2010 PSLE Science

[tiggerthong1998]

For the question on the boy in the jungle, is there any alternative answer


besides the one on transpiration ? :?

[tiggerthong1998]

Is there any other answer for the question on the boy in the jungle besides the one about transpiration? :scratchhead: :?

Many of my friends plucked a leaf,put the plastic on top and tied it with a string and when the leaf transpires,it gives out water vapour which condenses into water droplets on plastic.

[buttercookies]

DS wrote pluck leaf from tree and put in plastic sheet before tie with string. :? :?

[anonymus]

James Ang:

1. Heating the windscreen makes the windscreen's temperature higher than the temperature of surrounding water vapour so that condensation will not take place on the windscreen to make the windscreen blurry. Condensation takes place when water vapour touches a cooler surface.


2. To get water from the water vapour, I believe a cool surface needs to be formed using a waterproof sheet to collect water vapour that condenses overnight into a cup/container due to the temperature difference between cold nights and warmer early morning. This is similar to how dew is formed on leaves of plants in the morning.

3. Not sure what they ask in the exam but could the big elephant have bigger ears due to structural adaptation, to help cool down his bigger body, compared to the smaller elephant with smaller ears.

5. Could the nail have already been magnetised and stroking it one way will make it stronger while stroking it the opposite way will demagnetise the magnetic nail?

jackaljaysen:

[quote=\"anonymus\"]Hi friends,

Can u pls share yr answers 4 the follw qts:

1) Car windscreen - how can he c

2) In Forest how 2 get H20 with newspaper,string.....etc

3) Big elephant with big big ears n small ele with small ears - in forest

4) Rod b changed 2 greater thickness - effect of expansion

5) Y the nail cannot magnetised with northpole

6) Decomposition - how 2 increase?

Ok,I cannot do the second q u asked, and only one way for q6. :stupid:

My Answer:
1) Heating allows the water droplets on windscreen to evaporate,enabling him to have a clearer vision of the vehicles and pedestrians behind him.
2) Don't know.I just any how do. :stupid: :?:
3)Advantage: Ears have bigger e.s.a. , allowing the elephant to lose heat easily,keeping it cool.
Disadvantage: The rainforest is much cooler than the ___, it loses too much heat,and might die because it has not enough heat to live.
4)lesser than 210cm3. It is thicker.More heat isneeded to heat up the rod, so the expanxion is lesser.]
5) The north pole of magnet attracted the south atoms to one side of the rod,the other magnet did not have any atoms to be moved to the other side of the rod, so not sucessful.
6) I only know one way: add more decomposers and scavengers into the bin. Scavengers: To break down e smaller pieces of dead leaves into smaller pieces.
Decomposers: To break down e smaller pieces of dead leaves into simpler forms.

Just hope the answers above r correct.

JJ[/quote][/quote]

Thank u all.
Hi James...I got 1 ans wrong...the dew concept .I just answered in this way..any mark will b gn?

Pluck leaf from the bushes in the forest n place them on the pile of the newspaper.USe the string to tie from one end of the bark to the other end and hang the palstic sheet over it. Place a stone on the plastic sheet so tht the dent is made. The leaves will transpire n produce water vapour tht will come in contact with the inner surface of the plastic sheet n condense 2 form water droplets.Collect these water droplets using the large leaf.(PS: Leaves were not gn as the aparatus to b used but it was mentioned tht it is in forest with only a towel , string, plastic sheet and newspapers..)

[tiggerthong1998]

Do you think moe wil accept other ans ?

[Powermum]

Whatever it is, it's almost to celebrate after tomorrow's HCL...

Tomorrow : let's :celebrate:

November : let's

[tiggerthong1998]

What did ya'll put for the magnet question in pp2 and pp1 the question where there were 3 containers ,one with a plant ,one with carbon dioxide and the last one air ?

[anonymus]

tiggerthong1998:

What did ya'll put for the magnet question in pp2 and pp1 the question where there were 3 containers ,one with a plant ,one with carbon dioxide and the last one air ?

is the ans (1)

[snowman.022851697]

Tough... :stupid:

[anonymus]

anonymus:

James Ang:

1. Heating the windscreen makes the windscreen's temperature higher than the temperature of surrounding water vapour so that condensation will not take place on the windscreen to make the windscreen blurry. Condensation takes place when water vapour touches a cooler surface.


2. To get water from the water vapour, I believe a cool surface needs to be formed using a waterproof sheet to collect water vapour that condenses overnight into a cup/container due to the temperature difference between cold nights and warmer early morning. This is similar to how dew is formed on leaves of plants in the morning.

3. Not sure what they ask in the exam but could the big elephant have bigger ears due to structural adaptation, to help cool down his bigger body, compared to the smaller elephant with smaller ears.

5. Could the nail have already been magnetised and stroking it one way will make it stronger while stroking it the opposite way will demagnetise the magnetic nail?[quote=\"jackaljaysen\"]

Thank u all.
Hi James...I got 1 ans wrong...the dew concept .I just answered in this way..any mark will b gn?

Pluck leaf from the bushes in the forest n place them on the pile of the newspaper.USe the string to tie from one end of the bark to the other end and hang the palstic sheet over it. Place a stone on the plastic sheet so tht the dent is made. The leaves will transpire n produce water vapour tht will come in contact with the inner surface of the plastic sheet n condense 2 form water droplets.Collect these water droplets using the large leaf.(PS: Leaves were not gn as the aparatus to b used but it was mentioned tht it is in forest with only a towel , string, plastic sheet and newspapers..)

[/quote]Any expert can reply to this?//