PSLE 2009 - Science

[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!

[tutormum]

Hi Kohjl,

Which school is your son in? Does he want to go to RI? My son shares the same interests as yours and his best friend is also very good in Science (he top his prelim). How I wish both our sons are friends cos I'm sure my son has a lot to learn from him. My son's problem is being stubborn in his thinking and unless you can convince him, he'll refuse to listen. :x He believe in Mythbusters more than what I say. :lol: I'm hoping he'll get into RI but I'll be stressed if he does.

[chk707]

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 ?

Thats true. I was also confused when my son asked me this question, but i found out that catapillars grow into butterflies and helps to pollinate the flowers. Without pollination, the flowers of the plants will not get fertilised and could not transform into a fruit. So i think the answer is Vegetable increase, Fruits decrease.

[PlasmaStorm]

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.

Thank you!

(Formerly kohjl Jr )

From: PlasmaStorm

[caroline3sg]

justsay

yes, I am referring to the same question. I am just stating the reason why my girl put veg decrease, fruit trees decrease.

[acelancer]

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.

the pic of the adding a bulb parallel to one of the bulbs in series question was not like tht. it was another way... but similar.(a small difference may make a great differrence)

[Augmum]

My gal also mentioned the diagram looks different. according to her, the added parallel bulb is in the middle and the connection of the wire is extended and connected to the right side (something like that).


any pupil here remembers the exact diagram drawn.

[tutormum]

Can anybody provide the question on anther and stigma thingy? Thanks