PSLE 2012 - Science
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nebbermind, do u find the info from the guides a little contradicting each other???
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The precise answer is :
a) whether there is any friction or not depends on whether there is any force applied on the object or not and the direction that it is applied. If on the slope, a force is applied such that there is a component of the same magnitude that is opposite and equal to the vector force due to gravitational force, the frictional force will be zero as well.
b) likewise if there is any force applied such that a net horizontal resultant vector force exist on the object on the horizontal surface, there is friction (whether it moves or not).
I dont think all these are spelt out clearly in the question. The setter did not specify the forces applied and he could also not specify because even if he did, in order to comprehend the full implication, the student need to know how to vectorise the forces and newton’s 1st and 3rd law.
This is an extreme case of a setter who is trying to test for "intuition" but does not have sufficient knowledge to set the context properly.
In my opinion, it is an "illegal" question and we should challenge it with MOE. -
verykiasumummy:
sorry ya... it is 23 sci guides.... oh my god.... :yikes: :yikes: :yikes:[/quote]Wow ksmummy, how to get 22 sci guides in the first plc? Wun u forget n buy 2 of the same?kwcllf:
[quote=\"verykiasumummy\"]i'm not proud to say that i have at least 10 sci guides at home... let me look thru all of them and give u all my conclusion since i have the resources available...
No wonder you call yourself \"verykiasumummy\"
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AWSP:
The question seems to be so over debated on the answer. Will be eager to see how the answer look like in the next year psle 5yr series. I guess till then that we will all know the answer ba.The precise answer is :
a) whether there is any friction or not depends on whether there is any force applied on the object or not and the direction that it is applied. If on the slope, a force is applied such that there is a component of the same magnitude that is opposite and equal to the vector force due to gravitational force, the frictional force will be zero as well.
b) likewise if there is any force applied such that a net horizontal resultant vector force exist on the object on the horizontal surface, there is friction (whether it moves or not).
I dont think all these are spelt out clearly in the question. The setter did not specify the forces applied and he could also not specify because even if he did, in order to comprehend the full implication, the student need to know how to vectorise the forces and newton's 1st and 3rd law.
This is an extreme case of a setter who is trying to test for \"intuition\" but does not have sufficient knowledge to set the context properly.
In my opinion, it is an \"illegal\" question and we should challenge it with MOE. -
AWSP:
Beg to differ. If there is no mention of any external force in the question or the diagram, it just means there is no such external force acting on the object. The only force that is assumed in such cases is that due to gravity.The precise answer is :
a) whether there is any friction or not depends on whether there is any force applied on the object or not and the direction that it is applied. If on the slope, a force is applied such that there is a component of the same magnitude that is opposite and equal to the vector force due to gravitational force, the frictional force will be zero as well.
b) likewise if there is any force applied such that a net horizontal resultant vector force exist on the object on the horizontal surface, there is friction (whether it moves or not).
I dont think all these are spelt out clearly in the question. The setter did not specify the forces applied and he could also not specify because even if he did, in order to comprehend the full implication, the student need to know how to vectorise the forces and newton's 1st and 3rd law.
This is an extreme case of a setter who is trying to test for \"intuition\" but does not have sufficient knowledge to set the context properly.
In my opinion, it is an \"illegal\" question and we should challenge it with MOE.
While P6 students donot need to know about components of force.and stuff, it should be common sense that to move an object down a slope is easier than that required to move it on a horizontal surface. And that is because of gravity aiding it. And that gravity does not help in moving an object horizontally. What I mean by that- if I want to push an object horizontally then I could push (exert a force) horizontally, or even at an acute angle. But if I were to push it down no matter how hard, still it would not move at all.
Friction is said to be the force that opposes motion. This is taught in the syllabus.
IMHO, children a keen interest for physical sciences are likely to conclude this. There are children who think about why when they play be it down the slide ( the higher the inclination, faster they slide, the longer the slide the greater the speed they hit the ground ) , with tops, ball games, carroms , science is aplenty. Being able to associate that with what you have read is what makes scientific thinking.
Again, IMO,
Is this a toughie , yes sure. Probably one of the differentiating Qs
Is it wrongly set , no I think, it is brilliantly set. -
Sun_2010:
Beg to differ. If there is no mention of any external force in the question or the diagram, it just means there is no such external force acting on the object. The only force that is assumed in such cases is that due to gravity.AWSP:
The precise answer is :
a) whether there is any friction or not depends on whether there is any force applied on the object or not and the direction that it is applied. If on the slope, a force is applied such that there is a component of the same magnitude that is opposite and equal to the vector force due to gravitational force, the frictional force will be zero as well.
b) likewise if there is any force applied such that a net horizontal resultant vector force exist on the object on the horizontal surface, there is friction (whether it moves or not).
I dont think all these are spelt out clearly in the question. The setter did not specify the forces applied and he could also not specify because even if he did, in order to comprehend the full implication, the student need to know how to vectorise the forces and newton's 1st and 3rd law.
This is an extreme case of a setter who is trying to test for \"intuition\" but does not have sufficient knowledge to set the context properly.
In my opinion, it is an \"illegal\" question and we should challenge it with MOE.
While P6 students donot need to know about components of force.and stuff, it should be common sense that to move an object down a slope is easier than that required to move it on a horizontal surface. And that is because of gravity aiding it. And that gravity does not help in moving an object horizontally. What I mean by that- if I want to push an object horizontally then I could push (exert a force) horizontally, or even at an acute angle. But if I were to push it down no matter how hard, still it would not move at all.
Friction is said to be the force that opposes motion. This is taught in the syllabus.
IMHO, children a keen interest for physical sciences are likely to conclude this. There are children who think about why when they play be it down the slide ( the higher the inclination, faster they slide, the longer the slide the greater the speed they hit the ground ) , with tops, ball games, carroms , science is aplenty. Being able to associate that with what you have read is what makes scientific thinking.
Again, IMO,
Is this a toughie , yes sure. Probably one of the differentiating Qs
Is it wrongly set , no I think, it is brilliantly set.
Oh mine the answer seems long. My DS would just give a short and sweet answer to it as usual. hmm..like that how to score?!? -
Sun_2010:
Sorry, I beg to differ. The solution is actually from my 2 dc. She has advance training in Physics and knows newtonian mechanics and vectorisation. She pointed out to me the question context is only on whether the object is stationary or not. I agree with her that the question depends on the presence and direction of the force which was not clearly specified and that all the question says is that the object is stationary.
Beg to differ. If there is no mention of any external force in the question or the diagram, it just means there is no such external force acting on the object. The only force that is assumed in such cases is that due to gravity.AWSP:
The precise answer is :
a) whether there is any friction or not depends on whether there is any force applied on the object or not and the direction that it is applied. If on the slope, a force is applied such that there is a component of the same magnitude that is opposite and equal to the vector force due to gravitational force, the frictional force will be zero as well.
b) likewise if there is any force applied such that a net horizontal resultant vector force exist on the object on the horizontal surface, there is friction (whether it moves or not).
I dont think all these are spelt out clearly in the question. The setter did not specify the forces applied and he could also not specify because even if he did, in order to comprehend the full implication, the student need to know how to vectorise the forces and newton's 1st and 3rd law.
This is an extreme case of a setter who is trying to test for \"intuition\" but does not have sufficient knowledge to set the context properly.
In my opinion, it is an \"illegal\" question and we should challenge it with MOE.
While P6 students donot need to know about components of force.and stuff, it should be common sense that to move an object down a slope is easier than that required to move it on a horizontal surface. And that is because of gravity aiding it. And that gravity does not help in moving an object horizontally. What I mean by that- if I want to push an object horizontally then I could push (exert a force) horizontally, or even at an acute angle. But if I were to push it down no matter how hard, still it would not move at all.
Friction is said to be the force that opposes motion. This is taught in the syllabus.
IMHO, children a keen interest for physical sciences are likely to conclude this. There are children who think about why when they play be it down the slide ( the higher the inclination, faster they slide, the longer the slide the greater the speed they hit the ground ) , with tops, ball games, carroms , science is aplenty. Being able to associate that with what you have read is what makes scientific thinking.
Again, IMO,
Is this a toughie , yes sure. Probably one of the differentiating Qs
Is it wrongly set , no I think, it is brilliantly set.
I think there should be other kids who are advance in science training who may have been penalised by such a question and perhaps think out of the box. (being kiasuparents)
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I agree with AWSP. If any assumptions are made, they should be stated in their question. If we are really trying to teach our children the correct "scientific method", then all the conditions under which a scientific experiment is carried out should be stated, and not assumed.
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AWSP:
Sorry, I beg to differ. The solution is actually from my 2 dc. She has advance training in Physics and knows newtonian mechanics and vectorisation. She pointed out to me the question context is only on whether the object is stationary or not. I agree with her that the question depends on the presence and direction of the force which was not clearly specified and that all the question says is that the object is stationary.
Beg to differ. If there is no mention of any external force in the question or the diagram, it just means there is no such external force acting on the object. The only force that is assumed in such cases is that due to gravity.Sun_2010:
[quote=\"AWSP\"]The precise answer is :
a) whether there is any friction or not depends on whether there is any force applied on the object or not and the direction that it is applied. If on the slope, a force is applied such that there is a component of the same magnitude that is opposite and equal to the vector force due to gravitational force, the frictional force will be zero as well.
b) likewise if there is any force applied such that a net horizontal resultant vector force exist on the object on the horizontal surface, there is friction (whether it moves or not).
I dont think all these are spelt out clearly in the question. The setter did not specify the forces applied and he could also not specify because even if he did, in order to comprehend the full implication, the student need to know how to vectorise the forces and newton's 1st and 3rd law.
This is an extreme case of a setter who is trying to test for \"intuition\" but does not have sufficient knowledge to set the context properly.
In my opinion, it is an \"illegal\" question and we should challenge it with MOE.
While P6 students donot need to know about components of force.and stuff, it should be common sense that to move an object down a slope is easier than that required to move it on a horizontal surface. And that is because of gravity aiding it. And that gravity does not help in moving an object horizontally. What I mean by that- if I want to push an object horizontally then I could push (exert a force) horizontally, or even at an acute angle. But if I were to push it down no matter how hard, still it would not move at all.
Friction is said to be the force that opposes motion. This is taught in the syllabus.
IMHO, children a keen interest for physical sciences are likely to conclude this. There are children who think about why when they play be it down the slide ( the higher the inclination, faster they slide, the longer the slide the greater the speed they hit the ground ) , with tops, ball games, carroms , science is aplenty. Being able to associate that with what you have read is what makes scientific thinking.
Again, IMO,
Is this a toughie , yes sure. Probably one of the differentiating Qs
Is it wrongly set , no I think, it is brilliantly set.
I think there should be other kids who are advance in science training who may have been penalised by such a question and perhaps think out of the box. (being kiasuparents) :)[/quote]Nice having this conversation, makes me think.
Just my opinion,
In a way I agree , primary school science needs to be taken with a big pinch of common sense. Actual calculations using complex scientific formula and pure scientific jargon etc is not needed. But an understanding of the basic principle is a must. So some basic assumptions is perfectly ok.
For instance , handles for pans are made of Bakelite , wood etc - the traditional insulators. My daughter when she was in p3 was shocked and could not believe that some pans in my kitchen have metal handles that do not become hot. Technology has advanced a lot, even rubber can be made with great variations in its properties. But we explain from the basic properties of the materials. I remember science work time with DD was filled with so much arguments, how that is not the way psle science answers , how her teacher knows and I don't - that things are different now, sometimes even telling that her teacher doesn't know ... :roll:
It's good to know more , but try not reading too much into simple applications. Some GEPpers I know face this problem. When the grasp of advanced knowledge strong, it should come with the skill to scale back, to understand when assumptions are ok. It comes back to the point of understanding what is it the question is trying to test. -
Laura02:
I agree with AWSP. If any assumptions are made, they should be stated in their question. If we are really trying to teach our children the correct \"scientific method\", then all the conditions under which a scientific experiment is carried out should be stated, and not assumed.
If a diagram shows an object is at rest and no indication of force acting on it, that means no external forces are acting on it.
And unless it is stated to be on any other planet or space, we can safely assume that gravity is acting on it and it is acting downwards.
I dunno if it is just me, but to be these assumptions are pretty basic. Maybe be I :siao:
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