PSLE 2012 - Science

[AWSP]

MeKiasuLeh:

Science is too diversified a subject and MOE can only set a finite number of questions for students to complete in a fixed time frame. I also do not think MOE wanted to sieve the men from the boys so to speak but it will likely turn out this way if this forum is anything to go by.

Do we really have so much faith that there could be no error with MOE?
Have anyone ever wondered if there could be anything wrong with the PSLE T-score? A magic formula that no one knows but can only guessed at the working? Is it based on a normal distribution as it seems to be? What happens if the distribution is skewed to one side?
Is there some truth that we need to reduce the weightage in our second language as the previous minister of education attempted to do so because the students' standard is too low or is there another reason?
I have gone out of context.
Its time to take a closer look at the frog and tadpole question. How is the marking scheme for this question? Is the examiner expecting a unique correct answer and therefore would mark all else wrong? Or is he prepared to accept all answers that are not wrong? Are the teachers communicated as to the expectation of answering open ended questions if the decision is to accept all answers that is not wrong? Are the students prepped such that they can write all reasonable answers? If the setter has intended to only accept a singular unique answer to the question according to whatever concept he imagined to be right, has he erred in not ensuring that only a single unique answer can satisfactorily answer the question?
My 2 cents worth again

[atutor2001]

AWSP:

.... Is the examiner expecting a unique correct answer and therefore would mark all else wrong? Or is he prepared to accept all answers that are not wrong? Are the teachers communicated as to the expectation of answering open ended questions if the decision is to accept all answers that is not wrong? Are the students prepped such that they can write all reasonable answers? If the setter has intended to only accept a singular unique answer to the question according to whatever concept he imagined to be right, has he erred in not ensuring that only a single unique answer can satisfactorily answer the question?
My 2 cents worth again

I have quite good faith in the science marking scheme. They do not expect a unique answer but the main theme should be correct - for the frog question if I am not wrong, the focus should be \"survival of its kind.\"

So as long as students can support this theme with valid points, the answer should be acceptable. They will list the more \"usual points\" for markers' easy reference. If in doubt, markers can consult supervisor.

I believe the following points, together with any other valid points that can support the advantage of living in different habitats for young and adult will be acceptable :

a) do not compete from the same source of food
b) adults can survive when there is drought
c) less predators of young in shallow ponds
.....

[AWSP]

atutor2001:

I have quite good faith in the science marking scheme. They do not expect a unique answer but the main theme should be correct - for the frog question if I am not wrong, the focus should be \"survival of its kind.\"

So as long as students can support this theme with valid points, the answer should be acceptable. They will list the more \"usual points\" for markers' easy reference. If in doubt, markers can consult supervisor.

I believe the following points, together with any other valid points that can support the advantage of living in different habitats for young and adult will be acceptable :

a) do not compete from the same source of food
b) adults can survive when there is drought
c) less predators of young in shallow ponds
.....

Really? your list is already quite long, I can add some more
d) there are more food in the pond for the young.
e) tadpole can feed on vegetation and food in the pond when small while frogs can feed on insects and it can increase its chance in finding flies outside of the pond.
f) the skin of the tadpole needs to be kept wet wherease frogs are mobile enough to ensure its skin is wet.
I am sure with more ingenuity from students all around, the list can go on and on and we are all correct and not penalised?
But, what are we testing? There are numerous counter examples for frogs and tadpoles.
Why is it that adult fish give birth to its young in the pond and not on land? Why does the turtle lay eggs on the beach? Why is it that caterpillar and butterfly are both on land?
Is it just randomness of nature in the frog's evolution?
What if we put randonmness of nature in the frog's evolution - will that be right or wrong? Why should we mark it wrong?

[atutor2001]

AWSP:

....
But, what are we testing? ....Why does the turtle lay eggs on the beach? Why is it that caterpillar and butterfly are both on land?
Is it just randomness of nature in the frog's evolution?
What if we put randonmness of nature in the frog's evolution - will that be right or wrong? Why should we mark it wrong?

You have brought up a very valid point i.e. what is the purpose of this question. Hope the authority does follow this forum and take note of your point.

[AWSP]

I also refer to last year’s question on being lost in the forest with inedible plants and armed with a plastic bag and cloth etc. I remembered seeing the preferred (or is it the only) answer as tying the plastic bag on the leaf and the water vapour from the stomata that condenses on the plastic bag???

What if I put "collecting morning dew with my cloth". Will that be marked right or wrong?
What if I decide to cut the plant, either the root or stem and squeeze out the water content? Or maybe I am more creative, I put it in the plastic bag and collect the condensation? (assuming only inedible and not poisonous)
what if I decide to hunt for insects and worms? The question only mentioned about inedible plants and fruits.
What are the marker’s expectations?
What are the P6 science teachers’ expectations in answering these type of questions? Are the students prepped such that their mind will not go blank from overthinking about what PSLE science wants them to write?
Note : that the main thrust of my argument is the last para and not a debate on the answer:)

[mummy so kiasu]

atutor2001:

AWSP:

....
But, what are we testing? ....Why does the turtle lay eggs on the beach? Why is it that caterpillar and butterfly are both on land?
Is it just randomness of nature in the frog's evolution?
What if we put randonmness of nature in the frog's evolution - will that be right or wrong? Why should we mark it wrong?

You have brought up a very valid point i.e. what is the purpose of this question. Hope the authority does follow this forum and take note of your point.

Concern parents should write to MOE instead of just posting on this forum. Can they provide answer key to all the schools? I don't think the authority will follow on this forum.

[mummy so kiasu]

Nebbermind:

rains:

Aiya, so incidental that I happen to be the marker lor - that's how I know he's bluffing! Ya lor. Psle over one week already. What's there to discuss? Then you still come and discuss for what?

:rotflmao:
Good one there!

Your profile says you are the government & now you say you are the marker. :?

[mummy so kiasu]

rains:

Yapyap:

My bother, whose sc teacher saw the answers, says that she said the the answer to the frog/tadpole question is that the tadpoles don't compete with the frogs for food, and if predators eat the frog, they cannot eat the tadpoles.

Eh, you want to bluff also cannot bluff until like that lah. Psle marking hasn't started and the teacher got to see the answers ah? I think even principals also cannot see yet leh.

And tadpoles and frogs eat different types of food. How can competition for food be possible?

Tadpoles eat insects and frogs eat algae or plants ah?

I think it is a typing error. It should be the science teacher saw the question and not the answer.

[AWSP]

I have just gone through the previous postings on the friction question again. I saw a brilliant answer using static coefficient of friction to justify the existence of ‘potential friction’. This can only be from a student who read beyond the syllabus.

Can we justify penalising the exceptional students who have chosen the answers according to this concept?
I saw also arguments using "potential movement" to justify another answer. I have raised a counter example of a balancing force vector such that there will be no net force and therefore no friction but yet there is potential movement. If the concept is used to answer this question in physics, it would be marked clearly wrong. There is no such thing as potential movement.
Who do we penalise and who to reward?
I will also argue for those who are so affected that they cannot choose any answer and leave it blank. If you have been taught that friction exists during motion only, what would you have chosen? Would they be faulted or is it the P6’s teachers fault for not be able to bring across concepts of forces, equilibrium to a simple level so that the question can be tackled. And then again, doing so would require some degree of spotting the question?

[Nebbermind]

Also, I have mentioned that there is a possibility of a ‘frictionless surface’, ie, object is free to slide down without any frictional force.

I feel they should omit the question.