Q&A - PSLE Science

[Robertpattinsonidle]

verykiasumummy:

using another magnet to chk if it repels is not required to confirm if they have become temperary magnets, (only when u need to confirm an object is a magnet, as in permanent magnet) because temporary magnets are just for short term, so the repulsion may not be guaranteed.

i tried that at home.

[Robertpattinsonidle]

Robertpattinsonidle:

verykiasumummy:

using another magnet to chk if it repels is not required to confirm if they have become temperary magnets, (only when u need to confirm an object is a magnet, as in permanent magnet) because temporary magnets are just for short term, so the repulsion may not be guaranteed.

i tried that at home.

it doesnt actually work.

[Robertpattinsonidle]

Robertpattinsonidle:

Robertpattinsonidle:

[quote=\"verykiasumummy\"]using another magnet to chk if it repels is not required to confirm if they have become temperary magnets, (only when u need to confirm an object is a magnet, as in permanent magnet) because temporary magnets are just for short term, so the repulsion may not be guaranteed.

i tried that at home.

it doesnt actually work.[/quote]i did about 50 strokes but the temporary magnet still is not as strong enough as needed in order to repel a magnet. thanks
Cheers! :roll:

[charsen]

verykiasumummy:

charsen:

[quote=\"Robertpattinsonidle\"]my answer is 3. answer key says 2. any explanantion? http://i46.tinypic.com/fadmj6.jpg\">

Hi
The answer is 3.No doubt that water conducts very little heat to the ice since water is a poor conductor of heat.But before the heat reaches the water first,the test tube would gain heat and heat would travel throughout the test tube.Thus,heat also travles to the bottom of the test tube.Since the ice is wrapped with wire gauze,it is an insulator of heat and prevents ice from melting from the boiling water.
Please confirm the answer.
Charsen.

hi, sorry but ans should be 2, not 3. the wire gauze just prevents heat from reaching the ice too easily, in other words, it reduces the heat travelling to the ice, hence ice melts slower. but A states the wire gauze prevents heat from reaching the ice so technically the statement is wrong.

my ds last yr got caught at a similar question. if use prevent, must use with \"prevent....easily...\" if not use \"reduce....\" (den dun need to put easily)

hope it clarifies... i'm just sharing what the sci teacher says...[/quote]Hi
Thank you for the sharing.I learnt something new today.
Charsen.

[Zhu99]

Robertpattinsonidle:

my answer is 3. answer key says 2. any explanantion? http://i46.tinypic.com/fadmj6.jpg\">

The answer key 2 is correct.

The purpose of the wire gauze is to keep the ice at the bottom of the test tube. (Wire gauze is a good conductor of heat).

The experiment basically shows that water is a poor conductor of heat. [Note: Water is a good conductor of electricity. Normally a good conductor of heat is also a good conductor of electricity.]

[GLORYmum]

Tao Nan 2012 Prelim Q11 is the answer 1 or 2.

TIA.

[verykiasumummy]

Robertpattinsonidle:

verykiasumummy:

using another magnet to chk if it repels is not required to confirm if they have become temperary magnets, (only when u need to confirm an object is a magnet, as in permanent magnet) because temporary magnets are just for short term, so the repulsion may not be guaranteed.

i tried that at home.

it doesnt actually work.[/quote]
i did about 50 strokes but the temporary magnet still is not as strong enough as needed in order to repel a magnet. thanks
Cheers! :roll:[/quote]

thks for trying out... i nv did tried... i basically only go thru the text and guides with my ds last time... going to teach my dd and youngest ds again soon....

[verykiasumummy]

charsen:

verykiasumummy:

[quote=\"charsen\"]
Hi
The answer is 3.No doubt that water conducts very little heat to the ice since water is a poor conductor of heat.But before the heat reaches the water first,the test tube would gain heat and heat would travel throughout the test tube.Thus,heat also travles to the bottom of the test tube.Since the ice is wrapped with wire gauze,it is an insulator of heat and prevents ice from melting from the boiling water.
Please confirm the answer.
Charsen.

welcome charsen...

just exchanging views... we learn from each other...
hi, sorry but ans should be 2, not 3. the wire gauze just prevents heat from reaching the ice too easily, in other words, it reduces the heat travelling to the ice, hence ice melts slower. but A states the wire gauze prevents heat from reaching the ice so technically the statement is wrong.

my ds last yr got caught at a similar question. if use prevent, must use with \"prevent....easily...\" if not use \"reduce....\" (den dun need to put easily)

hope it clarifies... i'm just sharing what the sci teacher says...

Hi
Thank you for the sharing.I learnt something new today.
Charsen.[/quote]

[verykiasumummy]

welcome charsen…


just exchanging views… we learn from each other…

(ps. dunno why the post looks funny, maybe i type at the wrong plc… )

[balu_priya]

Please help.


1)which one of the following statements Best describes a characteristic of living things?
1.living things cannot survive in the absent air.

Living things may have the ability to give birth to young ones.alive
Living things move from place to place in search of food.
Living things can live in the presence of large amount of water.



2.two ice cubes were stacked and a pushing force exerted from the top. After one minute , both ice cubes could be lifted off the surface by just
Holding the top of ice cube.

The process that resulted in the ice cubes 'sticking’together is/are …
1.melting
2.freezing
3.melting and freezing
4.evaporation and freezing