Tutor Niedino: Pri Science Questions and Concepts

[Niedino]

Tang:

Hello,

Question - Where does the water on the outside from a cup of cold orange juice come from?

Answer - The water vapour from the surrounding air comes into contact with the cool outer surface of the cup and condenses into water droplets.

My Personal Comment - The given answer will be marked wrong because of regurgitation from memory. It is 'too broad'.

Correct answer should have been \"Water vapour from the surrounding air.\"

If there is a need for 'How', normally the question will include \"Explain.\" behind the origin question or it will be given as part (b) of the question.

Hi Tang,

No offense, although the answer looks regurgitated, it required the student to apply their understanding to the question. If you were to ask me, \"water vapour from the surrounding air\" will be marked wrong, as water vapour is a gas and not a liquid. The concept being tested is that of condensation.

Although the question did not ask for explanations, it is important to that the students understand what the question is asking for and provide a full answer.

Thanks[/b]

[atutor2001]

I think there is another problem with science paper, which is "inconsistency" in the expected answer.


If a question is "Where does paper come from?", I am sure the answer "Paper comes from trees" will suffice. There would be no need to explain how wood is made into paper. Probably the school could argue that the answer to "how" is not expected because it is not covered in the syllabus. Nevertheless, I still feel it is good for science question to be phrased in such a manner, consistent with normal English usage, so as to avoid ambiguity.

Problems with the questions usually happen only in school papers and I think PSLE questions are OK. However, because of students exposure to incomplete question and inconsistent expectancy in school, they end up not knowing the limit to the answers required in PSLE.

A typical example is as follows :

An experiment was conducted by pouring equal amount of water into 3 identical funnels containing equal amount of 3 different types of soil. The time taken for 20 cu cm to flow through was recorded. What is the aim of the experiment?

The possible answers that students may have come across are :

1. To find out the the time taken for 20 cu cm of water to flow through each type of soil.
2. To find out the effect of each type of soil on the time taken for 20 cu cm to flow through.
3. To find out how different types of soil will affect the time taken for 20 cu cm of water to flow through.
4. To find out the porosity of each type of soil.
5. To find out which soil is the most porous.
6. To find out which soil retains the most amount of water.
7. To find out which soil would take the longest/shortest time for 20 cu cm of water to flow through.
…

Our poor kids would be getting wrong / correct for their answers, depending on the school’s marking scheme. Anyone can help to explain which is the best answer and which answers are not acceptable and why. Thanks.

[starlight1968sg]

atutor2001:

Problems with the questions usually happen only in school papers and I think PSLE questions are OK.

I am unsure about this part. If kids can't do well in the school papers, can they do well in PSLE?

[atutor2001]

starlight1968sg:

atutor2001:

Problems with the questions usually happen only in school papers and I think PSLE questions are OK.

I am unsure about this part. If kids can't do well in the school papers, can they do well in PSLE?

\"PSLE questions are OK\" meaning their questions are not ambiguous but can be very tricky. Only kids who are good in English will do well as they can understand the \"limits\" and requirements set in the question - so they don't have to waste time putting in the unnecessary extras.

For others who are trying to match questions to answers from what they have learnt in the past, they would not appreciate the \"limits\" set in the questions and continue to try their luck by including whatever they can remember in their answer, not knowing that certain part of \"standard answers\" is no longer relevant because the \"conditions\" set in the question can completely change the required answer. PSLE usually has a few questions that are very tricky and getting to understand the \"limits\" or \"conditions\" is not easy, which is why getting A* for science is tough.

[Niedino]

atutor2001:

starlight1968sg:

[quote=\"atutor2001\"]Problems with the questions usually happen only in school papers and I think PSLE questions are OK.

I am unsure about this part. If kids can't do well in the school papers, can they do well in PSLE?

\"PSLE questions are OK\" meaning their questions are not ambiguous but can be very tricky. Only kids who are good in English will do well as they can understand the \"limits\" and requirements set in the question - so they don't have to waste time putting in the unnecessary extras.

For others who are trying to match questions to answers from what they have learnt in the past, they would not appreciate the \"limits\" set in the questions and continue to try their luck by including whatever they can remember in their answer, not knowing that certain part of \"standard answers\" is no longer relevant because the \"conditions\" set in the question can completely change the required answer. PSLE usually has a few questions that are very tricky and getting to understand the \"limits\" or \"conditions\" is not easy, which is why getting A* for science is tough.[/quote]Hi atutor,

With regards to your earlier post, I would like to provide the flipside of the coin. PSLE questions can be \"ambiguous\" at times, depending on the process skill tested. Every year, after the PSLE, there'll be questions in the papers

Secondly, to the \"inconsistency\" of school papers, I would like to highlight that school papers are set by teachers who are professionals. This are the same professionals who mark the PSLE. Of course, there are papers that are set very well and there are papers that are set inconsistently, and I'm not debating that. We have to understand that school examinations are set to \"prepare\" pupils for the PSLE and hence very often, the setters are trying to set questions that might appear in the PSLE.

I hope not to set a debate on this topic, and close this subject, as the thread is started to focus on helping parents with Science concepts and particularly misconceptions.

So here's another misconception.

Students are often confused between the Primary Science definition of \"Hardness\" and \"Strength\" when they learn about the diversity of materials. Do try and ask your children about whether an object is \"hard\" or \"strong\" when it can withstand scratches or when it can withstand a lot of mass without breaking. Students are also confused with the state of being \"inflexible\" and being \"hard\", due to the prior understandings with the English definitions.

Hope it helps

[Niedino]

atutor2001:

I think there is another problem with science paper, which is \"inconsistency\" in the expected answer.


If a question is \"Where does paper come from?\", I am sure the answer \"Paper comes from trees\" will suffice. There would be no need to explain how wood is made into paper. Probably the school could argue that the answer to \"how\" is not expected because it is not covered in the syllabus. Nevertheless, I still feel it is good for science question to be phrased in such a manner, consistent with normal English usage, so as to avoid ambiguity.

Problems with the questions usually happen only in school papers and I think PSLE questions are OK. However, because of students exposure to incomplete question and inconsistent expectancy in school, they end up not knowing the limit to the answers required in PSLE.

A typical example is as follows :

An experiment was conducted by pouring equal amount of water into 3 identical funnels containing equal amount of 3 different types of soil. The time taken for 20 cu cm to flow through was recorded. What is the aim of the experiment?

The possible answers that students may have come across are :

1. To find out the the time taken for 20 cu cm of water to flow through each type of soil.
2. To find out the effect of each type of soil on the time taken for 20 cu cm to flow through.
3. To find out how different types of soil will affect the time taken for 20 cu cm of water to flow through.
4. To find out the porosity of each type of soil.
5. To find out which soil is the most porous.
6. To find out which soil retains the most amount of water.
7. To find out which soil would take the longest/shortest time for 20 cu cm of water to flow through.
.....

Our poor kids would be getting wrong / correct for their answers, depending on the school's marking scheme. Anyone can help to explain which is the best answer and which answers are not acceptable and why. Thanks.

Hi atutor,

Based on my experience, most students will write 1 and 3, which should be correct, as they do not learn porosity at the primary school level. The questions aims to test the pupils on their ability to make conclusions using the information given to them. However, for the very bright ones, who answer 4, 5 and 6, the mark will still be awarded to them as they have answered beyond what is expected of them. As for answer 2, it is not quite right as we're not really testing the effect and as for answer 7, the answer neglects to mention the different types of soil, so its not and ideal answer.

Hope it helps

[atutor2001]

Hi Niedino


I understand and appreciate your points and we shall leave it as it is. Incidentally, PSLE questions may not be set by Primary school teachers - just guessing.

Till today, (my kids are now in their teens), but I still do not know the best answer for the question below. I used to tell my poor kids to \"spam\", by combining all the key words into a single answer. Most appreicate it, if you can share your view on the most suitable answer for this question.

Thanks in advance.
[quote]An experiment was conducted by pouring equal amount of water into 3 identical funnels containing equal amount of 3 different types of soil. The time taken for 20 cu cm to flow through was recorded. What is the aim of the experiment?

The possible answers are :

1. To find out the the time taken for 20 cu cm of water to flow through each type of soil.
2. To find out the effect of each type of soil on the time taken for 20 cu cm to flow through.
3. To find out how different types of soil will affect the time taken for 20 cu cm of water to flow through.
4. To find out the porosity of each type of soil.
5. To find out which soil is the most porous.
6. To find out which soil retains the most amount of water.
7. To find out which soil would take the longest/shortest time for 20 cu cm of water to flow through.
.....
[/quote]

[atutor2001]

Hi Niedino


Thank you for your answers. Please ignore my earlier posting, didn’t know that you have already replied while I was posting. Thanks again.

[starlight1968sg]

Hi,

I need some help in
http://www.orlesson.org/orp/09Sc/2009-Sc-CA2-Nanyang.pdf Q24

Is the model ans correct in particular option B?

MTIA.

[Niedino]

starlight1968sg:

Hi,

I need some help in
http://www.orlesson.org/orp/09Sc/2009-Sc-CA2-Nanyang.pdf Q24

Is the model ans correct in particular option B?

MTIA.

Hi,

The answer should be (3). Option B is correct, as I assume the same substance mentioned here is blood.