Q&A - PSLE Science

[tianzhu]

elkniwt:

Hi,


Referring to Q24 of this paper http://www.orlesson.org/orp/09Sc/2009-Sc-CA1-MahaBodhi.pdf

Need some help to understand why the answer is (3) A and C only [I thought it is (4) cos if evaporation has taken place, then there will a reduction in volume as well as a reduction in weight.] Some advices please. Thanks!

Hi

In primary science, students learned about the three states of water. They are solid(ice),liquid(water) and gas (steam or water vapour).

In this question, substance X is not labelled. Students who are familiar with States of Matter should be able to see that there is a change of state from solid to liquid. Naturally, the change from ice to water may come to mind as this is probably the only example in their primary science textbook (as far as I can remember while going through my boy’s book last year).

You have correctly pointed out that there will be evaporation. However, the key point is here is what you observe after two hours. Undeniably, the liquid evaporates, but the amount may be insignificantly or too negligible for us to see noticeable changes in weight.Hence option (3) is a logical answer based on the context in the question.

However if the question states that the set up is left overnight, I’d venture to say that there will be change of weight as the amount of water evaporated may be significant enough to influence the weight.

Best wishes

[tianzhu]

elkniwt:

Any possibility for the bigger object to be a square-base prism, then top view you will still see a big square and a small square but side view will show a triangle and a square ??? (Just throwing in my thoughts) :?

Hi

Throwing up thoughts is good way to explore science. It opens up a window of possibilities for us to see this interesting world.

Those without experiences in technical drawing may find it a bit difficult to understand this question.

The question shows the top view of two square cubes of different sizes. In orthographic projection, it is called the plan view. I think students will learn more about drawing in Design and Technology in secondary one.

At this juncture, just take this. To represent a triangular prism, you need to draw a dividing line in the bigger square. Imagine dividing the bigger square in the question into two similar rectangles. I suggest you find a triangular object in your house as it’ll help you to have a better picture.

If you still need further clarification, let me know. I’ll try to draw a sketch at a later time if you need one.

Best wishes

[elkniwt]

Dear tianzhu,


Thank you very much for your help and clarification. I need to "digest" a bit before I can explain to my dd.

[tianzhu]

elkniwt:

Thank you very much for your help and clarification. I need to \"digest\" a bit before I can explain to my dd.

Hi elkniwt

Good Morning
You’re welcome.

If you need the drawing for the NY question, Q30, just let me know.

Best wishes

[tianzhu]

Hi


This is a very interesting question,Q41NY SA2 2009.
http://www.orlesson.org/orp/09Sc/2009-P6-Science-SA2-Nanyang.pdf

This video may help you to understand it better.
http://www.youtube.com/watch?v=6sIB2kL-BWc&feature=related

Best wishes

[Brenda10]

tianzhu:

Hi


This is a very interesting question,Q41NY SA2 2009.
http://www.orlesson.org/orp/09Sc/2009-P6-Science-SA2-Nanyang.pdf

This video may help you to understand it better.
http://www.youtube.com/watch?v=6sIB2kL-BWc&feature=related

Best wishes

Hi Tianzhu

Thank you for sharing.

DD said to separate the two books,just hold the side of one of the books and shake the book lightly.The two books would separate by themselves.
I then realized that she had encountered it before because she saw us shuffling the poker cards during Chinese New Year :oops: and out of curiously she also tried to do it with two books and thus discovered how to seperate two books.

[tianzhu]

Hi Brenda10


Enjoy the science journey with your girl.

Best wishes

[tianzhu]

Hi


Gulf of Mexico Oil Spill 2010 – Effects on Fish and Wildlife
http://apexnewsnetwork.com/23051/gulf-of-mexico-oil-spill-2010-effects-on-fish-and-wildlife/

How oil spills affect birds and marine animals is commonly tested in primary science. One such question is Q36 from PLMGPS SA2 2009. (pg 39)
http://www.orlesson.org/orp/09Sc/2009-P6-Science-SA2-PLMGS.pdf

You may learn more about the impacts of oil spills on birds by following these links.
http://www.youtube.com/watch?v=Z0nmgjsPyL4&feature=related
http://www.youtube.com/watch?v=z_ZAWU_Jxug&feature=related

Best wishes

[P5G]

Please help.



Q15.

http://www.orlesson.org/orp/09Sc/2009-Sc-CA2-Nanyang.pdf


My answer is 2 since it does not mention that the experiement is repeated with more or less strokes.

But worksheet answer is 4.


Please advise which answer is correct.


TIA.

[Muffins]

Hi P5G, the answer is more inclined towards 4, as it did not specifically mention that the strokes he used increased or decreased, he jusat stroked it once and used the magnetised nail....