Science Exemption please....

EOY is approaching soon, less than a month away. And with our school's exemption policy, I do sincerely hope that I could get a Science exemption so that I could focus on my other weaker subjects. To study this year's Science syllabus is really quite time-consuming I think, and I am really scared I am short of time.Even though I had gotten A1 for all 3 terms, I know my average is still below the cohort average, the basis on which exemption would be given. Hopefully I can make it... I really put in great deals of effort for Science this year, and I missed exemption last year with a mere 1 mark below average. That was sad. And thus I am especially determined to get exemption this year. However, I am glad that my average did improve this year, from 79 to 81. I have also been consistently updating my e-portfolio here, knowing that it was one of the criterion for exemption. At the same time, it has also helped me to get myself more aware of extra Science knowledge, and at the same time recap my older ones. Nonetheless, I am still going to work hard on revising my Science for an imminent, expected EOY, maybe one or two days in a week,regardless I have exemption or not. The main focus right now should be on the Biology topic of sexual reproduction which will the final topic to be covered next term. I think by putting in enough effort I should be able to maintain my current A1 grade. Maybe that would give me an extra option if I could enter SMTP.But right now, I can only hope for a miracle...... Though this year's Science journey is rather arduous, it will still be enjoyable!

Switching from Coal to Natural Gas Would Do Little for Global Climate, Study Indicates

Report Link: http://www.sciencedaily.com/releases/2011/09/110908124505.htm

Again, a very serious and concerned big issue today: Global Warming.  In short, this topic can be summed up in a phrase: Everything is always a double-edged sword;nothing in the world is perfect. Coal, deemed as the cause of global warming, can actually also help to alleviate the problem by blocking incoming sunlight with its released particles ,though to a small extent. A better alternative, natural gas, actually turns out to be releasing methane gas, another common greenhouse gas that traps heat in the atmosphere. This is indeed a headache. This can really become a huge problem, as these two are still our major energy source. If more cleaner alternatives do not come out, with the current status quo, our problem of global warming may in fact be accelerated. A sustainable and viable alternative would be nuclear energy, as we all know. It is harnessed from the fission of nucleons in atoms which releases large amounts of nuclear energy. No greenhouse gases is also emitted in the process, and it has virtually no side-effects on the environment. Besides, unlike coal and natural gases, it is also renewable. However, if carelessly discharged into the air, its radioactivity can kill and cause cancers. Nuclear disasters like the recent Fukushima nuclear disaster, Chernobyl and Three Mile Island, all highlight the dangers of nuclear energy. This has already deterred some countries like Germany from tapping on nuclear energy widely in the future. The development of nuclear energy has somehow come to a standstill . We cannot continue like this, or our earth will perish soon enough. However, we can be said to be stuck in a deadlock. I think the only  solution to this would be to continue exploiting other alternatives of energy such as solar and wind energy etc, though insignificant and expensive they may be. They can still help to alleviate the problem more or less. Who knows one day they will be more developed and widely used across the world?  At the same time, it would be still up to man to protect his own environment to combat against global warming. Who knows, this article may just be hinting that we are doomed.....
                                      

Science ACE Term 3

Again my Science ACE for Term 3. This time round, I decided to do this ACE assignment with my friend Rixin, at the same time as our recap and extension for our Biology topic on ecology this term.We were rather unclear about this topic besides revising from the Biology textbook for the test, so we decided to sort out some confusions with this. But this time round we only got 4 ACE. I think this was because maybe our contents were just covering the key ideas of these bioegeochemical cycles without going in depth. Nonetheless, I would like to share it for your information:In this presentation, you will learn how the content we learnt for biology this term can be applied to our surrounding environment and how they are related. You should also get a better understanding on ecology then. Happy learning! :
http://www.mediafire.com/file/vy2s2hvieghdmxz/science%20ace%20term%203.pptx

Term 3 and test reflections

Not too bad, but not that good. Just 33 or 83/100. This time the test paper was really rather easy, compared to the previous one. Still could not get higher. But overall I am quite satisfied, though I had still expected higher. Old kind :One or two pure mistakes and one or two careless ones. I can't comment quite much on this term's performance. Again, I had to try and correct my problem of carelessness. Think that would pretty well solve these problems. Nonetheless, this term's performance is definitely something to be glad about, keep up and even improve on.  This term's topic on lenses and ecology s rather manageable too, just that the latter is much more content-based and may need some memorisation. However, both of these do have very close relation to our surroundings and are thus very informative topics to learn about. In a nutshell, the focus on Science should continue to be maintained, and everything will be fine.

Diverging lenses

We were taught that there are basically two types of lenses, namely converging and diverging lenses(concave lenses/negative lenses). My impression was that diverging lenses was the one that was oddly-looking. But we will only be taught the principles of converging lenses this time. As you know, I always like to learn out of the box. So I just want to seek out some differences between the two types of lenses. So as mentioned, diverging lenses are thicker at their edges and thinner at the middle, totally contrary to converging lenses. The 3 principle rays forming an image from a diverging lens also looks just opposite to those of converging lenses, and as they are rather hard to define here, I have placed their images here. Just like the converging lenses, the point at which all the 3 rays converge would be the image point, just that they are being traced back. However, they are simply imaginary rays drawn backwards of the lens to find the point. The true refracted rays of the lens never meets. Thus, a virtual image is formed behind the lenses, as the it will appear as though light were coming from the image point. It is therefore conclusive that all images seen through a diverging lens will appear upright, diminished and virtual. I think this can better help me remember the properties of the converging lenses too, so its quite worthwhile.

Blueprint for this topic(Lenses):
-Remember the six different types of principle images formed by converging lenses and their properties

-Remember the 3 principle rays of a converging lens image

All about light.....

After a month's break, it was always tiring to come back to school. Heard that we would continue learning light , and that would be about optics and lenses. The topic was indeed rather stale for us, giving that we had been doing it last term. Nonetheless, I just went online, read my textbooks and glanced through some basic content we would most probably covering to give me a better understanding.  I basically understood most of the things, but I think except one. I came across the thin-lens equation in Gaussian form, which is the 1/u+1/v=1/f equation, and I had seen it before in some Physics reference books. Curious, I went to read more about it, and it literally gave me a headache with those sophisticated scientific terms that I had no single idea of. Hope we won't be learning something like that......

Science ACE Term 1( for Term 2)

This is my Science ACE for Term 1, but since there is no Science ACE for Term1, I am doing it for Term 2 in Term 1. I got 5 marks for this, so I think I would share my presentation here on the exceptions in covalent bonds , a topic taught in Term 1.

http://www.mediafire.com/?54traccupa7uj8w

Science Eureka sabbatical reflections

Yes, finally. I had been bidding for this sabbatical since last year, and it seems to be quite popular. I wanted to expand my Science knowledge, and hopefully the extra things learnt in this sabbatical can go a long way in my Science learning, not merely for tests. The period of five days was still rather short, but I still had deep impressions of my fun time in this sabbatical. I finally can get to expose to the use of more scientific apparatus and even conduct more experiments on myself. Most of our activities were experiments with occasionally some teachings in between by our Sec 4 seniors. The coverage of the course ranged from biology, chemistry and physics. Most of our activities were rather hands-on, and we learnt mostly from the results of the experiments itself. I just savour that kind of experience. This should be the purpose and process of learning Science! Some of us even mixed up the chemicals in the lab for fun, though it is dangerous to do so. But the very process of exploring Science is indeed irresistible. At the final day of the course , we were even given a mini-quiz on the things that we have learnt over the past few days, most of which consisted of acids in Chemistry. Not too bad, I got 18/20. We were also tasked to give a presentation in our groups on some Science topics that we are supposed to research on, and if I remembered correctly, I did something on bond energy and catalysts. I think I still got the powerpoint so I shall share it. There were also times of frustration during the course, for example, when we got the wrong results for our experiment or when we made a mess of it. I must say that you need some extent of patience and perseverance to go through them. Most importantly, I can get to experience the intuitive learning of Science. I truly felt that Science was not totally about memorisation and that there are different approaches of learning it. Experiments are indeed effective, as you can see the results for yourself, instead of just reading the contents on books. You could thus also remember them more vividly and easily. I think I would definitely join more of such meaningful, fruitful and enriching programs, and hope the school will organise more of them too.

Sabbatical PPT: http://www.mediafire.com/file/fb6uzooh7b23j5y/Presentation1.pptx

Thoughts on my Term 2 Test Performance

One word to express my feelings: Horrible. The score was really under my expectation. After the test and the tremendous effort I put in, I had expected myself to get at least the same score or even better than the last test. But it was dreadful that it turned out to be wrong. The test on light, acid and bases was not as easy as I had taught.I just managed to get onto the bottom line of A1, a 75.5. And out of my surprise, there were 2 perfect scorers in my class. This was the second lowest I got for my Science tests since Sec 1, and this was when I had actually done ample revision this time round.Certainly I had to reflect upon and analyse what exactly had gone wrong this time. Flipping through my test paper after receiving it, I seriously could not believe my eyes. The majority of the mistakes I made were actually out of carelessness.  To raise a few specific examples, it would be MCQ question 13. I actually misread angle of incidence as angle of refraction and got the question wrong. This was only one of the instances, and they costed me dearly. I think one of the factors behind this would be overconfidence. I think that I have been too overconfident over this test and also during the test itself. I thought that I could have gotten most of the questions correct.Maybe it had subliminally caused me to make these errors. Thus, I learnt a valuable lesson, that overconfidence can cause one's downfall, and that sufficient preparation does not always guarantee one success. Life is always so unpredictable. But never mind, I will encourage myself not to give up and continue to strive for greater heights next time. I would certainly be able to get over this pretty soon. GO ON!

Lab lesson on Light

This week, we were introduced to the new topic of light. As I am more inclined to Chemistry, the first time when I heard about this topic, I felt that it was pretty boring. I did not look forward to it in any way. This was also because I had a concept that light was an extremely complicated topic involving many theories and formulaes. But after today's lab lesson, I found that light was actually quite an intuitive topic. I think we have been taking light around us for granted without knowing its background theories. I am glad I learnt that today. We conducted experiments on the properties of light and how it would refract and reflect at different angles to an object or mirror. I am actually quite intrigued, especially when I saw the refraction of light. It was also rather cool, as we did the experiments in the dark.At the same time, our science teacher has taught us some basic information on light and mirror, such as the different types of mirror and the laws of reflection etc. After all these,I felt that I was truly en"lightened". After all , light wasn't so complicated at all. In fact, unlike other topics, I found out that light involves the least amount of memorisation. Know the basic principles, observe carefully and you will be able to handle questions on light. Physics was indeed a livelier subject. I now look forward to an enriching experience of learning a new Physics topic.

Salts and halides

We learnt that the neutralisation process of an acid and a base produces only salt and water. The definition of salt here are ionic compounds that result from neutralisation and are composed of a cation and anion, and is thus electrically neutral. The cation is usually a metal from the acid, while the anion is usually a non-metal base. There are different types of salts formed,  such as nitrite salts, base salts, acid salts etc. But the one specific one I am talking about today would be halides. Most salts are halides.The definition of halides would be a compound consisting of a halogen atom and another which is less electronegative than the halogen. The latter is usually a metal also. Examples of these would be sodium chloride, silver bromide etc. Like all salts, the cation is placed at the front of the chemical name. The halogen in this case is called the halide ions, which are negative. Thus these are usually called metal halides, which can be used in energy-efficient lamps. I came across this term in the powerpoint for revision and because it seemed interesting , I went to find out more on it. These has greatly improved my overall understanding on salts and I am glad that I learnt something more out of this.

Strength of acid and alkali

Today's Science lesson we covered about acids(produces H+ ions in water) and bases(produces OH- ions in water), and were given a worksheet to do.  There was a question about the meaning of strong and weak acids or alkalis. We were told to answer that strong acids or alkalis form more H+ or OH- ions when dissolved in water. However, I think that this answer is rather vague and seek for a definition or measurement of "strong". I found out that one way to determine this could be through  obtaining the enthalpy change of the substance. This is the amount of heat energy given out or taken in during a chemical reaction. When the acid or alkali molecules dissolve in water, they break up into different ions. A acid is usually made up of a non-metal(usually halides or halogens) and hydrogen ions, while an alkali is made up of a metal and hydroxide ions. For example, when hydrochloric acid dissolves in water, H+ and Cl- ions are formed. During this process, heat is needed to break the ionic bonds between the elements, and more heat would thus be used to break down the molecules completely into more H+ or OH- ions.Thus, it can be deduced that the greater the enthalpy change of an acid or alkali, the stronger it is. For example, the enthalpy change of a strong acid, hydrochloric acid is -74.84 kJ, while that of acetic acid is- 1.51kJ.  Ammonia, a weak alkali has a change of -30.50kJ, while potassium hydroxide's is -57.61kJ. The heat of reaction is either positive or negative, depending on whether it is exothermic or endothermic. I am glad that my own questioning has allowed me to learn out of the box, and I hope to continue doing so in future.


Blueprint for this topic:

Strong Acids= More H+ ions , Weak Acids= Less H+ ions
Strong Alkali=More OH- ions,  Strong Alkali=Less OH- ions
Acid+Metal=Salt+Hydrogen
Acid+Carbonate=Salt+Water+Carbon dioxide
Neutralisation: Acid+Base=Salt+Water
Base+Acid=Salt+Water
Base+Ammonium Salt=Salt+Ammonia+Water


Basic Information:

Thoughts on my Term 1 Test Performance.

To improve ourselves we must always review on ourself and what we have done. To do better for the upcoming next term, I would like to comment about my performance in this Term 1 Test 1. Scoring 34/40, or 85 marks, I am still behind many of my fellow classmates who scored around 35-38. In fact, around half of the class has passed this test with flying colors,and this indeed let me feel kind of left out and lagging. Anyway, it has been generally thought that this test was rather easy, and as long as you put in some effort, you will definitely soar high in this test. I think that the reason behind this score was that I had not put enough effort in my Science revision this term, largely due to the lack of time. I am rather weak in Maths, and had to spend more time on it as the test was on the day after the Science test. Thus I did not really had a comprehensive revision, and besides, I thought that I was rather relax on those few days before the tests. Luckily, I had prepared for my Science a few months ago., and have largely based on my memory and impression during the test.And that was when I did not memorise much content.Thus, I would say that my achievement this time round contained much of  the element of luck.Maybe I had to work on my management of my time. But looking at the score of my friends, I realized that importance of perseverance and diligence which would always prove worthwhile.Given the status quo I was in, I am really satisfied that I had obtained this result. However, I promise to strive harder for next term for greater heights and would do my best. Most importantly, out of all this test, I have realized what are the aspects I am weak in so as to allow me to upgrade myself, not the score of it.

Formation of Xenon Flouride

Regarding to the formation of compounds and bonds, I have discovered a interesting,additional fact and would like to share it here,which I also did it for my ACE too.The compound name xenon flouride certainly looks difficult but cool. Let us understand it then.As we know, xenon is an unreactive, stable noble gas,with the electronic configuration of 2.8.8, while flourine is a halogen with the configuration of 2.7. It is widely regarded that noble gases will not combine with other elements to form compounds. Why can this compound still form a covalent compound with the electronic configuration of XeF2(xenon flouride can still exist in many other forms). First of all, it would be due to the structure of the xenon atom. As xenon is located at the foot of its group, it has a large number of shells and are thus heavier than the lighter ones.Hence, the outermost electrons experience a shielding effect from the inner electrons that makes them more easily ionised, since they are less strongly attracted to the positively-charged nucleus. This results in an ionization energy low enough to form stable compounds with the most electronegative elements, fluorine and oxygen, and even with less electronegative elements such as nitrogen and carbon under certain circumstances. Ionisation energy is the force or energy needed for an atom to give up and remove its electrons. Electronegativity would then mean an atom's ability or tendency to attract electrons to itself to form a anion. Each element's has its own electronegativity represented by a value. It is classified that elements that have the electronegativity difference of 0.2-0.5 would form non-polar covalent bonds(where there is equal sharing of electrons), 0.5-1.6(polar covalent bonds,unequal sharing) and above which will belong to ionic bonds. Xenon's electronegativity is 2.60, while flourine's is 3.98. The difference would thus mean a non-polar covalent bond formed. For those who don't quite understand what I am discussing about, you can refer to the electronegativity table online. Nonetheless, after all this, you will find this extremely interesting.


                                      

Reflection on Term 1 Syllabus

After the end of Term 1 , I would like to reflect on my Science experiences this term. Basically ,we have been focusing on the study of the Periodic Table this term. As all of us know, the Periodic Table is also closely related to the study of electrons,atoms and properties of elements etc. Firstly, we would have to know the properties of an basic atom,what it contains etc.From the Periodic Table,we can deduce the proton and neutron numbers of an element and also its electronic configuration.  After knowing how to interpret the Periodic Table ,we will go into the more profound study of chemical bonds. In Sec 2,we are only introduced to two types of bonds formed between elements when they react, that is the ionic bonding and covalent bonding, formed dependently on the chemical properties of the elements,and thus we know the formation of compounds around us. I would like to say that the topic taught this term is extremely integral in our journey of learning Science as it lays the foundation of the study of chemical reactions in the coming years. By understanding this topic well, we will be able to predict easily what chemicals ,or reactants,we should combine to achieve a certain product. Through this topic,I am also be able to marvel at the infinite posibillities of Science as the different number of reactions between the 100 plus elements ranging from the common elements to the lanthanides, from the halogens to the alkali metals, are countless and unique. I also felt my interest in Science was piqued even more as this topic allows me to remove the qualms that I had last year about chemicals and elements. Last but not least, this topic is interactive and is thus interesting and easy to learn. For example, I found that I could easily remember the electronic configuration of elements easily without even memorising the periodic table like my friends. That makes it fun too.