Q&A - P3 Science

[ApronMama]

ET-PH:

divanhot,


Not sure whether I am correct, hang the magnet freely with a string to get the North - South pole and use the map to navigate out the jungle.

Confirmed this answer with my P3 child.

[sashimi]

ApronMama:

ET-PH:

divanhot,


Not sure whether I am correct, hang the magnet freely with a string to get the North - South pole and use the map to navigate out the jungle.

Confirmed this answer with my P3 child.

There is one more factor, just for trivia's sake - although the magnet will align itself towards N-S, you can't tell exactly which end is north unless you first determine where East-West is. So it's impt to know that if N is 12 o'clock, west is then 9 o'clock and east is 3 o'clock.

To find east-west, one can use the sun as a guide, or even the constellations.

[sashimi]

jesschan:

Dharma:

Hi jesschan,


Compare the hardness of the chalk and eraser.A chalk has a better ability to withstand scratches compared to an eraser.

The eraser will have a deeper scratch.

Thanks.

Paiseh, I disagree..... rubber is elastic in nature, and therefore resists scratches.... by reversible deformation. I.e. the spoon will change the shape of the eraser but after the spoon is removed, the eraser simply \"reverts\" back to its original shape. On the other hand, chalk is brittle and simply snaps/fractures under pressure, so will suffer a visible and permanent scratch.

[ChiefKiasu]

sashimi:

Paiseh, I disagree..... rubber is elastic in nature, and therefore resists scratches.... by reversible deformation. I.e. the spoon will change the shape of the eraser but after the spoon is removed, the eraser simply \"reverts\" back to its original shape. On the other hand, chalk is brittle and simply snaps/fractures under pressure, so will suffer a visible and permanent scratch.

Yes, I agree with sashimi on this point too.

[acforfamily]

Hi, can someone advise on this p3 question?


3 similar containers
A- has a cover and a lump of food inside
B - has no cover and food is covered with oil
C - has a cover and a small cup of water next to the food ( but not touching food)

Qn a) what would you observe after a few days?
b) what can you conclude from this experiment?

Thanks in advance.

[tianzhu]

acforfamily:

Hi, can someone advise on this p3 question?


3 similar containers
A- has a cover and a lump of food inside
B - has no cover and food is covered with oil
C - has a cover and a small cup of water next to the food ( but not touching food)

Qn a) what would you observe after a few days?
b) what can you conclude from this experiment?

Thanks in advance.

Hi, I cannot pinpoint the exact topic because I don’t have a copy of the latest Lower Block Science. If you craft your answer around moulds forming on the food, you should probably be on the right track.

Likely Observation
There are more moulds in the lump of food in container C because of higher moisture content.
You could see lesser amount of mould in the lump of food in container A as compared to container C
As for container B, the layer of oil prevents exchanges of gases , hence likely no formation of mould.

Conclusion
Moisture and oxygen must be present to support mould growth.

[atutor2001]

acforfamily:

Hi, can someone advise on this p3 question?


3 similar containers
A- has a cover and a lump of food inside
B - has no cover and food is covered with oil
C - has a cover and a small cup of water next to the food ( but not touching food)

Qn a) what would you observe after a few days?
b) what can you conclude from this experiment?

Thanks in advance.

Answer (a)
The food in container C will turn moldy and rot first followed by A while the food in B will remain unchange. (Food in B will not rot because there is no air supply to it as it is covered by oil)

Answer (b)
Decomposition (covered only in P6) / Rotting needs water and air.

[acforfamily]

Thanks tianzhu and atutor2001, I think that should be the right answer and I wanted to be sure because they did not specify what topic this is under as well.

[Lynn2]

Hello all


Can i check with ks members here over question from : http://www.wendykoh.com/08/primary4-acssa2-science.pdf
Question : 14

Can someone explain to me on the co relation between the three states in relation to room temperature as illustrated in the questions.thank you.

May I just check, question 20,why is the answer not (1),I cant seem to demostrate the 360 rotation movement to my girl...thanks.

Another question, number 13
When syringe with liquid, the nozzle is covered, air compressed and air inside reduced and liquid remained the same.
Whereas for a inflated ball, we draw out 15cm cube of air with a syringe ,why is the air within the ball remain unchange?

Thanks and have a good day all..

cheers
Lynn2

[tianzhu]

Hi

Hope this helps.
[quote]Question : 14
Can someone explain to me on the co relation between the three states in relation to room temperature as illustrated in the questions.[/quote]Are we looking at the same question? There is no mention of relationship to room temperature. Solid A and B have the same mass and volume. Therefore option (1) is correct.
[quote]May I just check, question 20,why is the answer not (1),I cant seem to demostrate the 360 rotation movement to my girl...thanks. [/quote]Shoulders and hips have ball and socket joints. They allow movement in all directions.
How to demonstrate? I wouldn’t suggest any unless you have the flexibility of a gymnast. As for me, my old rusty bones will crack if I attempt to do it.
[quote]Another question, number 13
When syringe with liquid, the nozzle is covered, air compressed and air inside reduced and liquid remained the same.
Whereas for a inflated ball, we draw out 15cm cube of air with a syringe ,why is the air within the ball remain unchange? [/quote]Air has no definite shape and volume. When a gas is placed in a container, it takes the shape of the container that holds it.
In the case of the syringe, when we push the plunger , the air is compressed to take a smaller volume. The volume of water remains the same as water cannot be compressed.
As for the ball, the remaining air spreads out to occupy a bigger space when we draw out a 15 cubic centimetres from it.