Q&A - PSLE Science

[tianzhu]

ms_lim:

Ans key : chemical potential engergy --> Kinetic energy + Sound energy

My dd's ans : Kinetic energy --> Heat sound + Sound energy

Hi

I think you need to begin with chemical energy.

Assuming the ball is given a push with the arm of a pupil.

The potential energy from the food consumed is transferred to the arm, as the arm moves it has kinetic energy. The arm then transfers the kinetic energy to the ball. As the ball rolls, part of the KE is converted to heat and sound energy.

Chemical Potential Energy ------ KE + either Heat or Sound.

Best wishes

[millan]

vidhyalog:

ms_lim:

Need help to explain this question. Ans key is (2) but my dd's ans is (4).

http://i56.tinypic.com/168itqc.jpg\">

My son also got (4). (2) is nonsensical.

I think it is 2, because when the plants convert the liquid into gas, it will help with evaporation so that the water cycle can continue

[andante]

vidhyalog:

ms_lim:

[quote=\"andante\"]Hi all,

My dd has done edgefield science paper and there are discrepancies between the answer keys and her answers. Can someone help ?

Q11 (3) but answer key is (4)
Q12 (4) but answer key is (2)
Q13 (2) but answer key is (1)
Q14 (2) but answer key is (1)
Q16 (3) but answer key is (2)

Thanks.

Dear Andante, below are my dd's ans
Q11 - 3
Q12 - 4
Q13 - 2
Q16 - 3
Q14 - 1 Ans key is 3
Need help on which is correct ans.

My son got same answers as your daughter.[/quote]Sorry sorry, I typed wrongly, Q14 my dd's answer is (1) and answer key is (3)

[andante]

vidhyalog:

Hi adante,


My son got the same asnwers as your dd except question 14 - for which his answer is (1). (the answer key we have showed answer as (3))

Besides these - there were also discrepancies in the following:

No3 - His answer (1) - answer key (2)
5. His answer (4 ) answer key (2) - which does not make sense at all.

Did your dd get these answers for 3 and 5.

Hi vidhyalog,
my dd's answers for Q3 is (2) same as the answer key as it is the female reproductive cell in plants.

As for Q5, initially, she also chose (4) ... i.e. photosynthesis and stored as food. but that does not seem to affect the environment so she chose (2) as she thought it may have something to do with the humidity. Actually, I agree with you on the option (4) but I am not sure how it affects the environment of a habitat.

[Alchemist]

andante:

vidhyalog:

Hi adante,


My son got the same asnwers as your dd except question 14 - for which his answer is (1). (the answer key we have showed answer as (3))

Besides these - there were also discrepancies in the following:

No3 - His answer (1) - answer key (2)
5. His answer (4 ) answer key (2) - which does not make sense at all.

Did your dd get these answers for 3 and 5.

Hi vidhyalog,
my dd's answers for Q3 is (2) same as the answer key as it is the female reproductive cell in plants.

As for Q5, initially, she also chose (4) ... i.e. photosynthesis and stored as food. but that does not seem to affect the environment so she chose (2) as she thought it may have something to do with the humidity. Actually, I agree with you on the option (4) but I am not sure how it affects the environment of a habitat.

for Q3 - my son reasoned that the female reproductive cell should be the egg - and this cell is housed in the ovule. I will try and post the Q on KSP to see what other parents say.

[tisha]

http://i53.tinypic.com/33wxv7o.jpg\">


This Q is from RGPS Q21 Prelim 2011.

The answer key says 1 (C only) as the answer. Could someone confirm this and explain why? :please:

[millan]

ms_lim:

Need help to explain for part (c) of this question :

http://i56.tinypic.com/148p2ec.jpg\">
Ans key : chemical potential engergy --> Kinetic energy + Sound energy
My dd's ans : Kinetic energy --> Heat sound + Sound energy

There is Chemical Potential Energy as the energy that is used to push the ball comes from the person pushing it, as Chemical potential energy = the energy stored inside our body, so the person who pushes the ball converts the CPE stored in his body -> KE -> SE (We can hear the sound when the ball hits the bowling ball down. If there is and extra box, put heat energy

Hope this helps

[Alchemist]

tisha:

http://i53.tinypic.com/33wxv7o.jpg\">


This Q is from RGPS Q21 Prelim 2011.

The answer key says 1 (C only) as the answer. Could someone confirm this and explain why? :please:

My son said B&C. As we do not know how much water was there before the ruler was put in - we cannot find A.

[andante]

vidhyalog:

for Q3 - my son reasoned that the female reproductive cell should be the egg - and this cell is housed in the ovule. I will try and post the Q on KSP to see what other parents say.

You are right that the question is about the cell so I think it should be egg lor.

[Publica]

vidhyalog:

tisha:

http://i53.tinypic.com/33wxv7o.jpg\">


This Q is from RGPS Q21 Prelim 2011.

The answer key says 1 (C only) as the answer. Could someone confirm this and explain why? :please:

My son said B&C. As we do not know how much water was there before the ruler was put in - we cannot find A.

Hi,
The answer should be C only. Since A was not fully submerged in the water, we cannot find the volume of B when both A and B are put into the beaker.