Q&A - PSLE Science

[Guitar]

ss501:

hi,

The answer given is 4, pls help to explain, thanks.
http://i51.tinypic.com/2ufaib7.jpg\">

Water evaporates at different temperatures.So, 4 is the correct ans.

[bcs-dad]

Hi All,


For the question below (for question part a), the answer key is \"Oxygen\". Can some body please explain this?

My DS answer is Carbon dioxide.

http://i51.tinypic.com/x1wwat.png\">

Thanks in advance..

[Newkiasu2011]

Does CFC cause global warming?


CFC causes ozone layer depletion. Ozone is a green house gas and causes global warming. If CFC reduces ozone, then does it mean that CFC does not affect global warming.

I read that CFC itself is a greenhouse gas. In that case, it should cause global warming.

[Nebbermind]

Newkiasu2011:

Does CFC cause global warming?


CFC causes ozone layer depletion. Ozone is a green house gas and causes global warming. If CFC reduces ozone, then does it mean that CFC does not affect global warming.

Think CFC is the greenhouse gas and not ozone. It depletes the ozone layer which in turn allow more of the sun's energy to reach the earth.

[Newkiasu2011]

thanx


http://en.wikipedia.org/wiki/Greenhouse_gas
The above link mentions ozone as one of the gh gas. Hence confusing. I agree that ozone layer reduces the sun's heat and UV rays from reaching earth.

[Nebbermind]

atutor2001:

But option (4) specifically stated \"....but not in flask A\".

For science, this is a very strong statement and it would mean that not a tiny bit of milkiness is allowed in A.\"

I go for (1)

CO2 is a trace gas. While there may be precipitation (is that the right word?), I believe it's not enough to turn the water milky. I'll got for (4)

[ms_lim]

Please help on this question :


http://i53.tinypic.com/o54xh2.jpg\">

Ans key : (1), dd's ans : (3)

[ms_lim]

Please help on part (b) :

http://i52.tinypic.com/9kvwug.jpg\">

[Newkiasu2011]

ms_lim:

Please help on this question :


http://i53.tinypic.com/o54xh2.jpg\">

Ans key : (1), dd's ans : (3)

B is elastic potential energy

[BOOMZ]

I don’t see anything wrong with your dd’s answer….