PSLE 2009 - Science

[Rainshell]

My ans is also bulb is faulty …

Gd luck to those who are takinq HMT 2moro … XD

[kohjl]

atutor2001:

PS
Sorry change my answer after seeing Kohjl's son's post. With picture of a circuit given, then \"the circuit is closed\" is likely the answer. Your reasoning is very good. Sure A*

Thank you, I hope so!

From kohjl's son

[caroline3sg]

Kohjl

Can you share the question on the kettle, something to do with heat? Thank you

[pinky88]

kat:

kuzco:

My boy said the same for every subject, \"ok lah\". :stupid: :frustrated:

at least your boy siad ok, my boy told me every subject also difficult.. :lol: :lol:

I empathize with both of u. Kids nowadays, esp. boys, do not like to share much. They are simply too lazy to talk or \"bo-chap\". My boy also said \"so-so\" for every paper until I probe further then he will tell me a bit more. So sometimes I gave up asking too much. Even though he felt the paper was easy, he will still tell me \"so-so\". His reason was cos' he is afraid his results will contradict what he says. Anyway being his mum, I usually can tell fm his tone & expression his true feeling abt the exam.. And everytime I ask him what r some of the difficult qns, his reply is always \"I forgot\". \"Chee-kek\" man :stupid: My girl (P4) on the the other hand share too much. Lucky got this forum, then can know more abt the papers. Tks to those who share the qns & ans.

[caroline3sg]

pinky88

I agree with what you said about boys not sharing as much as girls. My P1 boy never tells me what happens in sch. But he noted his sister telling me alot.

[mis]

my son said that science paper is easy and definitely easier then maths …well next will be the result anxiety then school posting anxiety … :!:

[kohjl]

caroline3sg:

Kohjl

Can you share the question on the kettle, something to do with heat? Thank you

This was a Paper 2 Question:
There were 2 pots (not kettle) filled with water, each placed on a metal plate. One metal plate had air spaces (gaps) in them, while the other did not. It was shown in the diagramme that there was \"heat\" coming from under the metal plate.

a) Which boiled faster?
My answer: The one without the air spaces (gaps).

b) Why?
My reason: As air is a poor conductor of heat, heat will move through the metal plate without air spaces faster than through the metal plate with air spaces. Thus, the pot on the solid metal plate with no air spaces will be heated up faster than the other pot on the metal plate with air spaces. So the water in that pot boiled faster.

From: kohjl's son

[concerned]

emm...for the kettle question mydaughter wrote:heat is lost tothe surrounding air for kettle b as there are holes so not much heat is conducted to kattle a,wheraes for a, there are no holes and since metal is a good conductor of heat,it boils faster.is it correct?i'm dying of suspense! :? :shock:

[atutor2001]

kohjl:

b) Why?
My reason: As air is a poor conductor of heat, heat will move through the metal plate without air spaces faster than through the metal plate with air spaces. Thus, the pot on the solid metal plate with no air spaces will be heated up faster than the other pot on the metal plate with air spaces. So the water in that pot boiled faster.

From: kohjl's son

Woh! Your concept is very clear. Maybe the only other keywords are : \"while metal is a good conductor of heat\". I think it should be a 1 mark question so your answer is more than enough. A*

[beatrice]

for the kettle question, i wrote that metal is a better conductor of heat than air, thus the metal will conduct the heat faster and the water will boil at a faster rate or something like that. that isnt my full answer by the way