Reflections-term+3

This is the reflections page for term 1. This will also be where I will include all the components that I have mentioned earlier on in the 'Home' page. Enjoy reading!

__**Teaching and learning issues**__
In term 3, we learnt about separation methods. There are many types of separation methods. Some of them are filtration, evaporation to dryness, distillation, magnetic attraction and paper chromatography. Firstly, I will talk about filtration. Filtration is the most straightforward method of separating a mixture of an insoluble solid from a liquid or solution. We do not use food sieves as a filter in the lab because filter paper contains many small pores invisible to the naked eye while not food sieves. The pores allow liquid/ solution to pass through while big particles are trapped. Below is an image of filtration. Now, I shall talk about evaporation to dryness. It is a possible method for obtaining the solute from a solution. When a solution is heated, the solvent evaporates, leaving behind the dissolved solids as residue. For example, to obtain crystals of salt from a salt solution, the solution can be heated until all the water evaporates. This method is used to separate dissolved solids from a solution. When a solution containing dissolved solutes is heated, the solvent will evaporate. Only the solute(residue) will remain in the evaporating dish. Next, I will be talking about crystallisation. Crystallisation separates a dissolved solid from a solution as well-formed crystals. Solubility of solutes decreases as temperature decreases. As hot solution cools, it becomes saturated. Extra solutes that cannot be dissolved separates as pure crystals. An example of crystallisation is silicon wafer. Next, I will be talking about chromatography. Chromatography is a method of separating and identifying the components in mixtures. There are three methods of chromatography. They are High Performance Liquid Chromatography, Gas Chromatography and Paper Chromatography. Basically, chromatography separates mixtures based on the solubility of the different solutes in the mixture in as solvent. Paper Chromatography is used to separate small amounts of mixtures. It is used to identify components of a mixture or to test the purity of a liquid. The solvent chosen for use in chromatography must dissolve the dyes present. As the solvent travel up the paper, it bring along with it all the dyes. Now, I will talk about distillation. Distillation is used to separate a pure liquid from a solid-liquid or liquid-liquid mixture. There are 2 processes involved in distillation and they are boiling and then followed by condensation. Also, there are two types of distillation. They are simple distillation and fractional distillation. Firstly, I shall talk about simple distillation. It is a process of obtaining a pure liquid from a solution. The solution is boiled until the liquid reaches its boiling point when it changes into gas. The vapour travels to the condenser to form the pure liquid which is collected as the distillate. For fractional distillation, it is used to separate two or more miscible liquids. Fractional distillation has a fractionating column that separates liquids in order of boiling points. The liquid with the lowest boiling point boils first and its vapours travels up the fractionating column, condenses in the condenser and is collected as distillate.

This term, my target is to get at least an A2 for my science test. My actual grade is an A2, which means that I have achieved my target. I got 70 marks for my test over 100. Last term, I achieved a B3, which was not up to my targets, and I inevitably broke down into tears when I got my results. I had expected at least an A2, but in the end, even though I did revise, I still failed to accomplish my goals. So, I decided to be even more hardworking. Thus, I revised my work after Mr. Lim taught us. Some good practices are that I revised my work, lessen the amount of time on less priority stuffs and even preventing myself from going online. Of course, there were still some careless mistakes that I could not afford not to lose. I did check for careless mistakes, but maybe I did not really go into details and skimmed through. Sometimes, I cannot even spot careless mistakes even when I go into details. I promise myself to go further into details in the future. I hope to achieve an A1 next term as it is the final ordeal a.k.a EOY! So, I must work harder than I am now so as to achieve my goals and not to disappoint those who care for me. I shall make sure that I know every thing that is important. All the best for me!
 * __Termly performance reflections__**

__**Hands-on experiences**__ This term, we did experiments based on what we learnt. One of the experiments was on paper chromatography. The aim is to find out the colours in different brands of black ink. The apparatus and materials are: boiling tube, retort stand, chromatography paper(15 cm x 2cm), split cork, black ink, ethanol and water mixture. Firstly, we mark an ink spot on one end of the chromatography paper. Next, we place the strip of chromatography paper between the two pieces of the split cork. Next, we fill the boiling tube with ethanol and water mixture to a depth of about 2cm. Next, we lower the strip of chromatography paper into the boiling tube and we must make sure that the ink spot is just above the liquid level in the tube. Lastly, we leave the set-up to stand. I observed that the solvent moves up the strip of chromatography paper, the ink dissolves in the solvent and is separated into different components. Experiment done!

The next experiment is also on separation techniques. The aim is to separate a mixture of salt and sand. The apparatus are: beakers, filter funnel, glass rod, evaporating dish, tripod stand, wire gauze, Bunsen Burner and retort stand. The materials are: mixture of salt and sand filter paper. Firstly, we place the mixture of salt and sand in a beaker. Add 10cm^3 of water into the beaker. Stir the contents in the beaker. Add more water to dissolve the salt if necessary. Now, we fold the filter paper into a cone. Next, we fit the folded paper into the filter funnel. Place an evaporating dish below the filter funnel. Pour the mixture from step 1 into the funnel. Next, we set up the apparatus with the beaker standing on the tripod stand heating, and placing the evaporating dish containing salt solution over the mouth of the beaker. This method is called evaporation to dryness. Overall, it was quite an interesting experiment as we got to know more about separation techniques by doing the experiment. It sounds like "learning by doing". Of course, there were many other experiments which were also fun, but I think that I prefer experiments that we can really understand the topic.