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.

Animal cell and plant cell

The cell is the basic unit of all organism. It is made up of a cell membrane that encloses the cytoplasm.


Contained within the cytoplasm are not only the nucleus but also organelles, whose specific functions help the cell perform a range of activities.

While plant and animal cells are similar, the plant cell has, in addition to the cell membrane, another boundary that separates it from its external environment. This is called the cell wall.

As most plant cells carry out photosynthesis - the synthesis of organic substances - they contain chloroplasts.

In plant cells, vacuoles also tend to be larger in size and smaller in number than those found in animal cells.


Onion Skin Cell


Cheek Squamous Epithelial Cells


Typical Plant Cell


Typical Animal Cell


In the laboratory, you have learned how to prepare a microscope slide of human cheek cells as well as the epidermal cells of onions.

a) The differences you can observe between the two types of cells in term of the following:

Shape
Onion cells have a regular shape while cheek cells have an irregular shape.


Presence or absence of cell wall
Onion cells have a cell wall while cheek cells do not.


Presence or absence of vacuoles
Onion cells have a large vacuole while vacuoles in cheek cells, if present, are small.

b) Can you observe chloroplasts in the epidermal cells of onions? Explain your answer.
No chloroplasts can be observed in the epidermal cells of onions because epidermal cells do not carry out photosynthesis.

Acid and Alkalis

Acids

Taste: Sour.
Touch: Like water.
Tested with litmus paper: Turn blue litmus red.
pH value: From 0 to less than 7.
Reaction with metals: Form hydrogen and a salt.
Reaction with carbonates: Form a salt, water and carbon dioxide.
Reaction with ammonium compounds: No reaction.

Alkalis

Taste: Bitter.
Touch: Soapy.
Tested with litmus paper: Turn red litmus blue.
pH value: From above 7 to 14.
Reaction with metals: No reaction.
Reaction with carbonates: No reaction.
Reaction with ammonium compounds: Give off ammonia gas.

Note: Strong acids and alkalis are corrosive and dangerous.

The Importantance Of Water

One of the most importance resources that the earth gives us is water. All living things, including humans, animals and plants, need water in order to survive.

While water is important to all living beings, it plays a different role for plants and for humans and animals. Let us differentiate the functions of water in human beings, animals and plants.

All the statements below tell us about the importance of water.

Importance of water to plants:

Water helps to support aquatic plants.
The process of transpiration involves water.
Water is needed for the germination of seeds.
Water helps to transport synthesised food to all parts of plant.
Water dissolves and transports mineral salts from the roots to the leaves.

Importance of water to human beings and animals:

Water dissolves and transports digested food to all parts of the living thing.
Water dilutes blood and enables it to transport oxygen efficiently.
A person will die of dehydration if he loses 20% of water from his body.
Water is important in excretion. It helps rid the body of unwanted substances.
Water controls body temperature.
Water keeps the lung moist for exchange of gases through respiration.
Water supports and maintains the body shape of invertebrates.
Water is needed in many household and daily activities.

Did you know?

70% of the earth's surface is covered in water.
Our body is made up of 60% to 95% of water.

Water is perhaps the most important nutrient in our diets. In fact, a human adult needs to drink approximately two litres (8 glasses) of water every day to replenish the water that is lost from the body through the skin, respiratory tract, and urine.


However, 99.7% of the Earth's water supply is not usable by humans. This unusable water includes salt water, ice, and water vapour in the atmosphere.

Only fresh water, which is contained in rivers, lakes, and underground sources, can be used for human consumption. Furthermore, many freshwater sources are not suitable for human to drink.

Water containing dangerous microorganisms and large amounts of industrial waste or agriculture chemicals (eg pesticides) can be toxic and unfit for drinking. Hence, humans have a great need for a reliable source of clean fresh water for drinking.

In addition to the water needed for drinking, other uses of fresh water include household use (eg cooking and cleaning), industry, agriculture (eg irrigation), and recreation.

Hence, the quality of fresh water supply is important for virtually every aspect of our lives. Water that is supplied for domestic use must be treated to ensure it is clean.

The water supplied must meet the National Guidelines for the Quality of Drinking Water (1983), which is based on the World Health Organisation (WHO) Guidelines for the Quality of Drinking Water (1984).

Air Components

The air in our atmosphere has some variable components to it as well. These variable components include water vapour, dust particles, and ozone. Although these are found in small amounts, they can have significant effects on weather and climate.

Water Vapour
The amount of water in the atmosphere varies between 1% to 4%. Why is such a small amount such a big deal? Water vapour is the source of all clouds and precipitation, and often that is the most common reason people think of for water. But water does other things too. It has the ability, like carbon dioxide, to absorb heat energy given off by the earth. It can also absorb solar energy. When water changes from one state to another, it absorbs or releases heat. This heat is often called latent (hidden) heat. This is the energy source that helps drives a lot of storms.

Dust
Dust is much more than just little specks of dirt. It includes microscopic particles that are invisible to the naked eye, including pollen, spores, and seeds. So why is dust a big deal? It acts as surfaces where water can condense or group together, forming clouds from which water droplets can grow large and fall to the ground as snow or rain. Without dust, you could not have clouds or fog. Dust can also absorb or reflect incoming solar radiation. When dust in the atmosphere is high, such as during the haze, the amount of sunlight reaching the earth's surface will decrease. Dust can also contribute to scattering light, giving rise to more orange and red sunrises or sunsets.

Other Gases
Methane, sulfur dioxide, hydrogen, nitrous oxide, nitrogen dioxide, iodine, carbon monoxide, ammonia.

Microorganisms
Bacteria, fungi, viruses.

Ozone
Ozone is a form of oxygen that combines three oxygeb atoms into one molecule (O3). There is very little of this gas in the atmosphere, and it is concentrated in the stratosphere. Ozone absorbs ultraviolet (UV) radiation, and without it the earth would be uninhabitable. There may be other components depending on the quality or condition of the air.

Basic Components Of Air

Nitrogen (N2)
The rather non-reactive nature of nitrogen balances the active nature of oxygen in air. It is also converted to plant nutrients by lightning and certain soil bacteria. Nitrogen is important to life processes. It is the backbone of amino acids, which are the building blocks of protein for all living things. Without nitrogen, even plants cannot maintain their structures.

Oxygen (O2)
Highly reactive; it is needed by all living things for respiration, that is to metabolise food into energy and excrete carbon dioxide gas. Without oxygen, we would be dead in minutes!

Inert Gases
Totally non-reactive gases like argon (Ar) 0.94%, hydrogen (H) 0.01%, neon (Ne) 0.012%, helium (He) 0.0005%, krypton (Kr) 0.0001%, xenon (Xe) 0.000009%.

Carbon Dioxide (CO2)
This gas is a product of respiration & combustion. Plants take in this gas through their leaves, keep the carbon portion of it and excrete the oxygen back into the environment through a process called photosynthesis. This gas has the ability to absorb radiated heat and thus, helps to keep the atmosphere warm.

Dari Seorang Sahabat

Jika kamu memancing ikan, setelah ikan itu terlekat di mata kail, hendaklah kamu mengambil terus ikan itu. Janganlah sesekali kamu lepaskan ia semula ke dalam air begitu sahaja. Kerana ia akan sakit oleh kerana bisanya ketajaman mata kailmu dan mungkin ia akan menderita selagi ia masih hidup.

Begitulah juga setelah kamu memberi banyak pengharapan kepada seseorang. Setelah ia mula menyayangimu hendaklah kamu menjaga hatinya. Janganlah sesekali kamu terus meninggalkannya begitu sahaja. Kerana dia akan terluka oleh kenangan bersamamu dan mungkin tidak dapat melupakan segalanya selagi dia mengingatimu.

Jika kamu menadah air biarlah berpada, Jangan terlalu mengharap pada takungannya dan janganlah menganggap ia begitu teguh. Cukuplah sekadar keperluanmu. Apabila sekali ia retak, tentu sukar untuk kamu menampalnya semula. Akhirnya ia dibuang. Sedangkan jika kamu cuba membaikinya mungkin ia masih boleh digunakan lagi.

Begitu juga jika kamu memiliki seseorang terimalah seadanya. Janganlah kamu terlalu mengaguminya dan janganlah kamu menganggapnya begitu istimewa. Anggaplah dia manusia biasa. Apabila dia melakukan kesilapan bukan mudah bagi kamu untuk menerimanya. Akhirnya kamu kecewa dan meninggalkannya. Sedangkan jika kamu memaafkannya boleh jadi hubungan kamu akan berterusan hingga ke akhirnya.

Jika kamu telah memiliki sepinggan nasi, yang kamu pasti baik untuk dirimu. Mengenyangkan dan berkhasiat. Mengapa kamu berlengah cuba mencari makanan yang lain. Terlalu ingin mengejar kelazatan. Kelak, nasi itu akan basi dan kamu tidak boleh memakannya. Kamu akan menyesal.


Begitu juga jika kamu telah bertemu dengan seorang insan, yang kamu pasti membawa kebaikan kepada dirimu. Menyayangimu dan mengasihimu. Mengapa kamu berlengah, cuba membandingkannya dengan yang lain. Terlalu mengejar kesempurnaan. Kelak kamu akan kehilangannya dan apabila dia menjadi milik orang lain kamu juga yang akan menyesal.

"apabila dia pergi barulah kita tahu bahawa ia bernilai utk kita"