Q&A - PSLE Science

[elkniwt]

Dear Robertpattinsonidle,


:thankyou:
And I really like your learning attitude. All the best for your PSLE!!! I am sure you will do well!!!

Robertpattinsonidle:

Alarmchain:

Thank you.

I think it is great that you kids are helping one another prepare for your exams. Very unselfish and magnanimous behaviour. You all should nominate each other for the EAGLES Award!

Cheers!

thanks. two brains is always better than one. here, everyone learns, so it is good to share your knowledge. by the way, any psle students or their parents here? i am a psle student too so please give me some advice!! :thankyou:

[elkniwt]

Dear Alarmchain,


Thank you for taking time to reply. And I fully agree with your views on the ambiguity and the differences in requirements in the a lot of science questions.

This question arises as it was put together with other actions :
- Winding up a toy car
- Clapping of hands
- Using a hammer to hit a nail
All the above requires the child to start with Chemical potential energy of the body, hence so arises the confusion for \"Switching on the ceiling fan\". My dd's query is - should we consider in terms of the action of turning the switch of the fan on (which starts with Chemical potential energy) or the electrical aspects of the electrical current and the fan spinning (which starts with Electrical energy) or put the two together.

It is tough for the 12-year-olds.

Alarmchain:

Hi elkniwt,

This is yet another excellent example of an ambiquous question.

Especially for this topic of energy conversion, my DD often gets confused as to what degree of details is expected? In this instance, is it Chemical Potential Energy of Body = KE of finger + KE of switch + Sound Energy? Or is it as pointed out by Charsen?

I would think it is the latter, but in expecting the children to be detailed and specific with their answers, I have often seen questions which are NOT specific and detailed to begin with .... sigh .....

In my effort to help my DD maintain her interest and, more importantly, her confidence in her reasoning skills, I will listen to her logic behind her explanation and if it makes sense, I will reassure her to ignore the marks and explain why I think her answer is right or wrong.

No choice, would rather lose this battle than the war for knowledge.

Cheers!

[charsen]

elkniwt:

Dear Alarmchain,


Thank you for taking time to reply. And I fully agree with your views on the ambiguity and the differences in requirements in the a lot of science questions.

This question arises as it was put together with other actions :
- Winding up a toy car
- Clapping of hands
- Using a hammer to hit a nail
All the above requires the child to start with Chemical potential energy of the body, hence so arises the confusion for \"Switching on the ceiling fan\". My dd's query is - should we consider in terms of the action of turning the switch of the fan on (which starts with Chemical potential energy) or the electrical aspects of the electrical current and the fan spinning (which starts with Electrical energy) or put the two together.

It is tough for the 12-year-olds.

Alarmchain:

Hi elkniwt,

This is yet another excellent example of an ambiquous question.

Especially for this topic of energy conversion, my DD often gets confused as to what degree of details is expected? In this instance, is it Chemical Potential Energy of Body = KE of finger + KE of switch + Sound Energy? Or is it as pointed out by Charsen?

I would think it is the latter, but in expecting the children to be detailed and specific with their answers, I have often seen questions which are NOT specific and detailed to begin with .... sigh .....

In my effort to help my DD maintain her interest and, more importantly, her confidence in her reasoning skills, I will listen to her logic behind her explanation and if it makes sense, I will reassure her to ignore the marks and explain why I think her answer is right or wrong.

No choice, would rather lose this battle than the war for knowledge.

Cheers!

Hi
You shuold consider the electrical apects of the electric current.There is nothing to do with the chemical potential energy of turning on the fan as you are just clicking the switch down,which is effortless.I suggest that your DD should not be confused by this.By turning on the switch,you are just closing the circuit.Clicking down the switch does not need so much of chemical potential energy,although we still need chemical potential energy to click down the the switch,the amount of energy used is negligable.
Cheers

[Michaelia0816]

Charsen,

I have some MCQ questions on impact of environment which I do not know how to do, so pls help me.

Links:
1) http://t.co/Jw9vFI2h
2) http://t.co/mYZ33kK5
3) http://t.co/zL2Arm7b
4) http://t.co/kEdTigE2
5) http://t.co/ZGiIIVKL

[Michaelia0816]

Can somebody help me with the questions?

[charsen]

Michaelia0816:

Charsen,

I have some MCQ questions on impact of environment which I do not know how to do, so pls help me.

Links:
1) http://t.co/Jw9vFI2h
2) http://t.co/mYZ33kK5
3) http://t.co/zL2Arm7b
4) http://t.co/kEdTigE2
5) http://t.co/ZGiIIVKL

Hi
So sorry for the late reply
Q1.For this question,I suggest that you count the no. of tolerant animals to the pollution to the animals sensitive to the pollution.If you do that ,you would observe that stream A has the most no.of sensitive organisms.Thus,Stream A is the least polluted.

Q2.For this question,you should see the wind direction and where factory T is.
Therefore,location C is definetly one of the answer and Location B cannot be the answer as the location is behind Factory T and the wind is blowing towards the location c direction.Thus,A and C should be the answer.

Q3.If you see the graph,notice that there is a increasing trend and a decreasing trend.Look at the part where the amount of dissolved oxygen decreased-(between pointC and PointD).I am going to give a explanation about the sewage.Sewage has materials which could be decomposed by the decomposers,in this case,bacteria.Bacteria is a living thing,thus,it needs oxygen to carry out its life processes.When Sewage is emptied into the river, bacteria is introduced into the river,in large amounts.The other aquatic living things would compete for dissolved oxygen with the bacteria since there is a large amount of bacteria in the water.Thus,pointC should be the answer.

Q4.I am not sure about this question and in my point of view,the answer is (2).A should be the answer as the water is pumped into the trenches,which has rocks to reduce the rate of evaporation.Option B does not have any relationship with the trenches.Therefore,the answer could be A and C.

Q5.Answer is (3).Option D cannot be the answer as global warming is not related to acid rain.Option C should be the answer as global warming contributes to the increase of atmospheric temperature.Thus,animals adapted to cold teperature would most likely die.Option A and B is the answer as it shows the changes of weather patterns due to the global warming which are correct.

When encountering man and the impact on his environment,ask yourself is the activity a positive impact on the environment or vice-versa.Think of the consequencesmof the activity and relate to the question.In that way,you would not be lost in these type of question.First,i suggest that you understand on this topic,using your textbooks.They will provide sufficient information on the topic.Revise with the Science PSLE revision guide and with the Science Booster Upper block.
Cheers

[Michaelia0816]

That alright, I would not mind, as it is a week holiday

[Michaelia0816]

Charsen, I do not understand questions as I think my brain turned rusty. I also did not have time to buy books, cause I have 13 homework left to hand in by the end of the weeks.


Links:
1) http://t.co/80XIx7NV
2) http://t.co/YzCxmd9c
3) http://t.co/TUmSiDm0
4) http://t.co/mVgtaBaQ
5) http://t.co/B0RRbXPV
6) http://t.co/adbRRQOq

Pls know that link 3 and link 4 is from the same question. Link 3 have a missing option, which can be found on top of link 4's question.

Appeciated if you can reply fast

[charsen]

Michaelia0816:

Charsen, I do not understand questions as I think my brain turned rusty. I also did not have time to buy books, cause I have 13 homework left to hand in by the end of the weeks.


Links:
1) http://t.co/80XIx7NV
2) http://t.co/YzCxmd9c
3) http://t.co/TUmSiDm0
4) http://t.co/mVgtaBaQ
5) http://t.co/B0RRbXPV
6) http://t.co/adbRRQOq

Pls know that link 3 and link 4 is from the same question. Link 3 have a missing option, which can be found on top of link 4's question.

Appeciated if you can reply fast

Hi
I see that you have many science homework to do.I am going to give a clue for each question.If you can find the answer using the clue,good for you.If not,reply and i will explain in detail.
Q1.This is a simple one.the clue is that the word north should appear towards the side of the north of the magnet.Thus,answer is (4)

Q2.Look at the circuit tester with the points labeled.That shows that this is the connection to light up the bulb.With that solve the question.Hint,B and F would it light up?Think.

Q3.You know that the ball has gravitational potential energy when it is about to be dropped.Do you think after you drop the ball,the gravitational potential energy would be converted to chemical potential energy?What energy would it convert to?

Q4.The answer is (4).You could only measure the height of the metal disc bounced to with the ruler.That is the DEPENDENT variable.You could only use the dependent variable or the independent variable to estimate the level of energy.

Q5.The clue is Up and Down.With this,You can find where they started.It is up and down,up and down.Using this Clue,you can visualize the trend of the graph.

Q6.Answer is (3).This is using maths,Units and parts.Assuming that the amount of chemical potential energy in each nutA and nutC has 9u and 3u respectively.9 nuts c have 27 units of chemical potential energy.3 nut A have 27 units too.This shows that amount of chemical potential energy in 9 nut c is equal to in three nut a.

Take a break and do your homework when your mind is free and fresh.And do not be overwhelmed by the questions in the homework.Take time to read the questions.
Cheers

[Michaelia0816]

Thx for your advice, I would think the link 2 carefully, cause it is the part that I most do not understand.