2010 PSLE Science

[snowman.022851697]

Maybe she ran out of time. Poor girl… I remember there was a time a few years back when I made a transfer error in a paper and I got like, 24/60, because when I discovered it, it was too late and I could only change a few.

[RainyDay]

kiasumum_2010:

anonymus:

[quote=\"tryunited\"]what is the answer on the MCQ qn on aeroplane, propellor and rubber band, which part(s) has/hv kinetic energy?


wing / propellor / rubber band

i put the option which had all the 3..wing, propellor and ruber band

i thought it should be the propellor only as the rubber band came to a standstill before it went into the air....[/quote]For me i also put all 3.Because i still remember my teacher told me that when something moves,it has kinetic energy even though that object is not a converter of energy.So i think the aeroplane is 4.You should check it out nevertheless i am wrong

[RainyDay]

ZoeyTan:

i think my answers are totally wrong....

could u all see whether it is acceptable?

My answer: he should water the plant daily as with more moisture,decomposition can take place faster.

he could increase the number of holes at the lid so that more oxygen could enter the bin. with more oxygen, the rate of decomposition will be higher.

(i felt that it is totally wrong)....

another thing...about the forest one..what he is thirsty then the plants and fruits could nt be eaten that one... i wrote he could cover the leaves of the plant with the plastic sheet using the string.As the plant repire, it gives off water vapour through its stomato. As the water vapour condenses onto the cooler inner surface of the plastic sheet, it will become water droplets. The boy can drink the water droplets..

and another thing ...about the toilet...
i wrote as the plastic bottle occupy space, it will take up some space in the tank, therefore, lesser water is needed to fill up the tank

b) Solid occupies space..(it is wrong?i should write matter right?)

For me i put he can poke more holes into the container allowing decomposition to take place faster and also make the lid of the container out so that bacteria can make decomposition faster

[RainyDay]

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.

I don't really know whether this is correct or not but i decide to play safe by not putting that the dark is a factor in resulting the speed of the decomposition.

[atutor2001]

RainyDay:

the kiasu student:

[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

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.

I don't really know whether this is correct or not but i decide to play safe by not putting that the dark is a factor in resulting the speed of the decomposition.[/quote]I do not know what is the question. However, it appears to do with how to increase the rate of decomposition. In my opinion, the rate can be increased if :

1. We make it easier for decomposer to break down the dead organism into simple substances by :

(a) Cutting the dead organism into smaller pieces
(b) Introduce helper of decomposer to break down the dead organism into smaller pieces.

2. Increase the number of decomposer (I think this is what the question is asking)
(a) Expose the dead organism to more decomposer by not covering it.

(b) Provide conditions for the decomposer to multiply quickly :
(i) Temperature (Warm but not too hot)
(ii) Oxygen
(iii) Moisture
(I don't remember that light is a critical factor. Light may cause overheating that cause the dead organism to dry up)

[cynnedcynner]

Does anyone know the exact way that jungle survival related question is phrased?


thanks!