PSLE 2009 - Science
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Kohjl
Can you share the question on the kettle, something to do with heat? Thank you -
kat:
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.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: -
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. -
my son said that science paper is easy and definitely easier then maths …well next will be the result anxiety then school posting anxiety … :!:
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caroline3sg:
This was a Paper 2 Question:Kohjl
Can you share the question on the kettle, something to do with heat? Thank you
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 -
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:
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kohjl:
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*
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 -
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
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kohjl
thank you.
There is one question about which can travel a longer distance in a desert, lizard & snake.
My girl’s ans sounds logical but I worry the way she phrased it.
2 reasons (my own words, but her meaning:)
1) snake has no legs, there is frictional force when gliding on the (hot - not sure this word was mentioned in her ans or not) sand.
Personally, I think the longer body also plays a part on its contact on larger surface of the sand.
2) lizard uses front legs to run, hind legs to push it faster. Faster must be linked to longer distance, but don’t know / didn’t state. -
atutor2001:
Oh, I did write that metal is a good conductor of heat somewhere in my exam answer. But I forgot to write it here because my mother told me to hurry up and have lunch.
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*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
From: kohjl's son
P/S: I will try to help to answer other people's questions later but I want to bathe first and then play computer. Sorry!
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