PSLE 2009 - Science

[atutor2001]

kohjl:

The Question:
The farmer found that alot of caterpillars were eating his crops. The farmer sprayed alot of pesticides onto them. Which of the following is correct?

My answer:
Crops-increased
Fruits-increased

Reason: Even if the pesticides kill some of the plants, pesticides will kill most of the caterpillars. Since there are no more caterpillars feeding on the leaves, the number of crops will increase and therefore, the number of fruits will increase.

From: kohjl Jr

[/quote]

Hi Kohjl Jr, is there an option for both crops and fruits to decrease, if yes, I will pick that option.

The words \"alot of pesticides\" may imply that some of the crops will be killed by the pesticides.

[atutor2001]

kohjl:

....When 2 equal forces are acting on each other in opposite directions, the resultant force is 0 as the magnetism cancels out the force of gravity.....


From kohjl Jr

Your answer fit that of a Sec student. You need not take PSLE :celebrate:

[atutor2001]

Hi Kohjl (Mummy)


I have not seen better answers than those from your son. His concept is clear and his answer is precise. Your are so blessed.

[eddie tan]

Aya:

What did everyone put for the first question? Some people in my class say that the ans is either 2. Stomach or 3. Small Intestines.


And how about the last question for Booklet B? That one was tough...

So, how many questions have everyone confirmed wrong for Booklet A? For me, already 2 questions Overall, I don't think the paper was easy at all... of course an exception for the science freaks out there.

i think my son has at least 5 Q answered wrongly [AT LEAST] NO HOPE 4 HIM TO GO TO DREAM SCHOOL ALREADY LOH GANNASAI :oops: :oops:

[mew2]

caroline3sg:

mummyjamie & sahimi


my girl said biceps/triceps (is labelled as one letter) & the other one is the fulcrum - the elbow. So it is P & R?

friends,

my little one's ans is P and R
reason she gave is:

there were 2 diagrams
first one, a person holding the dumbbell, arms outstretched
and the second diagram, elbows bent, lifting the weight
question : which of the following is required to result in the second diagram (something like that)

key is what enabled diagram one to diagram 2

the other common ans is p q r , including the lower arm

:?

[mew2]

justsay:

hot_chocolate:

paper is easier than maths...


there's a question on circuits in booklet A... about the one with the light bulb that felt warm and did not light up.

anybody knows if the answer is:
1)the light bulb is faulty
2)the circuit is closed

this question is tricky. a lot of people have different answers, mainly this two. does anyone remember the exact question???? :frustrated:

It could be bulb faulty and it could also be circuit is closed but insufficient energy source, depending on the question. Need to know the exact question.

one possibility if faulty bulb;
there could be a short circuit, causing a brief surge in current, causing the heat in the bulb.

need to know question

:?

[justsay]

I cant upload the picture. Keep giving me timeout error.


Goto http://www.pslescience.blogspot.com

If the question on adding a bulb parallel to one of the bulbs in series was drawn this way, I would agree that the answer should be (2) would be brighter.

[caroline3sg]

There was a question in the PSLE Science thread in this forum which ask which brand of pesticide P, Q, R, S is effective. All options are decrease, the ans is to choose the option which crop decrease the least & pests decrease the most.


So based on this, my girl’s ans to the PSLE question is decrease/decrease. Of course, the reason supporting this ans is not as logical as kohjl jr, but "spraying a lot of pesticides" will sure do some damage to the veg and if fruit trees are sharing the same plot of land, the soil would also have pesticides.

[justsay]

caroline3sg:

There was a question in the PSLE Science thread in this forum which ask which brand of pesticide P, Q, R, S is effective. All options are decrease, the ans is to choose the option which crop decrease the least & pests decrease the most.


So based on this, my girl's ans to the PSLE question is decrease/decrease. Of course, the reason supporting this ans is not as logical as kohjl jr, but \"spraying a lot of pesticides\" will sure do some damage to the veg and if fruit trees are sharing the same plot of land, the soil would also have pesticides.

The Question:
The farmer found that alot of caterpillars were eating his crops. The farmer sprayed alot of pesticides onto them. Which of the following is correct?

My answer:
Crops-increased
Fruits-increased

Reason: Even if the pesticides kill some of the plants, pesticides will kill most of the caterpillars. Since there are no more caterpillars feeding on the leaves, the number of crops will increase and therefore, the number of fruits will increase.

From: kohjl Jr



Hi caroline3sg,
Are you talking about the same question or another question ?

[kohjl]

atutor2001:

Hi Kohjl (Mummy)


I have not seen better answers than those from your son. His concept is clear and his answer is precise. Your are so blessed.

Hi atutor2001

Thank you for your kind comments.

My son loves Science, and he enjoys having discussions with his brother (Year 4, RI) so I guess that's how he picks up many Science concepts. He also enjoys reading National Geographic mags and the like, and his favourite TV channel is Discovery channel. He just loves Mythbusters!

Just a clarification in case anyone is wondering: the scientific reasoning he writes about in each of his forum postings is entirely his own; I don't even edit it. I only add to the part under \"The Question\" to make it clearer to readers cos I have the benefit of having my son draw the diagram for me, while readers don't. It is to help parents better understand the question. Other than that, all answers are his own.

Thanks again for your encouragement. And yes, I feel very blessed - not only because of this son, but by my whole family!