Q&A - P3 Science

[usaik]

Hi Tianzhu,


Thank you so much for taking time to provide all the explanation. Looks like the answer key is not to be trusted fully.

MERRY XMAS & A HAPPY NEW YEAR TO YOU TOO!!!

[janet88]

In my opinion, it’s rather difficult to score high marks in Section B (open-ended questions)…just wondering how I can help son to improve.

He does well in MCQ but teachers are very particular with answers in open-ended.

There was a question on Maglev train in P4 SA2 paper. The students were asked to state 2 advantages of using magnets used in Maglev train. Hubby & I read the answer given by teacher and just couldn’t understand it.

[usaik]

Hi Janet_lee88,

My son did badly for the open-ended qns too. I am still figuring out how to help him too. For a start, I am trying to figure out the questions and answers for myself.

Can you share the answers given by the teacher for the Maglev train question?

[janet88]

usaik:

Hi Janet_lee88,

My son did badly for the open-ended qns too. I am still figuring out how to help him too. For a start, I am trying to figure out the questions and answers for myself.

Can you share the answers given by the teacher for the Maglev train question?

Q: What are the 2 advantages of using electromagnets over permanent magnets in the magnetic levitation train?

Teacher's answer: 1) We can control the strength of the magnet.
2) We can switch on and off the electricity when we want the train to stop or move.

[Tang]

usaik:

Hello....I need help to understand the concept and why the expected answer to the question for part (b) below.


This is how the question goes:
http://postimage.org/image/2673bkczo/

This is the given answer :
http://postimage.org/image/2jfzm7tc4/

With reference to part (b), the answer seems to be just repeating what the graph is showing instead of explaining why organ S has the most amount of food digested. Is this the expectation in an answer for all such questions? ** Please help ****

Hi,

The answer given for part (b) is correct as we are expected to make use of the graph to explain the reason.

If we mention more digestive juices and so more food digested, it will be marked wrong since the graph does not show digestive juices.

[tianzhu]

usaik:

Hi Tianzhu,


Thank you so much for taking time to provide all the explanation. Looks like the answer key is not to be trusted fully.

MERRY XMAS & A HAPPY NEW YEAR TO YOU TOO!!!!!

Hi

You're welcome.

I don’t think the WS’s answer is wrong in this particular instance.In answering this question, we still need to mention the higher proportion of digested food in organ S as shown in the graph.Just that we may feel that additional information is needed to ensure a more complete answer.

Organ S. The amount of digested food is the highest as compared to the other organs. More digested juices are added in the small intestine and digestion is completed in the small intestine.

Best wishes

[usaik]

Hi Tang, Tianzhu,

Thank you so much for your explanation. I do think Science is an interesting subject but the way the questions are set and the way they expect an answer sure need quite a lot of effort to get used to.

Hi Janet_lee88,
Thanks for sharing. I am pretty puzzled with the answer too. To me, there is no difference between point (1) and (2). We can control the strength of the magnet by the amount of electricity also imply that we can turn on and off the electricity of magnetic strength. :? Hope any experienced parent here can help to explain more on why the expected answer is as such.

[tianzhu]

usaik:

To me, there is no difference between point (1) and (2). We can control the strength of the magnet by the amount of electricity also imply that we can turn on and off the electricity of magnetic strength.

Hi usaik

There is a difference between point 1 and 2.

1) We can control the strength of the magnet.
2) We can switch on and off the electricity when we want the train to stop or move.

In primary science, students learned that we can make a magnet by using electrical method

The magnetism can be made stronger (using the example of winding a piece of wire around an iron nail)
- increasing the number of turns of wires around the iron nail
- increasing the number of batteries used.

Applying this concept, you can increase the strength with increase in number of batteries or number of turns in wire. I think you can see removing the batteries as equivalent to turning off the electricity.

Best wishes

[Tang]

usaik:

Hi Tang, Tianzhu,

Thank you so much for your explanation. I do think Science is an interesting subject but the way the questions are set and the way they expect an answer sure need quite a lot of effort to get used to.

Hi Janet_lee88,
Thanks for sharing. I am pretty puzzled with the answer too. To me, there is no difference between point (1) and (2). We can control the strength of the magnet by the amount of electricity also imply that we can turn on and off the electricity of magnetic strength. :? Hope any experienced parent here can help to explain more on why the expected answer is as such.

Hi,

For (1) - Depending on the weight of the trains, the strength of electromagnets may be adjusted so that we get the necessary and correct repulsive force to lift the trains.

For (2) - It is on or off, i.e. there is a repulsive force or no repulsive force. It has nothing to do with the strength of electromagnets.



With regard to the digestion question, my personal experience is that there is a danger that by giving extra information may result in zero mark because the marker may interprete that the pupil is regurgitating from memory instead of answering the question based on information given in the question.

[usaik]

Hi Tianzhu,

Thanks for explaining the difference between the 2. Good explanation indeed. I think the concept which you have used is certainly something which a P3/4 kiddo can understand.

Hi Tang,
Thanks for helping me to see the difference between the 2. I didn't realize how the train works until your explanation. :oops:

Thanks for the note of caution about the extra information. Hmm....I now think it is an ART to answer SCIENCE questions.