Q&A - PSLE Science

[J and J]

mlim321:

Little Einstein:

[quote=\"BeContented\"]DS says all along his understanding is :


During germination, oxygen, water & warmth is required.
But his Mindstretcher teacher says that during germination, oxygen is not required. Only when the leaves start then oxygen is required.

Errhhh....now he's confused. Anyone can help confirm?

Oxygen is definitely needed. How come Mindstretcher teaches him the wrong concept!
It is just that sunlight is needed when the first leaves appeared.

I am the main science tutor in my centre and i have been teaching Science for the last 12 years! Such mistake cannot be made! :mad:

During germination, there is no leaves, thus, no stomata is present. Without stomata, how does the seedling undergo respiration?

very confused.... please enlighten. Thanks.[/quote]
Seed gets oxygen and water via seed coat. When the seed receives water, its coat becomes softer expands and break out, seed get the oxygen in the water similar as the fish gets the oxygen in water.

All plants need oxygen for breathing/respiration to keep them alive.

[kiasuaunt]

bestwishes:

Michaelia0816:

Help! MayI know the feature of penguin's outer covering which protect it from environment and predator?

Counter-shading... Answers & explanation can be found in pg 357 qns 11 and 12 upper block sc frequently asked qns by eph (green cover with praying mantis)

Hi.

- Penguins have white bellies and black backs. This type of colouration is called counter-shading and is a form of camouflage.
- When swimming in water, the white belly of a penguin helps it to camouflage or blend in with the colour of the sky and become less visible to its predators or prey below it.
- When swimming in water, the black back of the penguin helps it to camouflage or blend in with the dark seabed and become less visible to its predators or prey above it.

[isetan]

hi,


i saw there are some past year revision papers on the topic of "Fulcrum, Lever" is covered in the exam.

School Teacher told DD this year syllabus does not cover this topic.

Wonder if this info is correct and appreciate any parents can share and reply.

Thank you.

[Little Einstein]

isetan:

hi,


i saw there are some past year revision papers on the topic of \"Fulcrum, Lever\" is covered in the exam.

School Teacher told DD this year syllabus does not cover this topic.

Wonder if this info is correct and appreciate any parents can share and reply.

Thank you.

It is already out of the syllabus since the year 2010

[dicoyote]

Hi,


Just a quick question, is Pencil Lead a conductor of electricity? Thanks

[Sun_2010]

dicoyote:

Hi,


Just a quick question, is Pencil Lead a conductor of electricity? Thanks

Yes it is.
Pencil lead is made of graphite - a good conductor of electricity.

[Michaelia0816]

Guy, help, this is the web for the photo


http://t.co/O0PUHfF8

[fightingmom]

Michaelia0816:

Guy, help, this is the web for the photo


http://t.co/O0PUHfF8

the answer is (4).

The oil prevents the leaves from losing water through the stomata. Hence, the more surface of the leaf is painted with oil, the lesser water loss for the leaf.

[Michaelia0816]

Thx for the answer and the reasons!

[Niedino]

Michaelia0816:

Guy, help, this is the web for the photo


http://t.co/O0PUHfF8

Hi Michaelia,

Fightingmom is right. To provide a more detailed explanation, more stomata is found on the underside of the leaf as compared to the top side of the leaf. Thus, there is more water loss through transpiration (causing a drop in mass) of the leaf with its bottom side covered in oil as compared to the one with its top side covered in oil.

Hence the answer is option 4 and not 2. Test your child on why it is not 2, and explain to your child using this reason.

Hope this helps!

Niedino