Q&A - PSLE Science

[Sunflower 2000]

Thank you very much, Charsen!

[Recia Lim]

This question comes from PSLE booklet (Year 2007-2011) pg 122 Q24.b

Other than using a cloth to wipe the plates, suggest one way to make the plates dry even faster.

[Recia Lim]

How do we answer a question like "How did repeating the experiment make the results more accurate?"

[isetan]

Recia Lim:

How do we answer a question like \"How did repeating the experiment make the results more accurate?\"

Repeating the experiment Is to ensure results achieved is more consistent without significant fluctuation or surprises.

[whitety]

isetan:

Recia Lim:

How do we answer a question like \"How did repeating the experiment make the results more accurate?\"

Repeating the experiment Is to ensure results achieved is more consistent without significant fluctuation or surprises.

i thought repeating the experiment makes the results more reliable, not accurate

[charsen]

whitety:

isetan:

[quote=\"Recia Lim\"]How do we answer a question like \"How did repeating the experiment make the results more accurate?\"

Repeating the experiment Is to ensure results achieved is more consistent without significant fluctuation or surprises.

i thought repeating the experiment makes the results more reliable, not accurate [/quote]Hi
The purpose of reapeating the experiment is to obtain a more reliable or accurate results
More Accurate is accepted.
Cheers

[Michaelia0816]

charsen:

Michaelia0816:

Hi Charsen,

Long time no see! I need you to help me on some questions,

links:
1) http://t.co/GCyF1kMR
2) http://t.co/eVFTscPX
3) http://t.co/g48XDpin
4) http://t.co/IiFwd6yg

Hi
I am not going to tell all the answers.Use the strategy that i taught you.Find the topic and the concept of the question.For the circuit question,trace the electricity path of each option.
For each question,you tell me the topic and the concept.Once i correct it,you could find the answer.
Cheers

I dun know how to do Q1, but my answer for Q2 is 3, answer for Q3 is 1, answer of Q4 is 3. Am I correct?

[charsen]

Michaelia0816:

charsen:

[quote=\"Michaelia0816\"]Hi Charsen,

Long time no see! I need you to help me on some questions,

links:
1) http://t.co/GCyF1kMR
2) http://t.co/eVFTscPX
3) http://t.co/g48XDpin
4) http://t.co/IiFwd6yg

Hi
I am not going to tell all the answers.Use the strategy that i taught you.Find the topic and the concept of the question.For the circuit question,trace the electricity path of each option.
For each question,you tell me the topic and the concept.Once i correct it,you could find the answer.
Cheers

I dun know how to do Q1, but my answer for Q2 is 3, answer for Q3 is 1, answer of Q4 is 3. Am I correct?[/quote]Hi
For questions 2 and 3,you are correct.I hope that you used my method.Question 4 is a tricky one but you got it right.I hope you know who gains heat and who loses heat for Q4.Q1,when i clicked it,it was a math question.That one can be solved using speed ratio and time ratio.Any way,you got the three questions correct.
Cheers

[charsen]

Recia Lim:

This question comes from PSLE booklet (Year 2007-2011) pg 122 Q24.b

Other than using a cloth to wipe the plates, suggest one way to make the plates dry even faster.

Hi
This question is testing you on your knowledge of factors affecting rate of evaporation.The factors are wind,temperature,exposed surface of the area and the humidity level in the air.Out of these,humidity and exposed surface area is ruled out as you cannot do anything with humidity and exposed surface area was mentioned in part a.Temperature is not possible to tell as if you put these plates in the microwave oven for example,and heat up for 20 seconds,the possible cause is although the plates would be dried,it would crack due to expansion of the plates.Wind,yes.The possible answer could be:
Place a fan beside the plates to dry them even faster.
Hope my explanation helps.
Cheers

[charsen]

Sunflower 2000:

Sunflower 2000:

http://i45.tinypic.com/20z7o6g.jpg[/IMG]

Can someone help to explain Q26? Answer key is 3. Thanks.
Above 2 questions are from Pei Chun SC Prelim 2012.

Can help to explain this question? Thanks. My DD told me the answer should be 1 since 1 has the biggest surface area. :imdrowning:

Hi
Your DD was correct.This is a good question as it is a bit tricky.You should see that the container in option 1 has the largest exposed surface area, throughout the experiment.The container in option c would have the same rate of evaporation in the beginning of the experiment but eventually,the rate of evaporation would be slower than before.
This is the explanation if this was a free response question.Hope it helps.
Cheers