2018 PSLE Discussions & Strategies (Born in 2006)

[lee_yl]

[quote=\"mylilgirl\"][quote=\"ryka\"][quote=\"sob7\"][quote=\"lee_yl\"]https://i.postimg.cc/zBsVqFj5/93963_FA5-3_C01-454_A-88_DC-_ECD89514047_D.jpg\">


There was one question that my girl and her friend got different answers. The MCQ question was about three solids X, Y, Z.

Two statements were given:
A. The material making solids X and Y is the same
B. The materials making Y and Z were different

Which of the statement(s) could be concluded from the above experiment?

1). Both A and B
2). B only
3). A only
4). Neither A nor B [/quote

____________________________
B, as Y and Z is definitely different in density given both are solid.
X and Y can be same material or different material, no way to tell with this experiment hence statement is in correct[/quote

___________________________
This question is ambiguous, simple thinking will choose option (2), but as discussed before option (4) also correct for further thinking students since density is a function of mass and volume and there’s NO indication about identical balls or all balls having the same mass.
Is it a trick question or badly set question?[/quote

____________________________
Verified with teacher and tutor who is also current school teacher, the answer is 4. 2 marks deducted for DD.[/quote


___________________________
School teacher and tutor confirmed answer is 4? Can explain why?

Assuming it’s a straight forward experiment (to test materials topic taught in P3):

X = glass,
Y = stone,
Z = styrofoam

Then we can’t say “neither” is correct while answer B still stands true !

And when an experiment is so inconclusive, then it is meaningless to conduct such an experiment, right?

[Usepaper]

sob7:

lee_yl:

https://i.postimg.cc/zBsVqFj5/93963_FA5-3_C01-454_A-88_DC-_ECD89514047_D.jpg\">


There was one question that my girl and her friend got different answers. The MCQ question was about three solids X, Y, Z.

Two statements were given:
A. The material making solids X and Y is the same
B. The materials making Y and Z were different

Which of the statement(s) could be concluded from the above experiment?

1). Both A and B
2). B only
3). A only
4). Neither A nor B

B, as Y and Z is definitely different in density given both are solid.
X and Y can be same material or different material, no way to tell with this experiment hence statement is in correct

https://i.postimg.cc/j5D34rz6/Screenshot_20181004-061327.jpg\">

[pungg]

Usepaper:

sob7:

[quote=\"lee_yl\"]https://i.postimg.cc/zBsVqFj5/93963_FA5-3_C01-454_A-88_DC-_ECD89514047_D.jpg\">


There was one question that my girl and her friend got different answers. The MCQ question was about three solids X, Y, Z.

I
Two statements were given:
A. The material making solids X and Y is the same
B. The materials making Y and Z were different

Which of the statement(s) could be concluded from the above experiment?

1). Both A and B
2). B only
3). A only
4). Neither A nor B

B, as Y and Z is definitely different in density given both are solid.
X and Y can be same material or different material, no way to tell with this experiment hence statement is in correct

https://i.postimg.cc/j5D34rz6/Screenshot_20181004-061327.jpg\">[/quote]In their syllabus they didn't learn about Density. According to syllabus either float or sink,
So, more possible answer B

[Usepaper]

I would think the answer is B also. They don’t even know the density formula. Plus it is the material and the size of the object that matter…not the weight. So the 3 objects are drawn in the same size and the only difference that makes it sink and float is the material.

[Bubbly Ang]

Yes I would think is B too. Bcox density is not in their syllabus. All drawn to the same size and they say is solid object, so means no hollow (no trap air). Just that I feel this qn is not clear enough. They should state that identical size and mass, etc.

[ryka]

What I can conclude from the 3 solid (solid = state of matters) balls questions, all parents seem to agree that this is the most ambiguous question in this year PSLE


Both answers are correct from the limited information given by the questions. It is not fair if answer (2) marked wrong since P6 students syllabus does not cover density concept in depth. It is also not fair if answer (4) marked wrong since it mean some P6 students with extra (correct) knowledge being penalized of knowing deeper density concepts.

It will be interesting to find out how school teachers going to explain this question to next year PSLE students.

[Iluvmygals]

While the formula for density is mass/volume, it doesn’t mean that a same material will have varying density because of different volume or different mass. So, a big iron ball will have the same density as a small iron ball, even though they have different volume. The density of a material will only change when pressure or temperature changed.


So since the 3 balls existed in the same temperature and pressure, the floating ball will be a different material from the balls that sank. We don’t need to know the mass and volume of the balls to conclude that they are of different density, and hence different material.

[jj_1808]

My son told me that the answer is B.

[pungg]

Regarding the pollination question

They didnt mention anything about pistil and stamen, so based on the diagram why can’t be possible by insect one flower?

[ryka]

Iluvmygals:

While the formula for density is mass/volume, it doesn't mean that a same material will have varying density because of different volume or different mass. So, a big iron ball will have the same density as a small iron ball, even though they have different volume. The density of a material will only change when pressure or temperature changed.


So since the 3 balls existed in the same temperature and pressure, the floating ball will be a different material from the balls that sank. We don't need to know the mass and volume of the balls to conclude that they are of different density, and hence different material.

The questions showed 3 similar size balls (conclude as similar volume), the unknown / no information is the mass. Hence, there is possibility that 2 balls of the same material, one being solid and another one hollow will result in one sink (solid) and the other one floating (hollow).