2010 PSLE Science

[GoldenR]

the kiasu student:

One of the questions from today's paper was like this:


A 200cm metal rod was heated for 20mins and expanded to a length of 210cm. John took another 200cm metal rod, made of the same type of metal, but thicker. He heated it for 20mins. Will the length of the thicker rod be shorter or longer than 210cm or be the same? Explain.

My answer: Longer. The amount of matter in the thicker rod was more than the amount of matter in the first rod, hence the thicker rod would expand to more than 210cm. :? :? :? :? :? :? :? :? :? :? :?

Hi, i think the ans shld be shorter as the rod is thicker, it will take longer for heat to be conducted so in 10min, the length will be shorter than 210cm.

[samy]

anon123:

I want to know ans for qns 34

It's about 'someone' is in a jungle,all the fruits and plants cant be eaten he only have the following items to produce drinkable water:
.Plastic Sheet
.Newspaper
.Towel
.String

What should he do?

Help me with this qns pls..... :idea:

my son say tie the plastic sheet,onto 4 tree.then weait until morning dew,then use the towel absorb the dew with towel then drink lorh

[kiasumum_2010]

anonymus:

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....

[GoldenR]

anonymus:

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

Same! Bcos when the rubber band turns, it moves than the propellor move and the whole plane will move. So all 3 options hav kinetic energy.

[tryunited]

kancheongmum:

Hi all


At last PSLE over for DS. Just want to share his answer for the qn where you are in the forest, given newspaper, towel , plastic sheet and string. How to get water when you are thirsty? I don't know if it is acceptable. Science tutors or teachers please give your comments. I have a good laugh. He said that his P5 Science teacher have taught him this method of getting pure water.
I feel very high tide. I urinated on the towels. Use the string to tie on both ends of plastic sheet and then tie both ends to the trees. Place the towels under the plastic sheets. The urine evaporated and water vapour condensed on the inner surface of the plastic sheet form water droplets. Collect the prue water and drink.

haha, verry funny and good try, but dun thk is acceptable as this is unlikely one of the standard answer. usu they want science concept answer.

[MOE Hater]

kancheongmum:

Hi all


At last PSLE over for DS. Just want to share his answer for the qn where you are in the forest, given newspaper, towel , plastic sheet and string. How to get water when you are thirsty? I don't know if it is acceptable. Science tutors or teachers please give your comments. I have a good laugh. He said that his P5 Science teacher have taught him this method of getting pure water.
I feel very high tide. I urinated on the towels. Use the string to tie on both ends of plastic sheet and then tie both ends to the trees. Place the towels under the plastic sheets. The urine evaporated and water vapour condensed on the inner surface of the plastic sheet form water droplets. Collect the prue water and drink.

:lol:
New Water!!

[GoldenR]

Blockbuster:

MCQ easy, but open-ended difficult. Question on toilet bowl flushing system?!

I put the bottle will sink. Than bcos the bottle occupy space so it will take less water to fill up to level L thus decreasing the amt of water used. Smthing lyk tat...

[Tapeworm]

samy:

anon123:

I want to know ans for qns 34

It's about 'someone' is in a jungle,all the fruits and plants cant be eaten he only have the following items to produce drinkable water:
.Plastic Sheet
.Newspaper
.Towel
.String

What should he do?

Help me with this qns pls..... :idea:

my son say tie the plastic sheet,onto 4 tree.then weait until morning dew,then use the towel absorb the dew with towel then drink lorh

I wrote \"He can either wait for the rain to come, or he can jog on the spot, perspire, use the towel to wipe off the sweat onto the plastic sheet then drink it up\"

[elizabethtang01.029839gmail.029839com]

My son came across this in a fiction book months back


1.\tDig a hole in the forest ground
2.\tMake a cup with the newspaper
3.\tTear the plastic sheet into two
4.\tLine the cup with the plastic sheet
5.\tPlace the cup into the hole
6.\tPlace the remaining plastic sheet over the hole and wait

(The sun will evaporate the water from the soil, and the water vapour will condense on the plastic sheet, and drip into the cup.)

Fact or fiction?? :roll:

[MOE Hater]

maxtan:

please tell me the 30 answer of the science MCQ answer THX

I think it is 2. I may be wrong