Q&A - P3 Science

[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.

[kitty2]

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.

I agreed with this answer,when a magnet is hung freely and come to rest will always point in a North South direction.

[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.