Q&A - P4 Science

[jedamum]

Nebbermind:

jedamum:

so Nebbermind same view as Tianzhu? :?

if yes..it is 2 against 2 already.
for me, i dunno. keen to find out. thanks!

Just did a search...Tianzhu has not posted since 1 Oct!!! :yikes:

What happened to our resident tutor??!!!

18days ago only ma...maybe he went on long holiday?

[Nebbermind]

jedamum:

Nebbermind:

[quote=\"jedamum\"] so Nebbermind same view as Tianzhu? :?

if yes..it is 2 against 2 already.
for me, i dunno. keen to find out. thanks!

Just did a search...Tianzhu has not posted since 1 Oct!!! :yikes:

What happened to our resident tutor??!!!

18days ago only ma...maybe he went on long holiday?
:)[/quote]Who approved his holidays??!! Many kids still yet to complete SA2 leh!!!

Must comprain!! :rant:

[verykiasumummy]

Nebbermind:

hi vksmummy


If the ball has a regular shape, I would agree with you.
But if u r familiar with football, when it has less than the required vol of air, ie, 400cm3, it will not be 'perfectly' round. Therefore, the volume cannot be 400cm3.

i stand by my answer... cos that was the conclusion i got from ds's sci teacher... i know as adults, we may not always agree to many sci questions tested in pri syllabus...

in fact, it does not matter if it is a ball or not, whether it was deflated or inflated. pri students only need to know that air can be compressed while at the same time space out to occupy a bigger space. even though the ball may not be round as it is not fully inflated, the volume of air inside is still 400cm3, (same as capacity of ball), even though inly 350cm3 is pumped inside.

[verykiasumummy]

jedamum:

tianzhu:

[quote=\"teh_oh\"]
My child got the Q23 of the same paper incorrect. Do you mind explaining how you/your child get your/her answer, as I am not good at the topic of matter.

Hi

Good Morning.

I think students learned that a gas has no definite volume and that it can be compressed in PSLE science.

Going back to your question, I think the answer lies in the state of the basketball before air is pumped in.

1)If it is in the deflated state, as you pump in more air, the shape of the basketball changes, hence volume increases.

2)If the basketball is already pumped to its recommended pressure, then pumping in more air may not increase its volume. The shape of the ball does not change. You can imagine the ball as similar to a container of fixed volume.

Best wishes

so Nebbermind same view as Tianzhu? :?
if yes..it is 2 against 2 already.
for me, i dunno. keen to find out. thanks![/quote]hi jedamum, was there any previous debate over this that i missed out?

[atutor2001]

verykiasumummy:

..


...in fact, it does not matter if it is a ball or not, whether it was deflated or inflated. pri students only need to know that air can be compressed while at the same time space out to occupy a bigger space. even though the ball may not be round as it is not fully inflated, the volume of air inside is still 400cm3, (same as capacity of ball), even though inly 350cm3 is pumped inside.

If this is a PSLE question, do not interpret it this way. In PSLE, real life practical experience must be applied to interpret all questions.

[jedamum]

verykiasumummy:

jedamum:

[quote=\"tianzhu\"]
Hi

Good Morning.

I think students learned that a gas has no definite volume and that it can be compressed in PSLE science.

Going back to your question, I think the answer lies in the state of the basketball before air is pumped in.

1)If it is in the deflated state, as you pump in more air, the shape of the basketball changes, hence volume increases.

2)If the basketball is already pumped to its recommended pressure, then pumping in more air may not increase its volume. The shape of the ball does not change. You can imagine the ball as similar to a container of fixed volume.

Best wishes

so Nebbermind same view as Tianzhu? :?
if yes..it is 2 against 2 already.
for me, i dunno. keen to find out. thanks!

hi jedamum, was there any previous debate over this that i missed out?[/quote]there was some discussion about matter/pressured air in the earlier pages that i did not read in detail as it was too technical.not sure if it was related to this.

[jedamum]

atutor2001:

verykiasumummy:

..


...in fact, it does not matter if it is a ball or not, whether it was deflated or inflated. pri students only need to know that air can be compressed while at the same time space out to occupy a bigger space. even though the ball may not be round as it is not fully inflated, the volume of air inside is still 400cm3, (same as capacity of ball), even though inly 350cm3 is pumped inside.

If this is a PSLE question, do not interpret it this way. In PSLE, real life practical experience must be applied to interpret all questions.

atutor2001
what is your view on the deflated soccer ball that is not pumped to full capacity? is its volume still 400cm3'?

[atutor2001]

jedamum:

atutor2001
what is your view on the deflated soccer ball that is not pumped to full capacity? is its volume still 400cm3'?

I share the same view that the volume of a deflated ball is less than 400 cm3.

I remembered using the plastic bag as an example when explaining to my children. Each plastic bag has a certain maximum capacity if completely filled with air. However, for a brand new plastic bag (just taken out from its packing), the volume of air inside = 0 cm3.

[verykiasumummy]

there was once this question in my ds1’s paper. 2 containers capacity of 600cm3 attached with an air pump each, container A has 100cm3 more air pumped in, the new volume of air inside is still 600cm3 because air can be compressed.


for container B, 200cm3 of air is pumped out, what is the volume of air in the container and why?

the ans is, still 600cm3, because air can space itself out to occupy the same space of the container because air has no definite volume.

i would apply the same to this question.

[Nebbermind]

Container has fixed shape n volume. Inflatable objects do no have fixed shape or vol UNTIL they reach they final capacity.