Grassy Stunt Virus in 1970s, scientists discovered only one out of 6,373 species of wild rice was resistant.

If there hadn't been so many alternatives available, rice crops may have suffered for decades. More importantly, as all lives on Earth are interconnected, biodiversity ensures we have fresh air, clean water and productive soils.

Now that so many species are threatened, we need to maintain as many different types of habitat as possible (ecological biodiversity), as many individual species as possible (genetic diversity) and as many kingdoms, phyla, and species (organismal diversity) as possible.

Food Safety

Food poisoning arises when we consume foods that are contaminated with bacteria like Salmonella and Escherichia coli, and their toxins.

Among the symptoms of food poisoning include nausea, vomiting, diarrhoea, abdominal cramps, fever and dehydration.

The symptoms usually appear six to 72 hours after the consumption of contiminated food.

Here are a few pointers for you to practise food safety.

* Scrub your hand clean! You don't want dirty hand touching your food.

* Veggies and fresh fruits like apples won't keep the doctor away if you don't wash them before eating them.

* Harmful microbes lurk in untreated water. Clean drinking water is what you should be downing.

* Raw meat can be loaded with harmful bacteria. Make sure the meat you eat is well-cooked.

*******
antibiotic : antibiotik
common cold : selsema
cough : batuk
diarrhoea : cirit birit
fermentation : penapaian
food poisoning : keracunan makanan
microorganism : mikroorganisma
nausea : muntah
yoghurt : dadih
*******