Magnesium

When it was discovered?

It was discovered in year 1808.

By whom it was discovered?

In 1755, Joseph Black, a Scottish found out that magnesium was its own compound by examining two compounds of magnesia and lime (calcium carbonate. Sir Humphrey Davy separated magnesium into its own element in 1808. He used the method “electrolysis” to a mixture of magnesium oxide and mercuric oxide and heated the compound in a tube to take away mercury, which left pure magnesium behind. Antoine A.B. Bussy was a French chemist who found a way to isolate magnesium in large quantities. He heated magnesium chloride and potassium which formed potassium chloride, which he then remove from the tube, and that left small globules of magnesium. Most people said that Sir Humphrey Davy discovered magnesium probably because he was able to isolate it and which made it useful.

How it is found in nature?

Magnesium’s ions are vital in all living things. It is the eighth-most abundant element in the Earth's crust and it is the second-most plentiful ion in seawater. Most of the magnesium is acquired by electrolysis of fused magnesium chloride, which is found in sea water, brines, or wells.

What are its properties and uses?

Magnesium’s symbol is Mg, its atomic number 12. It is a good conductor of heat and electricity and has uses apart from being used as antacids and forming the bright light in fireworks.

Magnesium is essential for over 300 processes in your body. Basically, it causes everything to function better: bones, digestion, muscles, and nerves. Fatigue, muscle weakness and migraines could be some consequences for the absence of magnesium in our body. More severe illnesses include high blood pressure, asthma, osteoporosis, glaucoma and less effective immune system. Half of human’s body's magnesium is found in bones, with others found in cells and 1% in blood. Magnesium is also vital for plants. It is an important element in the chlorophyll molecule.

So, in gardening and farming, magnesium sulfate can be used to richen soil that lacks magnesium. Because magnesium emanates a bright light when burned, magnesium is used in fireworks, flares and bombs. It is also included in rocket and missile fuels. Magnesium is also an element of flash light powders used in photography. Another main use of magnesium is avoiding corrosion of steel and iron. This is particularly handy in pipelines and the bottom of ships; these materials are electrically coated with magnesium. Since magnesium oxidizes rapidly and iron oxidizes gradually, mixing magnesium and iron together prevents iron from rusting and corroding. Since magnesium is lighter than aluminum, it is suitable as an alloy. It makes other metals lighter and more simply welded, machined or cast. Other than being used in aircraft, wheels, engine parts, and missiles, magnesium is also used in computers for radio-frequency shielding. Mixing aluminum with magnesium makes beverage cans. It is also used as a reducing agent in the manufacturing of pure uranium and other metals from their salts. The hydroxide (milk of magnesia), chloride, sulfate (Epsom salts), and citrate are used in medicine. Dead-burned magnesite is used in bricks and liners in furnaces and converters.

Sources:

http://answers.yourdictionary.com/science/who-discovered-magnesium.html

http://periodic.lanl.gov/elements/12.html

http://en.wikipedia.org/wiki/Magnesium

Excursion Trip: Spiny Hill Terrapin Encounter

Go to site: https://sites.google.com/site/scienceeport/home/spiny-terrapin-encounter and click on

the attachments below.

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Short-sightedness and Long-sightedness

Go to site: https://sites.google.com/site/scienceeport/home/short-sightedness-and-long-sightedness and click on the attachment below.

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Allomerus decemarticulatus ants

(a) Deforestation is an example for human activities in the Amazon Forest. When building homes, factories etc. land is reclaimed and forests are normally burned down. Between May 2000 and August 2006, over 600,000 square kilometers of Amazon rainforest has been destroyed. Brazilian deforestation is strongly associated to the economic health of the country.

A relatively small percentage of large landowners clear vast sections of the Amazon for cattle pastureland. Large areas of forest are cleared and sometimes planted with African savanna grasses for cattle feeding. In many cases, especially during periods of high inflation, land is simply cleared for investment purposes. When pastureland prices exceed forest land prices, forest clearing is a good hedge against inflation.

Such favorable taxation policies, combined with government subsidized agriculture and colonization programs, encourage the destruction of the Amazon. The practice of low taxes on income derived from agriculture and tax rates that favor pasture over forest overvalues agriculture and pastureland and makes it profitable to convert natural forest for these purposes when it normally would not be so.

Up until at least the mid-1990s this system was worsened by the government policy that allowed each claimant to gain title for an amount of land up to three times the amount of forest cleared. A significant amount of deforestation is caused by the subsistence activities of poor farmers who are encouraged to settle on forest lands by government land policies. Poor farmers use fire for clearing land and every year satellite images pick up tens of thousands of fires burning across the Amazon, which burns the Allomerus decemarticulatus ants to death immediately.

Logging in the Amazon is closely linked with road building. Studies by the Environmental Defense Fund show that areas that have been selectively logged are eight times more likely to be settled and cleared by shifting cultivators than untouched rainforests because of access granted to logging roads. Logging roads give colonists access to rainforest, which they exploit for fuelwood, game, building material, and temporary agricultural lands, further destroying the habitat of the Allomerus decemarticulatus ants.

Furthermore, hydroelectric projects have flooded vast areas of Amazon rainforest. The Balbina dam flooded some 2,400 square kilometers (920 square miles) of rainforest when it was completed. This would drown the Allomeerus decemarticulatus ants.

Therefore, this displaces animals, including the Allomerus decemarticulatus ants. Furthermore, as their food source largely depends on making traps using plants to capture insects, deforestation would also mean the loss of traps; hence the ability to capture its prey also decreases tremendously. This will result in the lack of food source for the Allomerus decemarticulatus ants and cause a decrease in its population eventually. Therefore, with no food, the population figures will drop.

(b) The plant is protected by the ants, since the Allomerus decemarticulatus ants capture the insects which might to eat the plant. The plant provides shelter and a platform for the Allomerus decemarticulatus ants to catch prey. Both party benefits. – Mutualism. ***

Mould would benefit since the Allomerus decemarticulatus ants would provide protection for it and sustain it (place to grow) whereas the Allomerus decemarticulatus ants would also benefit since it could catch its prey effectively – thus, since both parties benefit, this proves to be mutualism instead of commensalism or parasitism. – Mutualism.

Mould grows around structure of the plant, but does not affect it. However, the mould in turn finds a place to inhabit. – Commensalism.

When an insect passes overhead, the ants reach up and grab its free legs, wings and antennae, stretching it against the gallery… Swarms of workers then rush over the hapless prey, stinging it into submission. – Exploitative relationship: Predation.

The host farm provides protein, and it has to be shared between the Allomerus decemarticulatus ants and the mould. – Competition.

*** Though not exactly the same, this is similar to the red weevil ants and the macaranga plants or the senduduk plants in Singapore. The macaranga and senduduk plants provide nutrients for ants, and the ants in turn defend the tree from other harmful organisms. While it seems that it is only ants that protect plants from damage, some plants also protect ants. In Singapore, there are palms filled with thorns, and black-coloured ants inhabit it. Thorns in palms would protect ants from predators since predators could not get close to the ants, whereas the ants would too provide protection from palms, since it defend the palms from organisms such as parasites.
References:
http://peeepl.com/gate/index.html?people_id=73801305&to=http%253A%252F%252F2a2science.blogspot.com%252F2011%252F05%252Fhbl-benedict-chin-2a206.html
http://www.mongabay.com/brazil.html
http://2a2science.blogspot.com/

`Toxin free farming - with friendly insects'

Read the newspaper article below and answer the questions below.
Questions



a. Why is Paul Buxman critical of the way some farmers deal with the control of pests?

Paul Buxman feels that farmers should not monitor pesticides by using chemicals fully, since he himself has used not harmful chemicals for nine years since his son developed leukaemia. He did this also because groundwater tests showed chemical levels is 20 time US health levels, and he wanted to prevent this, by using a healthier method of pest monitoring. Also, soil fertility is built naturally by growing cover crops, spreading manure and compost.

b. What is 'integrated pest management'? Is it labour¬-saving or more labour-intensive?

‘Integrated pest management’ is an integrated approach of crop management to solve ecological problems when applied in agriculture. These methods are performed in three stages: prevention, observation, and intervention. It is an ecological approach with a main goal of significantly reducing or eliminating the use of pesticides while at the same time managing pest populations at an acceptable level. This is more labour-intensive than pure chemical usage, since the involvement organic farming requires manpower to monitor the pests.

c. How do insecticides affect bird and worm numbers?

Insecticides decrease the bird and worm numbers.

d. What is meant by `organic farming'?

‘Organic farming’ is the form of agriculture that relies on techniques such as crop rotation, green manure, compost and biological pest control to maintain soil productivity and control pests on a farm.

e. What 'balance of pests and predators' is the article talking about?

The ‘balance of pests and predators’ means that the number of pests and predators are in proportion to what the pyramid of numbers would be like in the natural environment. For example, spiders, ladybugs, praying mantis and the six-spotted thrips (or the predators) would be there to feed on pests such as aphids and mites, while the lacewing eats larvae four times its weight in pests every week.

f. What is meant by `broad spectrum fertilisers'?

‘Broad spectrum fertilisers’ is meant by fertilisers that are effective against a wide variety of microorganisms.

References:
http://bbe-tech.com/bees/2011/06/14/how-does-integrated-pest-management-work-for-you/
http://en.wikipedia.org/wiki/Organic_farming
http://en.wikipedia.org/wiki/Integrated_pest_management
http://www.yourdictionary.com/broad-spectrum

Reflection: Term 3 test results

The recent result I received was 32.5/40, again, an A1 that barely meet the requirements. The test topics ranged from biology to physics, with ecology and refraction and total internal reflection of light, which is combination of facts and application types of questions.

This time, due to time constraint, I had no choice but to compromise my science revision time for other subjects such as Integrated Humanities. As a matter of fact, because my science test is one day right after my Integrated Humanities, and that Integrated Humanities required much more memorization work, I planned that I should only leave one day for my revision for science – in other works, my revision this time was sort of a last minute kind.

However, I already had quite a sufficient understanding on the physic topics due to listening intently during class time, and also because physics mainly required us to think and draw. Either that or we needed to perform some mathematics functions which required the involvement of trigonometry, or the sine, cosine and tangent, in which I quite good at. Therefore, that leaves me with some memorizing work for ecology. I did not actually had quite enough time for practicing, which to me definitely is not negligible, but I had no choice but to make do with it.

As a matter of fact, the main problems I faced in this test is because I did not have enough time to do the bonus question, which many of my classmates obtained marks from. Perhaps, it is because I did not practice enough for my test, thus being slow and insensitive to the methods used to solve trivial questions, thus wasting unnecessary time. There was again careless mistakes, and another blatant error due to not reading the question properly, thus missing out the naming of symbols in a ray diagram.

It was a low A1, but well, at least I managed to maintain my standard!

Excursion trip to Nee Soon Swamp Forest

Go to site: https://sites.google.com/site/scienceeport/home/excursion-trip-to-nee-soon-swamp-forest and click on the attachments below to see my excursion trip to Nee Soon Swamp Forest.

Due to some technical difficulties, the alignment of the pictures and words are not in proper. Sorry for the inconvenience caused.

Sulfuric Acid

General background:

Sulfuric acid is a chemical compound H2SO4 that is colorless, odorless, extremely corrosive, oily liquid and is sometimes called oil of vitriol. Balanced equation: H2SO4  H2 + SO42−


Uses of sulfuric acid:

1. Serves as electrolyte in lead-acid storage battery.
a. Acid for this use, containing about 33% H2SO4 and with specific gravity about 1.25, is often called battery acid.
b. Commonly used in motor vehicles.
2. Crucial in the production of fertilizers.
a. Examples: Superphosphate of lime (CaCO3) and ammonium sulfate (NH4)2SO4, which is formed when rock phosphate is treated with sulfuric acid.
3. Used to remove oxides and rusts from iron and steel before plating them with tin or zinc.
4. Dehydrating agent to remove water (only for concentrated sulfuric acid).
a. It has a tendency to form hydrates such as H2SO4.H2O, H2SO4.2H2O, etc.
5. Used to dry neutral and acidic gases.
a. Examples: Nitrogen gas N2, Oxygen gas O2, Carbon dioxide CO2, Sulfur dioxide SO2 etc.
6. Remove water from carbohydrates and some other organic compounds which contain oxygen and hydrogen.
a. Examples: React with sucrose or cane sugar C12H22O11(s) to produce a spongy mass of carbon:
i. C12H22O11(s) + 11H2SO4 12C(s) + 11H2SO4.H2O
7. Used in production of nitroglycerine, an inorganic ester and organic nitrate.
a. Used as an explosive.
b. Used as a vasodilator that is a substance that dilates blood vessels and can be used in the treatment of certain types of heart disease.
8. Used in petroleum refining to wash impurities out of gasoline and other refinery products.
9. Used to make rayon.
10. Use in the manufacturing of other chemicals.
a. Examples: hydrochloric acid, nitric acid, sulfate salts, synthetic detergents, dyes and pigments, explosives, and drugs.


Manufacture of sulfuric acid:

General background: There are two major processes in the manufacturing and production of sulfuric acid, namely the Lead Chamber Process and the Lead Contact Process, with the Lead Chamber Process being the older of the two. The Lead Chamber Process is used to produce much of the acid used to make fertilizers and produces a relatively dilute acid of 62%–78% sulfuric acid whereas the contact process produces a much purer, more concentrated acid but requires purer raw materials and the use of expensive catalysts. Both processes are similar in the oxidized of sulfur dioxide and the dissolving of sulfur dioxide in water.

1. Lead Chamber Process

History

In 1746 John Roebuck developed the Lead Chamber Process for the manufacture of sulfuric acid. Prior to this time, sulfuric acid had been produced in glass bottles several pounds at a time. But the lead chamber process could produce sulfuric acid by the ton. However, this manufacturing process was a batch process and resulted in the consumption of potassium nitrate. In 1835, Joseph Gay-Lussac improved the manufacturing process.


Process

John Roebuck’s Lead Chamber Process:
a) In the original lead chamber process, sulfur and potassium nitrate are ignited in a room lined with lead foil. Potassium nitrate, or saltpeter is an oxidizing agent oxidizes the sulfur to sulfur trioxide.
a. Chemical equation: 6 KNO3(s) + 7 S(s) -----> 3 K2S + 6 NO(g) + 4 SO3(g)
b) The floor of the room was covered with water. When the sulfur trioxide reacted with the water, sulfuric acid was produced.
a. SO3(g) + H2O(l) -----> H2SO4(aq)

Joseph Gay-Lussac’s improvement:
a) A process for recovering the nitrogen in nitrogen monoxide and recycling it to replace the saltpeter as a source of nitrogen was invented.
a. Chemical equation: 4 NO(g) + O2(g) + 2 H2O(l) -----> 4 HNO2(l)
b. Chemical equation: 4 HNO2(l) + 2 SO2(g) -----> 2 H2SO4(aq) + 4 NO(g)
b) Reduced the dependence on expensive saltpeter and sharply reduced nitrogen monoxide emissions.

Lead Chamber Process after improvements:
a) Hot sulfur dioxide gas enters the bottom of a reactor called a Glover tower where it is washed with nitrous vitriol (sulfuric acid with nitric oxide and nitrogen dioxide dissolved in it) and mixed with nitric oxide and nitrogen dioxide gases.
a. Two functions of the Glover tower:
i. Concentration of the chamber acid (62% to 68% H2SO4) is achieved by the hot gases entering the tower which evaporate water from the acid. Some of the sulfur dioxide is oxidized to sulfur trioxide and dissolved in the acid wash to form tower acid or Glover acid (about 78% H2SO4).
ii. Dissolved nitrogen oxides are stripped from the acid and carried with the gas out of the Glover tower into the lead chambers.
b) From the Glover tower, a mixture of gases – including sulfur dioxide and trioxide, nitrogen oxides, nitrogen, oxygen, and steam – is transferred to a lead-lined chamber where it is reacted with more water.
a. Lead-lined chamber: A large, boxlike room or an enclosure in the form of a truncated cone.
b. Sulfuric acid condenses on the walls and collects on the floor of the chamber.
c. The gases pass through each in succession of the three to twelve chambers in a series.
d. The acid produced in the chambers, often called chamber acid or fertilizer acid, contains 62% to 68% H2SO4.
e. Chemical equation: 2 SO2 + O2 + 2 H2O -----> 2 H2SO4
c) After the gases have passed through the chambers they are passed into a reactor called the Gay-Lussac tower where they are washed with cooled concentrated acid from the Glover tower.
a. The nitrogen oxides and unreacted sulfur dioxide dissolve in the acid to form the nitrous vitriol used in the Glover tower.
b. The waste gases exiting the Guy-Lussac tower are usually discharged into the atmosphere.
d) Product acid at a concentration of 78% H2SO4 is drawn from the cooled acid stream that is circulated from the Glover tower to the Guy-Lussac tower. Nitrogen losses are made up with nitric acid which is added to the Glover tower.



2. Contact Process: A process involving the catalytic oxidation of sulfur dioxide, SO2, to sulfur trioxide, SO3.

History

The first observation of a “contact” or heterogeneous catalytic reaction seems to have been made by Edmund Davy in 1817. He noted that heated platinum wire introduced into a mixture of oxygen or air with hydrogen, carbon monoxide, or ethylene became hotter and finally glowed with rapid combustion of the mixture. In 1831 Peregrine Phillips, a vinegar manufacturer in Bristol, England, patented a new process in British Patent No. 6096. The patent described the instantaneous union of sulfur dioxide with atmospheric oxygen when passing the mixture over platinum which had been heated to a strong yellow heat, with the sulfur trioxide formed rapidly absorbed when contacted with water to form sulfuric acid. In spite of the obvious advantages of the contact process over chamber plants for the production of high strength sulfuric acid and oleum used for dyes and nitrocellulose (smokeless powder), the commercial development of the process was extremely slow. Chemical technology of the time, especially involving catalytic reactions, was limited.

Process

a) Solid sulfur, S(s), is burned in air to form sulfur dioxide gas, SO2.
a. Chemical equation: S(s) + O2(g)  SO2(g)
b) The gases are mixed with more air then cleaned by electrostatic precipitation to remove any particulate matter.
c) The mixture of sulfur dioxide and air is heated to 450oC and subjected to a pressure of 101.3 - 202.6 kPa (1 -2 atmospheres) in the presence of a catalyst, which is often platinum on a silica/ asbestos carrier/ vanadium pentoxide on a silica carrier (vanadium oxide) to produce sulfur trioxide, SO3(g), with a yield of 98%.
a. Chemical equation: 2SO2(g) + O2(g)  2SO3(g)
d) Any unreacted gases from the above reaction are recycled back into the above reaction.
e) The sulfur trioxide is cooled and passed through two towers.
a. In the first tower, sulfur trioxide, SO3(g) is dissolved in 98% sulfuric acid, H2SO4, to produce disulfuric acid or pyrosulfuric acid, also known as fuming sulfuric acid or oleum, H2S2O7.
i. Chemical equation: SO3(g) + H2SO4 ------> H2S2O7
ii. This is done because when water is added directly to sulfur trioxide to produce sulfuric acid.
iii. Chemical equation: SO3(g) + H2O(l) -----> H2SO4(l)
iv. The reaction is slow and tends to form a mist in which the particles refuse to coalesce (bond).
v. Note: This cannot be done by simply adding water to the sulphur trioxide – the reaction is too uncontrollable that it creates a fog of sulphuric acid.
b. Water is added to the disulfuric acid, H2S2O7, to produce sulfuric acid, H2SO4
c. Chemical equation: H2S2O7(l) + H2O(l) -----> 2H2SO4(l)
d. Note: This can then be reacted safely with water to produce concentrated sulphuric acid - twice as much as you originally used to make the fuming sulphuric acid.



References:
http://www.ausetute.com.au/sulfacid.html
http://www.infoplease.com/ce6/sci/A0861350.html
http://www.infoplease.com/ce6/sci/A0861351.html
http://www.chemguide.co.uk/physical/equilibria/contact.html
www.aiche-cf.org/Clearwater/2008/Paper2/8.2.7.pdf
http://en.wikipedia.org/wiki/Sulfuric_acid
http://web.fccj.org/~ethall/h2so4/h2so4.htm
http://scifun.chem.wisc.edu/chemweek/sulf&top/sulf&top.html
http://www.factmonster.com/ce6/sci/A0861351.html
http://www.factmonster.com/ce6/sci/A0861350.html
http://www.buzzle.com/articles/sulfuric-acid-uses.html

Development of the Periodic Table

Attempts made by Johann Wolfgang Döbereiner:


The development of the periodic table begins with German chemist Johann Wolfgang Döbereiner (1780-1849) who grouped certain elements based on similarities and anticipated the development of the periodic system of elements, such as grouping the group I (alkali metal) elements lithium, sodium and potassium together for being soft, reactive metals. He also noticed other patterns in the group I elements, such as all react with water at room temperature and react with chlorine to form compounds with similar formulas: LiCl, NaCl, and KCl, combine with hydrogen to form compounds with similar formulas: LiH, NaH, and KH and form hydroxides with similar formulas: LiOH, NaOH, and KOH.

Döbereiner recalled a comparable graduation of properties in two other sequences—calcium, strontium, barium; and sulfur, selenium, tellurium. Calcium (atomic weight 40), strontium (atomic weight 88), and barium (atomic weight 137) possess similar chemical prepares and Döbereiner noticed the atomic weight of strontium fell midway between the weights of calcium and barium:

Calcium (Ca) Strontium (Sr) Barium (Ba)
40 88 137

(40 + 137) ÷ 2 = 88

Dobereiner also noticed the same pattern for the alkali metal triad, lithium (Li), sodium (Na) and potassium (K) and the halogen triad, chlorine (Cl) Bromine (Br) and Iodine (I). Furthermore, Dobereiner found that the density of the middle element in most triads is roughly equal to the average of the densities of the other elements. The density of strontium (2.60 g/cm3), for example, is close to the average of the densities of calcium (1.55 g/cm3) and barium (3.51 g/cm3).

In 1829, Dobereiner proposed the Law of Triads: Middle element in the triad had atomic weight that was roughly the average of the other two members. Soon other scientists found chemical relationships extended beyond triads. Fluorine was added to halogen group; sulfur, oxygen, selenium and tellurium were grouped into a family; nitrogen, phosphorus, arsenic, antimony, and bismuth were classified as another group.



Attempts made by John Alexander Reina Newlands:

English chemist John Alexander Reina Newlands (1837-1898), having arranged the 62 known elements in order of increasing atomic weights, noted that after interval of eight elements similar physical/chemical properties reappeared.

Newlands was the first to formulate the concept of periodicity in the properties of the chemical elements. In 1864 and 1865, he wrote a series of papers proposing the Law of Octaves which stated that any given element will exhibit analogues behaviour to the eighth element following it in the table. In other words, when he listed in order of increasing atomic weight, similar physical and chemical properties recurred at intervals of eight, which he likened to the octaves of music. However, Newlands was so enthralled with this "law of octaves" that he made the mistake of trying to force the elements into this pattern.


Newlands’ Octave:
H Li Ga B C N O
F Na Mg Al Si P S
Cl K Ca Cr Ti Mn Fe
Co,Ni Cu Zn Y In As Se
Br Rb Sr Ce,La Zr Di,Mo Ro,Ru
Pd Ag Cd U Sn Sb Te
I Cs Ba,V Ta W Nb Au
Pt,Ir Tl Pb Th Hg Bi Cs


The elements are ordered by atomic weights that were known at the time. They were numbered sequentially to show the order of atomic weights. In Newlands’ table, periods and groups are shown going down and across the table, respectively – the opposite from the modern periodic table.

The incompleteness of a table he drew up 1864 attributed to the possible existence of additional, undiscovered elements. For example, he predicted the existence of germanium.

However, there are obvious problems with Newlands' table of the elements. The first row, for example, group elements with similar chemical properties such as Fluorine, Chlorine, Bromine and Iodine, but it also includes elements that have totally different chemical properties such as Cobalt, Nickel, Palladium, Platinum and Iridium. Furthermore, at a time when elements were being discovered with some regularity, Newlands failed to leave room in his table for new elements.





References:
http://www.britannica.com/EBchecked/topic/167249/Johann-Wolfgang-Dobereiner
http://web.fccj.org/~ethall/period/period.htm
http://www.eoht.info/page/Johann+Dobereiner
http://www.corrosion-doctors.org/Periodic/Periodic-Dobereiner.htm
http://en.wikipedia.org/wiki/Johann_Wolfgang_Döbereiner
http://chemed.chem.purdue.edu/genchem/history/dobereiner.html
http://en.wikipedia.org/wiki/John_Alexander_Reina_Newlands
http://www.nndb.com/people/480/000103171/
http://dl.clackamas.cc.or.us/ch104-07/newlands.htm
http://www.britannica.com/EBchecked/topic/412978/John-Alexander-Reina-Newlands

Dragonfly walk to Venus Drive

I would deem myself as quite passionate in dragonfly and since 5-year old, I had already started observing dragonfly. Therefore, I have a decent amount of knowledge to lead a walk on dragonflies. The weather was very good that day, with the sun hanging in the sky that shone brightly onto the stream, making the stream sparkle......Though it was a little bit hot, it was a perfectly good day for dragonfly-watching as dragonflies are cold-blooded and they need to warm up in the Sun to be active.
There was a lot of habitats in Venus trail, including mud patches, streams, ponds, shady stagnant pools...and from all these habitats, we could find a certain amount of dragonfly species. The day started off very good, because in the open stream, which was expected to have lesser species as it is not in the forest, turns out quite good as we spotted around 10 species. Though all of them are just common species, the people which participated in the walk are still very impressed by the colours of the dragonflies as they did not take a good look at these species before. In addition, we also found some common species mating, like the ceriagrion cerinorubellum and the Orthetrum Chrysis. (Sorry for using latin names as I am not really sure with the common names, as I just got to know the names about a few months ago)
A surprise was in store for us later when we went into the forest. On a stagnant pool, I spotted a Gynacantha dohrni hovering over a stagnant pool. This species is a crepuscular species that is rarely spotted in the morning unless we bashed into the dense bushes. Though it was a less seen species, it is dull green in colour and the colour is not very striking. Therefore, I was not very sure if the people who attended the talk knew really appreciated it. Around the stagnant pool, we also spotted a special damselfly that opened it's wings when rested instead of opening. Other than that, we also spotted a blue-red-and-yellow species that was quite rare as it mostly appeared in the Central Catchment area.
As we continued to a forest stream, we spotted two big metallic green damselfly that was fluttering under the sun, it's wings shimmering with blue. This two damselfly was displaying and flying facing each other. However, it is a very secretive species and not long after, it flew down the stream and disappeared. Therefore, only a few people saw this species.
Lastly, as we continued to a pond, we also spotted a few species mating. The damselflies mate in a way that a heart-shape was form when they attached their appendages and ovipositors to each other and after mating, we saw them ovipositing in the Tandem guarding method, which is the male's appendage hooked to the female's thorax while it is ovipositing. The dragonflies flew around together, and they practiced Non-contact guarding, which was the male hovering above, guarding the female while the female is ovipositing in the water.
At last, we came to the end of the walk, which was very sastifactory. Overall, we spotted 22 species, which was around 1/6 of the total dragonflies in Singapore (125 species in Singapore, with the recent discovery of zyxomma obtusum in Pulau Ubin).

Sea level rising

Global warming is causing the earth's temperature to rise about half a degree Celsius in the past 100 years. Half a degree might seem to you to be just a very small number, however, it is big enough to affect our planet.The main ice could be found at Antarctica, which is at the South Pole, with about 90 percent of the world's ice and 70 percent of its fresh water. Antarctica is covered with ice an average of 2,133 meters. If all of the Antarctic ice melted into the vast sea, sea levels around the world would rise about 61 meters. But the average temperature in Antarctica is -37°C, so the ice there is in no danger of melting. But there might be a less shocking reason than polar ice melting for the higher ocean level -- the higher temperature of the water. Water is most dense at 4 degrees Celsius. Whether the temperature is higher or lower, the density of water would decrease. So as the overall temperature of the water is rising, it naturally expands a little bit making the oceans level increase. Researches had estimate that the sea will rise 50 centimeters with the lowest estimates at 15 centimeters and the highest at 95 centimeters. The rise of the sea level will come from the melting glaciers and ice sheets which are caused by the gradually increasing temperature of the planet. Could you imagine if the Polar Caps rises until it covers the whole Singapore? I hope it would not work out this way. Therefore, the message to learn from this rising of sea level is start conserving now!

Process of making NEWater

NEWater is a reclaimed sewage but it would be ready to be drank after going through 4 barriers of disinfection and additional chemicals.
The 1st barrier will make used water treated to globally recognised standards in the Water Reclamation Plants.
In the 2nd stage, the suspension is filtered using membranes. The residue would be the suspended solids, colloidal particles, disease-causing bacteria, some viruses and protozoan cysts. The filtrate contains only dissolved salts and organic molecules.
The 3rd stage is known as Reverse Osmosis in which a semi-permeable membrane is used. Only small molecules like water molecules to pass through as the membrane has only very small pores and contaminants cannot pass through the membrane.
Lastly, ultraviolet or UV disinfection is used to ensure that all organisms are inactivated. Then, some alkaline chemicals are added to restore the pH balance. The last step acts as a precaution and all is done.

Recycling Paper

Everybody has to play a part in conservation and saving the Earth. We can contribute just by doing very simple things, like recycling paper. As you know, Earth is facing a very great problem: Global Warming. This resulted in the rise of the temperature and the Polar Caps are melting very rapidly. One of this problems is because people are cutting down too many trees to make paper.

Once the paper is transported into a factory, the paper os being sorted, graded and delivered to a paper mill. Water would be added to the recycled paper and turning it into a pulp. The paper is then screened, cleaned and de-inked through a number of processes until it is suitable for paper making. It is then ready to be made into new paper products such as newsprint, cardboard, packaging, tissue and office items. Seven days is needed for a newspaper to go through the recycling process and be transformed into recycled newsprint.

As you can see, the process of recycling paper is easy. Therefore, why don't everybody come and cooperate by throwing paper into recycling bin instead of throwing into a normal rubbish bin which makes factory workers very hard to extract?

Reflection: Term 2 test results

The second term test is about acids, bases and salts, and reflection of light on plane mirror. This time, not only did I compile and memorise the facts, I also did a lot of practices so as to gain exposure and have a better understanding on would be tested in the test. I found that to be able to score well for both these topics on chemistry and physics, I needed to have the ability to foresee which type of questions would exactly come out in the test, and be able to apply the rules I learnt in the questions.

I find acids, bases and salts, a topic that is greatly logical – or in other words, it requires the student to be able to have basic mathematics calculation skills of addition and subtraction. For example, the way protons and electrons stabilize one another complicates the matter in

This time, to my elation, I obtained exceedingly excellent results. Not only was it an A1, it was a high A1 – 37.5/40. Yet, I did not get the highest score in the class this time, though it was only 2.5 marks from the full marks. The highest score in class was a whopping 39/40, which translates to 97.5/100. I admit that the paper was relatively easy, and it is indeed possible to achieve such stunning results, however, I have to agree that it is nonetheless extremely difficult to get this mark – to allow hardly any error except only 1 mark deducted from the test was almost impossible. Well, but for myself, I felt quite satisfied with my results – especially feeling very satisfied after putting in so much hard work and effort. The sense of achievement was great, and I felt grateful that my efforts were not futile.

Building Muscle Doesn't Require Lifting Heavy Weights, Study Shows:

Article from www.sciencedaily.com:The findings are published in PLoS ONE.
"Rather than grunting and straining to lift heavy weights, you can grab something much lighter but you have to lift it until you can't lift it anymore," says Stuart Phillips, associate professor of kinesiology at McMaster University. "We're convinced that growing muscle means stimulating your muscle to make new muscle proteins, a process in the body that over time accumulates into bigger muscles."
Phillips praised lead author and senior Ph.D. student Nicholas Burd for masterminding the project that showed it's really not the weight that you lift but the fact that you get muscular fatigue that's the critical point in building muscle. The study used light weights that represented a percentage of what the subjects could lift. The heavier weights were set to 90% of a person's best lift and the light weights at a mere 30% of what people could lift. "It's a very light weight," says Phillips noting that the 90-80% range is usually something people can lift from 5-10 times before fatigue sets in. At 30%, Burd reported that subjects could lift that weight at least 24 times before they felt fatigue.
"We're excited to see where this new paradigm will lead," says Phillips, adding that these new data have practical significance for gym enthusiasts but more importantly for people with compromised skeletal muscle mass, such as the elderly, patients with cancer, or those who are recovering from trauma, surgery or even stroke.

Reflections: I was very surprised and shocked after I read this article. The article stated that a new study conducted at McMaster University has shown that a similar degree of muscle building can be achieved by using lighter weights. You just need your muscles to feel fatigue, and you would have your muscles. However, the bad thing is that you need to raise the weight more times. This research also says that other than having practical significance for gym enthusiasts, it would also benefit people with compromised skeletal muscle mass, such as the elderly, patients with cancer, or those who are recovering from trauma, surgery or even stroke. Therefore, I think that these new discovery benefits humans a lot and I would not need to train so hard to get muscles as light weights could also do! However, one still need to put in effort to train muscles as you would also need more time to train muscles in the new method as you need to raise lighter weights more times!

Free Statins With Fast Food Could Neutralize Heart Risk, Scientists Say:

Article from www.sciencedaily.com: Statins reduce the amount of unhealthy "LDL" cholesterol in the blood. A wealth of trial data has proven them to be highly effective at lowering a person's heart attack risk.
In a paper published in the American Journal of Cardiology, Dr Darrel Francis and colleagues calculate that the reduction in cardiovascular risk offered by a statin is enough to offset the increase in heart attack risk from eating a cheeseburger and a milkshake.
Dr Francis, from the National Heart and Lung Institute at Imperial College London, who is the senior author of the study, said: "Statins don't cut out all of the unhealthy effects of burgers and fries. It's better to avoid fatty food altogether. But we've worked out that in terms of your likelihood of having a heart attack, taking a statin can reduce your risk to more or less the same degree as a fast food meal increases it."
One statin, simvastatin, is already available in low doses (10mg) over the counter at pharmacies without a prescription. Other statins are so far only prescribed by doctors, and limited by cost to patients at particular risk of heart attack or stroke. However, the cost of the tablets has fallen sharply in recent years (from ~£40/month to ~£1.50/month), such that the cost to the NHS of seeing a doctor is much greater than the cost of the tablet.
"It's ironic that people are free to take as many unhealthy condiments in fast food outlets as they like, but statins, which are beneficial to heart health, have to be prescribed," Dr Francis said.
Statins have among the best safety profiles of any medication. A very small proportion of regular statin users experience significant side effects, with problems in the liver and kidneys reported in between 1 in 1,000 and 1 in 10,000 people.
"Everybody knows that fast food is bad for you, but people continue to eat it because it tastes good. We're genetically programmed to prefer high-calorie foods, and sadly fast food chains will continue to sell unhealthy foods because it earns them a living.
"It makes sense to make risk-reducing supplements available just as easily as the unhealthy condiments that are provided free of charge. It would cost less than 5p per customer -- not much different to a sachet of ketchup.
"When people engage in risky behaviours like driving or smoking, they're encouraged to take measures that minimise their risk, like wearing a seatbelt or choosing cigarettes with filters. Taking a statin is a rational way of lowering some of the risks of eating a fatty meal."
Studies have shown a clear link between total fat intake and blood cholesterol, which is strongly linked to heart disease. Recent evidence suggests that trans fats, which are found in high levels in fast food, are the component of the Western diet that is most dangerous in terms of heart disease risk.
Dr Francis and his colleagues used data from a previous large cohort study to quantify how a person's heart attack risk increases with their daily intake of total fat and trans fat. He compared this with the decrease in risk from various statins, based on a meta-analysis of seven randomised controlled trials.
The results showed that most statin regimes are able to compensate for the relative risk increase from eating a cheeseburger and a small milkshake.
The researchers note that studies should be conducted to assess the potential risks of allowing people to take statins freely, without medical supervision. They suggest that a warning on the packet should emphasise that no tablet can substitute for a healthy diet, and advise people to consult their doctor for more advice.

Reflections: For those who like to eat fast food, this would be good news for them! Fast food Restaurants are giving out free Statin to reduce the risk of heart diseases like heart attack. What is Statin? Statin is a type of medicine that reduces the amount of unhealthy "LDL" cholesterol in the blood. A wealth of trial data has proven them to be highly effective at lowering a person's heart attack risk. Those who like to eat fast food would be over the moon and eat more from now on. However, in my opinion, eating fast food that increases cholesterol is still unhealthy and bad for us even though now we are given Statin. Statin only reduces the risk of getting heart diseases, but it does not eliminate the possibility of getting heart diseases. Anyway, there are always other vices for this, for example: fast food is too salty, less vitamin C, so on and so forth. Therefore, in a nutshell, I think that we should still eat less fast food as it still harms our body.

Culture Matters in Suicidal Behavior Patterns and Prevention, Psychologist Says:

Article from www.sciencedaily.com:"Everywhere, suicidal behavior is culturally scripted," said Silvia S. Canetto, PhD, of Colorado State University. "Women and men adopt the self-destructive behaviors that are expected of them within their cultures."
While the gender paradox of suicidal behavior is common, particularly in industrialized countries, it is not universal, she said. In China, for example, women die of suicide at higher rates than men. In Finland and Ireland, men and women engage in nonfatal suicidal behavior at similar rates. There are more exceptions to the gender paradox of suicidal behavior when one examines female/male patterns of suicidality by age or culture, she said.
In some cultures, particularly in industrialized countries, such as the United States and Canada, suicide is considered a masculine act and an "unnatural" behavior for women, Canetto said at a symposium entitled "New Perspectives on Suicide Theory, Research and Prevention."
"In these countries, the dominant view is that `successful, completed' suicide is the masculine way to do suicide. In the U.S., women who kill themselves are considered more deviant than men. By contrast, in other cultures, killing oneself is considered feminine behavior (and is more common in women)," she said, citing, among others, the Aguaruna people of Peru, who view suicide as an indication of a feminine inability to control strong emotions. Yet in other cultures, men's and women's suicidal behavior is similar. For example, in Sri Lanka, the same types of issues (problems with spouses, parents or in-laws) are typically associated with both women's and men's suicides.
"A broad cultural perspective shows that women and men do not consistently differ in terms of the kinds of suicidal behavior they engage in, or with regard to the circumstances or the motives of their suicidal behavior," she said. "When women and men differ with regard to some dimensions of suicidal behavior, the meaning and salience of these differences vary from one social group to another, one culture to another, one historical period to another, depending on local scripts of gender and suicidal behavior." The cultural variability in patterns and scripts of women's and men's suicidal behavior calls for "culturally situated suicidality research and prevention," Canetto said.
At the same symposium, James L. Werth Jr., PhD, of Radford University, discussed reasons why the suicide rate in rural America is consistently higher than it is in urban areas. In addition to general suicide risk factors, such as mental illness, a family history of suicide and feelings of hopelessness, rural residents may be more isolated, be less willing to ask for help and have increased access to lethal means such as guns and pesticides, he said.
"County by county or state by state, the top areas in terms of suicide are rural," Werth said. "The top five states are Alaska, Montana, New Mexico, Wyoming and Nevada, whereas D.C., New Jersey, New York Connecticut and Massachusetts have the lowest rates."
Some of the possible contributing factors to the higher rates in rural America are more poverty, higher unemployment and lack of access to treatment resources, Werth said. "People are not going to drive five hours to visit a counselor," he said.
In suggesting possible solutions to the rural suicide rate, Werth said greater access to broadband would help by increasing access to resources, as will integration of mental health practitioners into primary care.
"Even though people live farther apart, there may be stronger connections -- they need to rely on one another," he said. "There may be longstanding relationships among families and more religiosity …. we need to build on those existing qualities and strengths and beliefs."

Reflections: I was astounded by this article as I found out that in most countries, women suicide rates are higher than men are! Researches said that this depended on one’s cultural beliefs. In America, suicide was being seen as a masculine act and an "unnatural" behavior for women. However, in other countries, their culture believes that suicide is a feminine behavior. An example is the Aguaruna people of Peru, who viewed suicides as an indication of a feminine inability to control strong emotions. However, in my point of view, people who suicides are those who are under great pressures and stress or faced extreme sadness. I believed this as in Singapore, there are often many news about students of secondary or high schools that faced pressure and jumped down a building. In conclusion, I think that those who suicide are too stupid as they did not know how to cherish their life, which is very precious.

Periodic Table

The periodic table is being defined as a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns. Yet, we have to know much more than that! :(

Not only do we need to have the sufficient understandings about the periodic table, for example, what vertical and horizontal rows and columns are for, we also need to memorise what each rows represent, although, the middle portion we only need to know that it is called the transition metals. Alas! We still needed to know many other things. The properties of each and every group of elements for instance, and some usages of the different element groups.

To me, though periodic table is somehow, or quite significantly related to the previous topic of chemical bonding and atomic structure, I found it relatively difficult to memorise. I knew that this was because I did not see the link of it with the everyday lives of us. However hard it was to memorise everything, it was still an inevitable part that we needed to memorise. As such, I still prepared some notes to facilitate a more effective way of learning...

To see the notes, please go to my website. To view the notes directly, please go to https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzY2llbmNlZXBvcnR8Z3g6Mjc2YzhkMTQyYmNjMzFlNA

Have fun viewing!

Chemical bonding and atomic structure

Chemistry! Chemistry! Chemistry!

For my level at least, chemistry requires one to deposit a lot of effort, especially for the memorising part. Chemical bonding and atomic structure is the same. We needed to know how to draw diagrams and define the meaning of terms. Unlike biology though, in chemistry, I still find some interesting portions in which I was quite enthralled by. For instance, the bonding of molecules resulting in intricate molecular structure - those were quite fascinating.

This topic was also interesting because we could relate some of the things we learnt to our daily lives, especially how molecules bond in different states, thus resulting to different melting or boiling points. Prior to the introduction of this topic, I never did inquire why water, when below 0 degree celsius, would turn into a hard and cold solid. I only treated it as how nature works, and I never asked what the reasons behind these freezing and evaporating processes work.

Though molecules are some very tiny things (?) that we cannot see with our naked eye, through theory, we still understood quite some facts about them. At the same time, I was also very intrigued by how scientists discovered these many informations about the different molecular structures. I found out that though currently, chemistry only involves memorising work, they are still as interesting as any other topics. But they are only interesting when one really put in the effort to memorise them, understand them, and try to see them as a whole and the linkage between the topics and our daily lives. While we are learning more and more with each passing day, I rightly believe that our mind would slowly develop to be more inquisitive, while, noticing that the world of science is actually bigger than we expect.

To see my notes and effort put in for this term's test, please click on the hyperlink to see the webpage. To see my notes directly, please click on the following: https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzY2llbmNlZXBvcnR8Z3g6MmQ4N2Y1MzQzYmI2OGI5Yg

Happy reading!

Reflection: Term 1 test results

The topics tested in this term are namely periodic table, atomic structure and chemical bonding. I found that in order to score well in this exam of chemistry, the most important thing is to work hard and do a lot of memorizing work. As such, I compiled the notes that Dr. Tan gave to be able to revise more systematically and efficiently, and at the same time, setting aside some time for researching online for the uses of different properties of elements.

I find compiling notes very effective, since during the making of notes, my mind also absorbed the information, thus killing two birds with one stone. Furthermore, when compiling notes, I was also able to review what Dr. Tan taught in lesson and have a through “checkup” on how much I understood about the topics; in other words, looking through each and every part of the topics to see if I still did not have a grasp about any topic, or unsure and feared any topic. As such, I was able to have an overall understanding of how these topics relate to each other. I felt that this was more important than just stuffing all the facts into our mind without any “digestion”.

With weeks and weeks of revision, the test finally came, and went. The result was that I got barely touched A1 – 31.5/40. To be frank, I am not very pleased with my own results. Careless mistakes, loads of them in the test paper. This was partly because of the lack of time, or also could be due to my inaccurate time planning, therefore, resulting in being unable to check my answers. As a matter of fact, it is only carelessness that resulted in my decrease in marks, since I totally understood how to do those questions. It was perhaps out of pure rashness and lack of time which made me failed to properly comprehend the question before answering them. As a result, the effort I invested, I felt, was far more than what I should have gotten for my results. However, perhaps it was because I did not do enough practices, since I only memorized the facts and information. Hence, I resolved that I should not only memorise, but also do numerous practices for the next test, and hope that I could pass with flying colours.