Today, I asked them a few questions to improve their conceptual understanding of electricity:
(1) What is the difference between e.m.f and potential difference?
(2) What is the difference between resistance and resistivity?
(3) How do you derive the unit for resistivity?
(4) Why does the resistance of a metallic conductor increase when its temperature increases?
(5) Why is the ammeter connected in series to a resistor but the voltmeter is connected in parallel?
Some points to note:
(1) Resistance is NOT the gradient of the V-I graph.
(2) The I-V and V-I graphs of a conductor may be different and you’ll need to understand why and explain the difference.
Rgds,
Ilyasa, M.Ed, PGDE, ex-MOE Math and Physics teacher (hp: 97860411)
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Sec 4 A. Math Reflections 02/02/13 – Higher Derivative
Today I taught them the Higher Derivatives, using displacement, velocity and acceleration as real-life examples. I chose not to introduce the 2nd derivative as a means to test whether a turning point is a maximum or minimum, as I preferred to do that when teaching the application of differentiation in tangents and normals at a point in a curve.
Points to note:
(1) students must not write the 2nd derivative as dy^2/dx^2;
(2) d^2y/dx^2 is not the same as (dy/dx)^2;
(3) d^2y/dx^2 is the same as f”(x) or f^2(x);
(4) there may be product rule, quotient rule or chain rule involved when finding the higher derivatives.
Rgds,
Ilyasa, M.Ed, PGDE, ex-MOE Math and Physics teacher (hp: 97860411)
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JC 2/1 H2/H1 A-Level Economics Tuition for 2013
For our latest timetable, click here => 
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ORIGINAL POST (OUTDATED):
(1) JC2 H2 Economics: (Investment amt: $320 per month)
Sat 7.00 pm to 9.00 pm
(2) JC2 H1 Economics: (Investment amt: $320 per month)
Sun 7.00 pm to 9.00 pm;
(3) JC1 H2 Economics: (Investment amt: $320 per month)
(upon request)
(4) JC1 H1 Economics: (Investment amt: $320 per month)
(upon request)
DETAILS:
Location: Blk 627 Bukit Batok Central #07-640
Tutor(s): Mr Jay Lim, Master of International Management, ex-banker, experienced full-time tutor.
Content: A-Level micro and macro economics, directed readings, case studies, examples from real life and current affairs.
Focus: How to score in economics essays, must-have skills for handling economics case studies, metacognition in economics, thinking the economists’ way.
Class Size: 2-6 students
To register, kindly call, or send an sms to 97860411, indicating the Student Name, Subject and Level.
Related links:
(1) Economics Revision Package
(2) General Paper Resource & Practice Package
Sec 4 Physics Reflections 27/01/13 – Applications of Electrostatics
I wanted to proceed to Current Electricity, but the students wanted more discussion on how to answer application questions on electrostatics.
So I supplied them with quite a number of such application questions, often with confusing diagrams. The key to answering such questions is to first draw the distribution of charges on the items in the diagram, and identify which objects are conductors and which are non-conductors. For the conductors, check whether they are insulated from the surroundings.
Key points to note:
(1) Only non-conductors can be charged by rubbing (why?)
(2) Electrons can flow into and out of only conductors, and only when the conductors are in contact with other conductors (why?)
(3) A charged object can attract a neutral conductor (why?) and a charged object can also attract a neutral non-conductor (why?)
(4) Upon contact with a highly charged object, a conductor behaves differently from a non-conductor (why?)
Rgds,
Ilyasa, M.Ed, PGDE, ex-MOE Math and Physics teacher (hp: 97860411)
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For our latest timetable, click here =>
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Sec 4 A. Math Reflections 26/01/13 – Quotient Rule
I introduced Quotient Rule to the class last week so today we continued with it. Quotient Rule is actually very easy to use and should not be replaced by the Product Rule, even though it’s very convenient for students to write a fraction as a product of two terms.
What students find difficult is in simplifying the resulting expression, which often consists of fractions within fractions, with some terms having a square root sign over it. Of course there is a ‘trick’ to get the factorisation done quickly and correctly, but it’s too cumbersome for me to demonstrate here. More importantly, this difficulty that students often face highlights the point that I’ve posted earlier, that Sec 1 and Sec 2 Algebra is VERY IMPORTANT.
For the next lesson, I’ll be going into the Second Derivative as well as Application of Differentiation to curves, tangents and normal. We may be covering the Chain Rule if we have time.
Rgds,
Ilyasa, M.Ed, PGDE, ex-MOE Math and Physics teacher (hp: 97860411)
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For our latest timetable, click here =>
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Sec 4 Physics Reflections sun1415 20/01/2013 – Electrostatics
I completed the teaching of Electrostatics to this class of 6 eager boys from a top school. First I showed a video of how a home-made electroscope is used to determine the kind of charge on a rubbed insulator.
I like to link topics to real life, so I described to them one of my roles while serving NS – to attach cargo to the bottom of a helicopter in what is commonly known as “underslung” operations. But we have to discharge the helicopter first, which is flying above our heads, using a long earth wire, else we may get an electric shock.
We covered definitions, procedures and concepts such as electric field and electric field lines. I even taught them an A-Level formula, F = Qq/kr^2, so that they understand that the electric force between two charged particles is the same for both charges even though the sizes of the charge on them are different.
We also discussed answers to a challenging worksheet and true enough, the students have certain misconceptions about charges and their movement.
Next week, we’ll start on Current Electricity. It’ll be fun.
Ilyasa, M.Ed, PGDE, ex-MOE teacher
(hp: 97860411)
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For our latest timetable, click here =>
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Sec 4 A. Math Reflections sat1415 19/01/2013 – Differentiation
This was our third lesson in Jan. We did the Product Rule for Differentiation after spending the last two sessions doing the Basic Rule and the Power Rule (a subset of the chain rule).
I told students to differentiate directly, in line, and not use the “let u = f(x) and v = g(x)” which is longer, more confusing and can cause more careless mistakes.
Now they are able to perform dy/dx = f(x)g'(x) + g(x)f'(x) quite quickly without introducing new variables such u and v which can be quite clumsy. Most of the time, finding dy/dx is part of a larger question, so it is unwise to make this part too long.
I ended the lesson with an intro to the Quotient Rule. Again, I don’t recommend the use of u’s and v’s and instead differentiate directly in line. We’ll be practising the Quotient Rule in the next session.
Again I tell students that Calculus is almost one-third of the A. Math syllabus, so if you want to get A1 you have to master Differentiation and Integration, which, in my opinion (and students hate it every time I say it), are amongst the easiest of topics in A.Math.
However, Integration at the A-Levels (H2 Math) can be quite difficult. But we’ll cross the bridge when we come to it. : )
Ilyasa, M.Ed, PGDE, ex-MOE teacher
(hp: 97860411)
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For our latest timetable, click here =>
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P6 (PSLE) Math & Science Tuition at Concept Learning
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EDUCATIONAL SERVICES:
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By EX-MOE TEACHERS & EXPERIENCED TUTORS
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For more details, kindly visit www.conceptlearning.sg, or call 97860411.
Effective JC H2 / H1 Economics Model Essays
On Monday, a Mrs Lee came to collect the GP Resource and Practice Package that she ordered. I didn’t realise she had come to my place before, until she mentioned that her daughter’s econs essay marks had improved significantly (from ard 5 to ard 19 marks now)after reading and studying the Economics Essay Revision Package that she had bought from me earlier. If you dont believe this, you can call Mrs Lee directly if she agrees to be ‘interviewed’. However, her daughter’s case study marks didn’t improve so I’m looking into it to understand why.
Well, I wasn’t surprised at all, as the same set of essays had been used by my Math student, Emily, to get an A at her Econs a year earlier (you can verify it with her if she agrees; she’s now studying in the US after getting four As in her H2 subjects). For those of you econs students who are too busy to attend econs tuition, and you can self-study, I would encourage you to purchase this Econs revision package that I had compiled. The essays may not be perfect (you may even add to them), but are far better than those written by average Econs students.
Alternatively, if you live near Bukti Batok, you can come to my place for econs tuition, which will be taught by Mr Jay Lim, an ex-banker in his 50’s, who has wide experience in practising finance and economics, and supported by myself and the materials that I have compiled. Although not an ex-JC teacher, Mr Lim is US-trained, and very comfortable with case studies and very familiar with the world of economics, finance, international trade and banking. He is also currently tutoring an IB student in Business & Management.
For enquiries, just give me a call or sms, to 97860411.
Rgds,
Ilyasa, M.Ed, PGDE, ex-sch teacher
Teaching Science to kids everyday…
Parents play a key role in getting children interested in Science. Science is a living subject that surrounds us everyday. There’s Science in the kitchen, the bathroom, the living room, in fact, everywhere. The following are some questions that children typically ask, or questions that parents can ask their children, so as to set their minds thinking:
(1) Why do metallic objects feel colder than wooden ones?
(2) Why does ice feel cold?
(3) Why is the air-con unit placed near the ceiling?
(4) Why do we feel cold just after taking a bath?
(5) Why does oil float on water?
(6) Why does ice float on water?
(7) Why do metal ships float on water?
(8) Why does the swimming pool appear shallower than it really is?
(9) How does a pair of spectacles work?
(10) How does a fan work?
(11) Why do we need to breathe air?
(12) Why do oranges and lemons taste sour?
(13) Why do salt and sugar melt faster in warmer water?
(14) What causes the tides in the sea?
(15) Why are we able to see the moon?
(16) Why do moving toys need batteries? What goes on in a dry cell?
(17) Why does food last longer when frozen?
(18) Can a see-saw be balanced when two people are sitting on it? How?
(19) Why does the swing stop after some time?
(20) ……………..
There are many more such questions that parents and children can think of. These questions have both vague, unscientific answers as well as the scientific ones. It is understandable that most parents have forgotten the correct answers to these questions, but this should not deter parents from learning with their children.
It would be a good idea for parents to buy or borrow a basic science encyclopedia to read with their children. Searching for information together on the internet is also a good joint activity between parents and children.
The true nature of Science is learning by thinking and exploring, observing and experimenting, making many errors along the way. It is this spirit of thinking and persistence that gives us many of the useful things that we have today, like electricity and aeroplanes. Teenagers can certainly afford to spend some time thinking about how computers or hand phones work, instead of just using them.
Ilyasa, M.Ed, PGDE, B.Sc, ex-sch teacher.