Friday, July 29, 2011

Sci Lesson 29/7


Today, we went through our online worksheets 4 and 5. It is about refraction of light and the application of refraction of light, like periscope etc. Our teacher started on refraction as the test topics were already covered, and thus we proceed on to refraction, before lenses next week.
Today, we basically just recap what we have learnt about refraction last lab lesson. I find this lesson useful, even though we have learnt about refraction last lab lesson. This is because the lab lesson mostly tested our accuracy when doing the experiment. However, today we get to apply what we have learnt into application questions and even drawing the rays. The worksheets have shown us really good examples of how question may ask us about refraction. However, as practice makes perfect, it would definitely be better if we could seek for more questions, and the more we practise, the better we are at application questions. At the end of the class, I'm glad that the teacher gave us 1 more worksheet on reflection so as to prepare us for the test !

Monday, July 25, 2011

Sci Lesson 25/7

Today, we went through the practical that we did last lesson. As I had spent my time last lesson clarifying my doubts, I paid double attention to today's lesson as we go through the practical. However, as I had already done my online lessons worksheets, the practical today was actually just a recap of what I had learnt. Below are a few things that I had learnt and recap today:

When light travels from a less dense medium to a more dense medium, the ray of light is refracted towards the normal. However, when light travels from a denser medium to a less dense medium, the ray of light is refracted away from the normal.

The angles of incidence, refraction are both zero when a light ray enters perpendicularly to a medium with parallel surfaces.

Conditions for incident ray to be parallel to emergent ray:
The surface which the light ray enters is parallel to the surface which the light ray exits and
the light ray enters and exits from the same pair of media.

The critical angle is when the angle of refraction in the optically less dense medium is 90 degrees, and the angle of incidence in the optically denser medium is the critical angle.

Total internal reflection occurs when the angle of incidence is greater that the critical angle and the incident ray is in the optically denser medium.

Today's lesson was more of a recap for me, and I find it efficient too, as I could learnt and remind myself some of the facts. It was truly a lesson in the right time, as the test is just next week, and a lesson for me to recap is very important.

Friday, July 22, 2011

Sci Lesson 22/7

Today, we went to the lab lesson to carry out our experiment on refraction. However, I had decided to use this time to clear my doubts instead, since all the necessary equipment is already present in the lab. Thus, I spent the whole of today's lesson clearing my doubts and it was a really nice feeling when I finally understand some of the concepts.
I had asked the teacher for an example of critical angle, how to realise when is it total internal reflection and not refraction, and also the reflective index. All these doubts were present when I was actually doing the online lesson worksheet, and today I had finally find this suitable time to ask.
My friends also cleared some of their doubt, and I was dumbfounded by the questions they asked too, such as the drawing of light rays if there were two objects together etc. I had also learned from their questions too. I find today's lesson very enriching, in the sense that I had cleared my doubts. Although I did not really do the practical worksheets for this lesson, I'm sure I could finish them at home after I had clarify my doubts.

Monday, July 18, 2011

Sci Lesson 18/7

Today, we went through the online worksheet 3 and abit of Refraction. The science online worksheet 3 is actually a very good paper for us to revise, as it comprises alot of questions that requires drawing, which I am weak in. I am weak particularly in understanding the question, and knowing where to draw the rays. Thus, after going through the worksheets and seeing the diagram, i finally cleared some of my doubts.
Before this lesson, I left most of the drawing questions blank as I have no idea what were the questions asking for. During the lesson, I follow along the teacher and got roughly what the question was asking for. However, today's lesson was not able to clear all my doubts as I am very bad in multi-tasking. Therefore, I suggest the teacher letting us copy the drawings before explaining rather than letting us copy while she explain, which is very confusing and we might missed out some of the important points. Nonetheless, I am glad for today's lesson as I managed to grasp what were expected and a few common mistakes while drawing before we move on. However, there is still some doubt that I had no time to clarify, such as when do we know if we were supposed to draw reflected or incident ray, and probably drawings on convex/concave mirrors instead. That's all for today, I have to go revise now, or if there's time, i would clarify with the teacher tomorrow.

Friday, July 15, 2011

Sci Lesson 15/7

Today, we went through some online lesson worksheets and also practical worksheets. Even though today was just going through of worksheets, nonetheless, I have learnt and gained some new knowledge. Today was the day I finally cleared my doubt of how to draw reflected rays on a concave and convex mirror. Originally, I thought the tangent was for nothing and the normal is to be drawn according to another tangent parallel to my paper. However, if this were to happen, it would be no difference from the plane mirror !!! (I learnt it today, haha)
I also learnt what to do if the question was phrased in that particular way. I learnt this in the online lessons worksheet, where i do not understand the worksheet's questions. However, after going through, I learnt what to do and could apply this in future questions.
Today's lesson was pretty straightforward, just going through of worksheets. However, this type of lesson is necessary, especially near the exams, so as to get us into the "exam mood".

Monday, July 11, 2011

Sci Lesson 11/7


Today, we went to the laboratory for our practical lessons. We were currently learning reflection of light and I was wondering, like what kind of experiment exactly are we using today. I went into the laboratory, with lots of questions and curiosity.
However, indeed, there's this transmeter ( I'm not sure how to spell) that actually contains a lightbulb and could show us the reflected rays with a mirror ! It was very cool and innovative. I was very engaged in today's lesson because I find the experiment and the equipment really nice and cool.
Today, I took away a few learning points too. I realised that one has to be extremely careful and precise when it comes to topics that involves measurement and angles. I made this mistake when I took makings on the wrong line, and my line ended up crooked. I also learned more about the reflection from a concave and convex mirror. In the previous lesson, our teacher just told us answers to the questions, but I realised I understand more visually, when i actually experiment with the concave and convex mirror in the laboratory. Overall, this lesson was really fun and fruitful !!

Friday, July 1, 2011

Sci Lesson 1/7

Today, we were given all our online lessons worksheets at once. We were also taught how to draw an object's ray into the person's eyes and some "fast and efficient" methods. Today's lesson was very fun and engaging at the last, as our class made jokes while we draw the diagram. I really hope this kind of light mood would carry on forever, as it can help us to forget all our assignments and burden.
As always, the teacher's instruction was clear and straight. After looking at the online worksheets and resources provided, I think that the link provided was very useful. This would help us to complete the assignment and learnt from it rather that unable to complete a difficult worksheet and learning nothing out of it.
After second lesson on "reflection", i find this topic rather easy to grasp, just a ruler and a pencil and we could draw rays and surface etc.