2010 PSLE Science

[anonymus]

beauty queen:

Polar bear:

Thanks.

One of my suggestions for the decomposition question was to put the jar in a dark room and my reason was that it would allow more decomposers to come into the jar, thus speeding up decomposition.

Can someone tell me if this is acceptable

No i do not think so. As the rotten log habitat or the leaf litter habitat is dark i am not sure darkness is a factor for the growth of decomposers

just my 2 cents

One of the factors for Rotting log habitat is dampness n darkness. So, i think polar bear ans is correct

[MOE Hater]

ApronMama:

Polar bear:

anybody know the answer to the insect X question. I put 28 days but many of my friends say that it is 24 days and what is the reason for insect X staying in water for the egg larva and pupa stages

I feel that it is 24 because the question said \"after the egg hatched\" ,so it should not include the time insect x stayedin the egg stage. :lol: :lol: :lol:

Thot 28 was excluding the egg stage!!!! I put 28! :shock:

[triplediao]

mrswongtuition:

Little Mermaid:

For the elephant question, I put :

The big ears help to trap air which is a poor conductor of heat.Thus,keeping the elephant cool. Wonder if it is correct!!! :?: :!:

Big ears do help to keep the elephant cool.
However, it is not due to the trapped air but the large surface area for them to lose the heat.

I didn't mention large exposed surface area. I mentioned about the large number of blood vessels found in the ear of the elephant A helping it to conduct heat away from its body. O.o Oops

[thensingsmysoul]

anonymus:

beauty queen:

[quote=\"Polar bear\"]Thanks.

One of my suggestions for the decomposition question was to put the jar in a dark room and my reason was that it would allow more decomposers to come into the jar, thus speeding up decomposition.

Can someone tell me if this is acceptable

No i do not think so. As the rotten log habitat or the leaf litter habitat is dark i am not sure darkness is a factor for the growth of decomposers

just my 2 cents

One of the factors for Rotting log habitat is dampness n darkness. So, i think polar bear ans is correct[/quote]Based on my mini 'research', darkness is not a factor that contributes to speeding up decomposition.

The answer is dependent on how the question is asked, but basically, the rate of decomposition is dependent upon:
* Temperature (the warmer the better);
* The availability of oxygen;
* Access by scavengers;
* Humidity, or wetness;
* Rainfall/Dampness;
etc...

[MOE Hater]

But must make sure temp not too high, or else bacteria all die and decomposition slowed down

[mum-in-action]

MOE Hater:

ApronMama:

[quote=\"Polar bear\"]anybody know the answer to the insect X question. I put 28 days but many of my friends say that it is 24 days and what is the reason for insect X staying in water for the egg larva and pupa stages

I feel that it is 24 because the question said \"after the egg hatched\" ,so it should not include the time insect x stayedin the egg stage. :lol: :lol: :lol:

Thot 28 was excluding the egg stage!!!! I put 28! :shock:[/quote]Hi, can someone share the answer for this insect X question,part b? The question is insect X has wings,which stage of insect X lives in the water/

[beauty queen]

thensingsmysoul:

anonymus:

[quote=\"beauty queen\"]
No i do not think so. As the rotten log habitat or the leaf litter habitat is dark i am not sure darkness is a factor for the growth of decomposers

just my 2 cents

One of the factors for Rotting log habitat is dampness n darkness. So, i think polar bear ans is correct

Based on my mini 'research', darkness is not a factor that contributes to speeding up decomposition.

The answer is dependent on how the question is asked, but basically, the rate of decomposition is dependent upon:
* Temperature (the warmer the better);
* The availability of oxygen;
* Access by scavengers;
* Humidity, or wetness;
* Rainfall/Dampness;
etc...

:)[/quote]
phew! I put put the bin in a warm habitat

[the kiasu student]

Polar bear:

Thanks.

One of my suggestions for the decomposition question was to put the jar in a dark room and my reason was that it would allow more decomposers to come into the jar, thus speeding up decomposition.

Can someone tell me if this is acceptable

You are half right and half wrong. I also said that should put it in a dark place, but not to attract decomposers nor allowing more of them go into the jar. This will reduce the rate of evaporation of the moisture from the moist leaves, hence more moisture is kept, as decomposers need water to decompose dead organisms, this would speed up decomposition.

[MOE Hater]

MOE Hater:

ApronMama:

[quote=\"Polar bear\"]anybody know the answer to the insect X question. I put 28 days but many of my friends say that it is 24 days and what is the reason for insect X staying in water for the egg larva and pupa stages

I feel that it is 24 because the question said \"after the egg hatched\" ,so it should not include the time insect x stayedin the egg stage. :lol: :lol: :lol:

Thot 28 was excluding the egg stage!!!! I put 28! :shock:[/quote]Does anyone know???!!! :idea:

[triplediao]

Kiddo98:

cocoong1998:

[quote=\"Blockbuster\"]MCQ easy, but open-ended difficult. Question on toilet bowl flushing system?!

MCQ most were easy but erm a few were quite tricky! Section B was in the middle of tough and ok ok ! the question on toilet flushing i put >the stones in the plastic bottle occupy space and the water level will reach Level L quicker. less water will be used<sth>Matter occupies space< hope this helped!

Did you say that the stones helped it to sink? I did :)[/quote]Read this is a \"Voices\" magazine they sent to my house some time ago. They didn't state the reason but it was to increase the level L in order to reduce amount/volume of water used to flush the toilet and more refilled back into the tank. At least that was my way of phrasing.
Hope this helps:)

Don't think to much about it. It's over and there is nothing you can do about it. Just go relax! Unless you have HMT like me tomorrow la, then wait 1 more day.