Q&A - PSLE Science

[cimman]

pertunia:

I thought only leaves have chloroplast since only leaves have chlorophyll and make food? Balsam stem cell also have chloroplast? Please enlighten me. Thanks a lot.

some stems do have chloroplasts and produces food.
check out this link and scroll to Page 165, bottom section: Photosynthetic Stems: http://www.edupub.gov.lk/Scieence%208%28E%29/Chapter%206.pdf
also check out this pic of a balsam plant and it does have green stem: http://home-and-garden.webshots.com/photo/1181052099042988353KaBRFn

the key question though is why do some plants have photosynthetic stems ? Cactus have it because their leaves are a spindle and does not have the surface area to produce food. But the balsam plant have good broad green leaves which produces food, so why the photosynthetic stem ?

I found an article on this, it's very dry though and unfortunately, you have to pay for the entire article:
http://www.jstor.org/discover/10.2307/2389755?uid=3738992&uid=2129&uid=2&uid=70&uid=4&sid=56245820003

[pertunia]

Hi Cimman,


Thanks for the information. Really appreciate it a lot.

[Champion]

First step --1st - the child needs to be careful in reading the questions. Highlight the keyword in the question, then analyse the given choice. I share here one question that was in my P4 DD1 SA1 MCQ.


Which of the following is definitely true about plants?
A) ALL plants start their life cycles from seeds.
B) Plants reproduce to ensure the survival of their kinds.
C) Seeds need oxygen, water and sunlight to germinate.

(1) A only
(2) B only
(3) A and B only
(4) A, B and C

DD1 highlighted the keywords (as I done above) and then proceed to eliminate her answers by striking off (1) & (4). So left (2) & (3) then \"unconsciously\" she forgotten to strike off (3) and \"conveniently\" puts her answer as (3) when the correct answer is (2)! :frustrated: :stompfeet: :slapshead: :mad:

The Science T has let the class tried similar questions a few times, but this question is a little rephrase and concept changed and so my dear DD1 careless mistakes that cost her to lose this precious 2 marks :sad:

[Chan09]

Need help on this as answer key is 1.


My understanding is lead is a conductor of electricity and D is a closed circuit.



http://i50.tinypic.com/1zxy14y.jpg\">

[isetan]

Chan09:

Need help on this as answer key is 1.


My understanding is lead is a conductor of electricity and D is a closed circuit.



http://i50.tinypic.com/1zxy14y.jpg\">

Hi chan09,

My ans is (3). Option B has no batteries, option D has a parallel loop, and I also agree lead is a conductor of electricity.

[G Tan]

Chan09:

Need help on this as answer key is 1.


My understanding is lead is a conductor of electricity and D is a closed circuit.


My answer is also 3
http://i50.tinypic.com/1zxy14y.jpg\">

[BeContented]

Confirm liao.


If I re-take PSLE, I will sure fail Science and probably just border pass for Maths cos dun have the speed.......
:faint: :oops:

[cimman]

Champion:

First step --1st - the child needs to be careful in reading the questions. Highlight the keyword in the question, then analyse the given choice. I share here one question that was in my P4 DD1 SA1 MCQ.


Which of the following is definitely true about plants?
A) ALL plants start their life cycles from seeds.
B) Plants reproduce to ensure the survival of their kinds.
C) Seeds need oxygen, water and sunlight to germinate.

(1) A only
(2) B only
(3) A and B only
(4) A, B and C

DD1 highlighted the keywords (as I done above) and then proceed to eliminate her answers by striking off (1) & (4). So left (2) & (3) then \"unconsciously\" she forgotten to strike off (3) and \"conveniently\" puts her answer as (3) when the correct answer is (2)! :frustrated: :stompfeet: :slapshead: :mad:

The Science T has let the class tried similar questions a few times, but this question is a little rephrase and concept changed and so my dear DD1 careless mistakes that cost her to lose this precious 2 marks :sad:

I look for the keyword ALL. All means 100%, there are no exceptions, not even 99%. In nature, or even in physical science, it is very rare that there are no exceptions. Anything with ALL is most likely wrong. It's a guideline only, works most of the time though.
The best way is of course, to have a good understanding of the concepts. However, guidelines are good to flag out possible careless mistakes, makes the child think twice when the guideline is violated.

[notfreemom]

Please help! Why the weight will move to pole Y but not X?

Thanks
http://i48.tinypic.com/11wdpvq.jpg\">

[Nebbermind]

notfreemom:

Please help! Why the weight will move to pole Y but not X?

Thanks
http://i48.tinypic.com/11wdpvq.jpg\">

Perhaps the wire will extend/expand due to the heating and sag....and the weight will slide towards the midpoint between the 2 poles, ie, towards Y