Q&A - PSLE Science

[Verysuperkiasu]

tianzhu:

Verysuperkiasu:

So....we can still the word 'compress' for the stress ball? Coz it kind of contradicts the property of solid - can't be compressed.

Hi

You’ve brought up a good point, the word 'compress' for the stress ball may be inappropriate.

We are given the understanding from smartmummy’s post that this question if from a P3/P4 assessment book.

I am not sure if smartmummy has summarised the question from the book. If she did, the question may not appear as it is in its original form.

I think many P3 students are not familiar with stress ball, as such I believe there should be a picture or image of a stress ball together with a brief description of the material used to make the ball in the question.

A point to note is that the answer stresses those tiny air spaces inside the foam rubber can be compressed when the ball is squeezed.It’s the air spaces which can be compressed not the stress ball.

It’ll be helpful if smartmummy could post the original question, if possible. Perhaps, the term squeeze may be more suitable.

The concept on why \"sponge is a solid\" is applicable to this question.

Best wishes

Thanks Tianzhu for the clarification. I've never thought of referring the word 'compressed' to the air within the air spaces .... that was brilliant!

[atutor2001]

Hi Chrisu


For question 11, the correct answer is 4. The key words in the questions is "will continue to grow". At stage B and C, the seedling can still continue to grow without sunlight as there are food from the seed leaves. At stage D, the correct picture should show shrunken seed leaves but unfortunately they did not show it as such. So if we are very fuzzy, and follow strictly to the picture given, there is no answer.

For question 20, if we follow strictly to the proportion of the cup in the picture, the answers are B and C. If just based on shape alone, I agree with you that B, C, D, E are answers.

D is not acceptable because the curve on top is "rounder" than the curve below. Their curvature should be the same.

E is not acceptable because it is too elongated. Proportion-wise, the shadow cannot be so long.

Conclusion : none of the options is correct.

[Nebbermind]

atutor2001:

Hi Chrisu


For question 11, the correct answer is 4. The key words in the questions is \"will continue to grow\". At stage B and C, the seedling can still continue to grow without sunlight as there are food from the seed leaves. At stage D, the correct picture should show shrunken seed leaves but unfortunately they did not show it as such. So if we are very fuzzy, and follow strictly to the picture given, there is no answer.

For question 20, if we follow strictly to the proportion of the cup in the picture, the answers are B and C. If just based on shape alone, I agree with you that B, C, D, E are answers.

D is not acceptable because the curve on top is \"rounder\" than the curve below. Their curvature should be the same.

E is not acceptable because it is too elongated. Proportion-wise, the shadow cannot be so long.

Conclusion : none of the options is correct.

For Q11, agree that they shd show shriveled seed leaves to remove any doubt on the answer.

For Q20, E is quite impossible to achieve. D not so sure. B & C quite clear cut possible.

[chrisu]

I've just done some shadow play by myself so the shadow is not so perfect. But if there is a more powerful torch and one more person to assist, it should be perfect.


Shadow C can be achieved if the torch is shine directly to achieve a more squarish shape;
http://img.photobucket.com/albums/v160/guppiesonli/Misc/Shadow-C.jpg\">

Shadow D can be achieved by shining the torch from bottom up so that the top is more rounder than the bottom. You can adjust it accordingly to achieve the required shape with 2 person;
http://img.photobucket.com/albums/v160/guppiesonli/Misc/Shadow-D.jpg\">

For Shadow E, I shine the torch from top to bottom of mug and further away from the mug. The shadow will be slimmer and looks elongated. In shadow play, it may not be proportional depending on the distance of source to object;
http://img.photobucket.com/albums/v160/guppiesonli/Misc/Shadow-E.jpg\">

So I still think B,C, D and E is the correct shadows and none of the given answers is correct.

atutor2001:

Hi Chrisu

For question 11, the correct answer is 4. The key words in the questions is \"will continue to grow\". At stage B and C, the seedling can still continue to grow without sunlight as there are food from the seed leaves. At stage D, the correct picture should show shrunken seed leaves but unfortunately they did not show it as such. So if we are very fuzzy, and follow strictly to the picture given, there is no answer.

For question 20, if we follow strictly to the proportion of the cup in the picture, the answers are B and C. If just based on shape alone, I agree with you that B, C, D, E are answers.

D is not acceptable because the curve on top is \"rounder\" than the curve below. Their curvature should be the same.

E is not acceptable because it is too elongated. Proportion-wise, the shadow cannot be so long.

Conclusion : none of the options is correct.

[Nebbermind]

For E, have u tried positioning the handle such that it will not cast any shadow?

[Tang]

chrisu:

Here is another question from http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA2-CombinedSch.pdf.


The given answer is (3).

My daughter's answer is (4) as in (3), the food is still provided by the cotyledon though the first true leaf already appeared.

Also in some science text, once the hypocotyl arch emerges from the soil, sunlight is required to trigger its growth - thus (2) may also be correct.

Confusing...so what is acceptable in PSLE standard answer?

Hi,

The answers given are different from those that my sister had (from the papers which she bought from the vendor end of last year).

Answers given for Questions 9, 11, 16 and 20 are 1, 4, 4 and 4 respectively.

[chrisu]

yes, it's possible and the handle shadow cannot be seen. Just position the handle behind. Of course need to tilt a bit only.

Nebbermind:

For E, have u tried positioning the handle such that it will not cast any shadow?

[Nebbermind]

chrisu:

yes, it's possible and the handle shadow cannot be seen. Just position the handle behind. Of course need to tilt a bit only.

Nebbermind:

For E, have u tried positioning the handle such that it will not cast any shadow?

when tilted only a bit, the shadow is more like D. I can't get anything near E as the handle's shadow will appear. anything, just for discussion only, not fault finding.

[atutor2001]

Hi Chrisu


Thank you for producing shadow D. It is my mistake to assume that the light source is along the central-line of the cup, which will then produce symmetrical curves. You are the best parent any child can find.

[pixiedust]

Yes, thank you Chrisu! You are the BEST :rahrah:

Thank you for being persistent with this.

I re-tested with help from my dh - the non-sharp edges are due to the 'diffused' light source from the torch. We remove the glass covering so there is a single light source.

Here are our shadows :
http://i1197.photobucket.com/albums/aa424/pixie_dust8/image_c.jpg\">
http://i1197.photobucket.com/albums/aa424/pixie_dust8/imagee.jpg\">

Conclusion: Agree with you shadows B,C,D,E can be formed.
With input from Tang, answer for Q20 should be (4) but it is still incorrect as E is not included.