Saturday 15 September 2012
Science E-Portfolio
This E-Portfolio is done by Oh Jianyong from class 2I3. This is my Science E-Portfolio where I am supposed to reflect about what I have learnt in my first, second and third term in school and also share about independent works done by myself.
Summaries of important science concept
Term 1 (Chemistry)
This term, we focused on chemistry. The topics learnt included the periodic table, the atomic structure, acids and bases and writing chemical equations. For atomic structure, we learnt about the atomic model, isotopes. electronic configuration and valence shells. For the periodic table, we learnt about periods and groups, transition metals and chemical bonding. We also learn how to draw a dot and cross diagram of both ionic and covalent compounds. We also learnt about the properties of metals, non metals, giant ionic structures and simple molecular substances. For acids and bases, we learnt about the definition and uses of acids and bases. Also , we learnt how to balance chemical equations.
This term, we focused not only on physics but also salt preparation which is a chemistry topic. For physics, we learnt about reflection, refraction, total internal relection and prisms. We also learnt how to do ray diagram drawings and how to calculate the refractive index and critical angle of different transparent materials. Furthermore, we also learnt about how refraction and reflection can affect our lives. We learnt the properties of a plane mirror reflection and how refraction can affect our perception of the depth of water to make it look more shallower than it actually seems. For physics, a lot of emphasis was placed on calculation and application of the formulas we learnt in class to aid us in our explanation.
For salt preparation, We learnt about the different methods of salt preparation such as titration, precipitation and reaction of acids with insoluble substances method. One important thing I remember is that to get the hydrated crystals, we cannot evaporate to dryness but must instead heat the solution to saturation before cooling. Furthermore, it was a step by step procedure that included clear explanation for each step and it had to be memorised to at least a certain extent.
Term 3 (Biology and Lenses)
This term we focused on biology and lenses, which is a physics topic. For biology, we learnt about human and plant reproduction. We learnt about mitosis, meiosis, STDs, contraceptives, the menstrual cycle, pollination, double fertilization. Biology was full of the most content to memorize. For example, we have to memorize words like Luteinising hormone, Follicle Stimulating hormone, Grafiaan Follicle, Oestrogen and Progesterone. However, it may be easier in the sense that there are not as many concepts as in physics to apply so not so much thinking is involved but rather more memorisation is involved.
For lenses, we learnt about the properties of converging and diverging lenses. We learnt how each image would look depending on the object distance and the focal point of the lens. How to tell if the object is far away through parallel light rays and how the light rays will diverge/converge as it passes through the diverging/converging lens.
This term, we focused on chemistry. The topics learnt included the periodic table, the atomic structure, acids and bases and writing chemical equations. For atomic structure, we learnt about the atomic model, isotopes. electronic configuration and valence shells. For the periodic table, we learnt about periods and groups, transition metals and chemical bonding. We also learn how to draw a dot and cross diagram of both ionic and covalent compounds. We also learnt about the properties of metals, non metals, giant ionic structures and simple molecular substances. For acids and bases, we learnt about the definition and uses of acids and bases. Also , we learnt how to balance chemical equations.
It was interesting to know that these elements, though having vast differences in many different properties were able to be classified in the periodic table. I also did a research on the creation of the periodic table and I found it very interesting on how it was evolved from one man to another. More information will be on my independent researches post but because of the research I have new found respect for the men that created the periodic table.
Term 2 (Physics and Salt Preparation)This term, we focused not only on physics but also salt preparation which is a chemistry topic. For physics, we learnt about reflection, refraction, total internal relection and prisms. We also learnt how to do ray diagram drawings and how to calculate the refractive index and critical angle of different transparent materials. Furthermore, we also learnt about how refraction and reflection can affect our lives. We learnt the properties of a plane mirror reflection and how refraction can affect our perception of the depth of water to make it look more shallower than it actually seems. For physics, a lot of emphasis was placed on calculation and application of the formulas we learnt in class to aid us in our explanation.
For salt preparation, We learnt about the different methods of salt preparation such as titration, precipitation and reaction of acids with insoluble substances method. One important thing I remember is that to get the hydrated crystals, we cannot evaporate to dryness but must instead heat the solution to saturation before cooling. Furthermore, it was a step by step procedure that included clear explanation for each step and it had to be memorised to at least a certain extent.
Term 3 (Biology and Lenses)
This term we focused on biology and lenses, which is a physics topic. For biology, we learnt about human and plant reproduction. We learnt about mitosis, meiosis, STDs, contraceptives, the menstrual cycle, pollination, double fertilization. Biology was full of the most content to memorize. For example, we have to memorize words like Luteinising hormone, Follicle Stimulating hormone, Grafiaan Follicle, Oestrogen and Progesterone. However, it may be easier in the sense that there are not as many concepts as in physics to apply so not so much thinking is involved but rather more memorisation is involved.
For lenses, we learnt about the properties of converging and diverging lenses. We learnt how each image would look depending on the object distance and the focal point of the lens. How to tell if the object is far away through parallel light rays and how the light rays will diverge/converge as it passes through the diverging/converging lens.
Termly reflections
Term 1 Test Reflection
For this term test, I got a bare B4 which is to me a mark that leaves much to be desired. I believe that this term’s results is due to my badminton competition that, which due to unfortunate timings coincided with all my science lessons and caused me to miss the bulk of them. However, it is still no excuse for the poor results as there were adequate notes and exercises given out to at least help me get a B3 grade, if not better. Furthermore, I should have seeked help from my friends as many of them did much better than me and could have been more than useful to me.
Term 2 Test Reflection
For this term test, I once again got a B4, however this time I really have no excuses. Badminton competitions did not clash with science lessons and physics, I originally thought was easier than chemistry too. The main problem I think, was that I neglected the topic of salt preparation and in the end did not even perform as well as expected in the light questions. Furthermore, I did not do a complete enough revision and failed to do the critical analysis question due to time constraints because I lost concentration mid-way through the test. I would probably have done better if I had put in more effort to understanding and learning how to apply certain physics concepts in other areas.
Term 3 Test Reflection
For this term test, I got an A1, which was an unexpectedly good mark considering that I was mostly focussing on the human reproductive system when most questions that came out were for the plant reproductive system. I think that the cause of this is that the critical analysis question this time was a give away question. As such, I could easily get 5 marks more than usual while wasting less time. Thus, it is still too early for me to relax as it was out of sheer luck that I could get an A1, furthermore it was a bare A1 as well. If it were not for the bonus quiz, I do not even think that I could have gotten an A1 at all.
Term 4 Upcoming Exams
For the End of Years, I think that I should put a lot of focus on chemistry as I am not strong in that area and have already forgotten almost everything of the little that I know of the topic already. However, I do hope to be able to get an A1 as I have already done it before in term 3. Another thing I should take note of is my speed as last year, due to lack of time, my Section C pulled down my science grades.
For this term test, I got a bare B4 which is to me a mark that leaves much to be desired. I believe that this term’s results is due to my badminton competition that, which due to unfortunate timings coincided with all my science lessons and caused me to miss the bulk of them. However, it is still no excuse for the poor results as there were adequate notes and exercises given out to at least help me get a B3 grade, if not better. Furthermore, I should have seeked help from my friends as many of them did much better than me and could have been more than useful to me.
Term 2 Test Reflection
For this term test, I once again got a B4, however this time I really have no excuses. Badminton competitions did not clash with science lessons and physics, I originally thought was easier than chemistry too. The main problem I think, was that I neglected the topic of salt preparation and in the end did not even perform as well as expected in the light questions. Furthermore, I did not do a complete enough revision and failed to do the critical analysis question due to time constraints because I lost concentration mid-way through the test. I would probably have done better if I had put in more effort to understanding and learning how to apply certain physics concepts in other areas.
Term 3 Test Reflection
For this term test, I got an A1, which was an unexpectedly good mark considering that I was mostly focussing on the human reproductive system when most questions that came out were for the plant reproductive system. I think that the cause of this is that the critical analysis question this time was a give away question. As such, I could easily get 5 marks more than usual while wasting less time. Thus, it is still too early for me to relax as it was out of sheer luck that I could get an A1, furthermore it was a bare A1 as well. If it were not for the bonus quiz, I do not even think that I could have gotten an A1 at all.
Term 4 Upcoming Exams
For the End of Years, I think that I should put a lot of focus on chemistry as I am not strong in that area and have already forgotten almost everything of the little that I know of the topic already. However, I do hope to be able to get an A1 as I have already done it before in term 3. Another thing I should take note of is my speed as last year, due to lack of time, my Section C pulled down my science grades.
Excursion Reflections
Introduction
The place I went to for the field trip is the botanic gardens. There, I saw far far more trees than flowers, however, this time I am going to focus more on the flowers as I failed to observe anything on the trees that I could relate to a science concept.
Well to begin with, as I was observing a strange flower, I noticed a bee flying around and going to each of them and making a weird noise as it made contact with the flowers. I thought it strange at first but upon closer look I realized that it was actually the process of pollination. Every time the bee got near the flower, there was a “click” sound and I watched with interest until the bee left.
This got me thinking about the process of pollination and a few questions came into my mind. Firstly, we all learnt how bees pollinate flowers in primary school but what I want to know is why exactly they would want to help flowers reproduce. Secondly, I wanted to know whether the insects were attracted by the flowers or anything with nectar would do, including hands. Finally I wanted to know how many flowers reproduce by pollination and maybe know a few of the more common ones.
Why do bees pollinate flowers?
To begin with, the bees are not even aware that they are helping the plants in their process of pollination and reproduction. The bees were simply attracted to the nectar that was full of sugar and was the bees’ main source of energy. Also, they were attracted to the pollen which provided them with the fats. The pollen sticks onto the bees’ legs when they are on the flower and slides off the bees’ legs while the bee is on another flower and hence, pollination occurs. The bees collect nectar in order to take it back to their nest where worker bees turn it into honey. This honey is then placed into honeycombs and sealed with wax so it can be eaten later. This is what the bees stand to benefit from helping the plants pollinate.
Are the insects solely attracted to the flowers or anything with nectar can attract insects?
Well, I did this experiment by rubbing my hands in nectar and placing it close to a butterfly in the botanic gardens and it did work, the butterfly was resting comfortably on my finger. However, when I tried to take a picture the butterfly flew away. I did not try it on bees and wasps because I thought it was dangerous. Therefore, anything with nectar can attract insects.
How many flowers reproduce by pollination?
About 80% of the flowers in the world reproduce by pollination.
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| Proof that I was there |
Well to begin with, as I was observing a strange flower, I noticed a bee flying around and going to each of them and making a weird noise as it made contact with the flowers. I thought it strange at first but upon closer look I realized that it was actually the process of pollination. Every time the bee got near the flower, there was a “click” sound and I watched with interest until the bee left.
This got me thinking about the process of pollination and a few questions came into my mind. Firstly, we all learnt how bees pollinate flowers in primary school but what I want to know is why exactly they would want to help flowers reproduce. Secondly, I wanted to know whether the insects were attracted by the flowers or anything with nectar would do, including hands. Finally I wanted to know how many flowers reproduce by pollination and maybe know a few of the more common ones.
Why do bees pollinate flowers?
To begin with, the bees are not even aware that they are helping the plants in their process of pollination and reproduction. The bees were simply attracted to the nectar that was full of sugar and was the bees’ main source of energy. Also, they were attracted to the pollen which provided them with the fats. The pollen sticks onto the bees’ legs when they are on the flower and slides off the bees’ legs while the bee is on another flower and hence, pollination occurs. The bees collect nectar in order to take it back to their nest where worker bees turn it into honey. This honey is then placed into honeycombs and sealed with wax so it can be eaten later. This is what the bees stand to benefit from helping the plants pollinate.
Are the insects solely attracted to the flowers or anything with nectar can attract insects?
Well, I did this experiment by rubbing my hands in nectar and placing it close to a butterfly in the botanic gardens and it did work, the butterfly was resting comfortably on my finger. However, when I tried to take a picture the butterfly flew away. I did not try it on bees and wasps because I thought it was dangerous. Therefore, anything with nectar can attract insects.
How many flowers reproduce by pollination?
About 80% of the flowers in the world reproduce by pollination.
Friday 14 September 2012
Independent Research (How John Newlands tried to classify the elements)
How John Newlands tried to classify the elements
In the year 1865, John Newlands discovered the law of octaves and classified 56 elements into 11 groups on the basis of their physical properties. The law of octaves basically states that every eighth element showed similar physical and chemical properties when the elements are placed in the order of their increasing atomic masses. The law of octaves is also applied even to our current periodic table.
Newlands was the first to recognize this and he was also the first to assign atomic numbers to the elements. Unfortunately, his work was also not accepted by his peers.
This was most probably due to the more obvious flaws of his table of elements. For example, the first row assembles elements with similar chemical properties together, such as fluorine, chlorine, bromine and iodine, but it also includes elements with different chemical properties together such as cobalt, nickel, palladium, platinum and iridium. Not only that, his table failed to leave room for new elements that being discovered. These mistakes were probably due to the fact that he was so enthralled by his discovery; he made the mistake of trying to force the elements into this pattern.
Independent Research (How Johann Dobereiner tried to classify the elements)
How Johann Dobereiner tried to classify the elements
Johann Dobereiner tried to classify the elements for the first time in 1817.He took three elements with similar properties, banded them together and called them triads. Chlorine, bromine and Iodine, for example, are one of the triads that Johann Dobereiner formed. The problem with this method is that firstly, a large number of similar elements like iron manganese, nickel, cobalt, zinc and copper could not be grouped into triads. Secondly, it was possible that elements with dissimilarities could be grouped into triads. Thirdly, Dobereiner could only classify 3 triads successfully. Since he failed to arrange the known elements in the form of triads his attempt at classification was largely regarded as a failure by other chemists of the time.
Between 1829 and 1858, a number of scientists found that these types of chemical relationships extended beyond the triads. During this time fluorine was added to the halogen group. Oxygen, sulfur, selenium and tellurium were grouped into a family while nitrogen, phosphorus, arsenic, antimony, and bismuth were classified as another family.
Johann Dobereiner tried to classify the elements for the first time in 1817.He took three elements with similar properties, banded them together and called them triads. Chlorine, bromine and Iodine, for example, are one of the triads that Johann Dobereiner formed. The problem with this method is that firstly, a large number of similar elements like iron manganese, nickel, cobalt, zinc and copper could not be grouped into triads. Secondly, it was possible that elements with dissimilarities could be grouped into triads. Thirdly, Dobereiner could only classify 3 triads successfully. Since he failed to arrange the known elements in the form of triads his attempt at classification was largely regarded as a failure by other chemists of the time.
Between 1829 and 1858, a number of scientists found that these types of chemical relationships extended beyond the triads. During this time fluorine was added to the halogen group. Oxygen, sulfur, selenium and tellurium were grouped into a family while nitrogen, phosphorus, arsenic, antimony, and bismuth were classified as another family.
Independent Research (Different properties of Elements)
I did research on the properties of different elements.
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| Name: Sulfur Atomic Number: 16 Average Atomic Weight: 32 Uses: It is used for making gun powder, matches, and fireworks |
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| Name: Magnesium Atomic Number: 12 Average Atomic W Uses: Magnesium is both strong and light, thus making it useful for making automobile parts. It is usually alloyed with metals like aluminum though |
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| Name: Calcium Atomic Number: 20eight: 24 Average Atomic Weight: 40 Uses: Calcium is required for human and animal nutrition. Calcium compounds are used in making lime bricks, cement and others… |
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| Name: Potassium Atomic Number: 19 Average Atomic Weight: 39 Uses: Potassium is used in nearly all the fertilizers in the world as it is essential for plant growth |
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