Q&A - PSLE Science

[atutor2001]

Misconception on graph plotting :


Many think that :
\"For every value of x coordinate (e.g. number of batteries) there can only be one value for the y coordinate (e.g. brightness)\"

No, there is no such restriction - for each x coordinate, there can be more than 1 value for the y coordinate.

For example, if the bulb becomes very bright then fused at the 6th battery, there will be 2 values of y (brightness) for the \"6th battery\".

The 1st value is the maximum brightness and the 2nd value is zero brightness. Since the maximum brightness occurred first, the graph from the coordinates of the 5th battery will be joined to the point of maximum brightness then vertically downwards to the zero brightness, then to the 7th battery along the zero line.

[atutor2001]

jesschan:

Thanks atutor and nebbermind for the comments. Just wondering if the x-axis is time or voltage, will there will any difference in the answer?

When a bulb fused, the action is immediate / instantaneous i.e. a drop from maximum brightness to zero in almost zero duration or voltage change. Therefore, the answer should not be any different if the x-axis is changed to voltage or time.

[jesschan]

Thanks, atutor. So do u also agree that the bulb could have fused at the 6th battery?

[Nebbermind]

atutor2001:

Misconception on graph plotting :


Many think that :
\"For every value of x coordinate (e.g. number of batteries) there can only be one value for the y coordinate (e.g. brightness)\"

No, there is no such restriction - for each x coordinate, there can be more than 1 value for the y coordinate.

For example, if the bulb becomes very bright then fused at the 6th battery, there will be 2 values of y (brightness) for the \"6th battery\".

The 1st value is the maximum brightness and the 2nd value is zero brightness. Since the maximum brightness occurred first, the graph from the coordinates of the 5th battery will be joined to the point of maximum brightness then vertically downwards to the zero brightness, then to the 7th battery along the zero line.

thank you for sharing.

however, I still maintain that for the simplicity of such experiment, only one reading is taken for each +/- of battery, and should usually be taken at the 'steady state'. Should the bulb fused at the 6th battery, then the result would be '0' since it's brightness is only momental. Also note, x-axis is for 'brightness' and not 'max brightness'.

anyway, if I'm the parent, I'll put my case across to the teacher this way, unless someone is able to convince me otherwise.

[atutor2001]

jesschan:

Thanks, atutor. So do u also agree that the bulb could have fused at the 6th battery?

No the graph does not indicate so. If it did fuse at the 6th battery, the brightness must first drop to zero at the 6th battery. The point where zero brightness first occurred indicates the point where the bulb fused.

The comments from wkong's sch teacher are the most accurate. If the brightness is monitored and plotted graphically by a machine, the brightness will increase in \"steps\" each time a battery is added. At the \"battery\" where it fused, there would be a \"spike\" in the brightness before dropping to zero

[andante]

Does anyone have catholic high P6 science SA1 as I bought whole lot but there is only prelim and no SA1 ?

[jesschan]

Thanks to everyone for your input. Guess I can only conclude that this is a bad question…

[tisha]

andante:

Does anyone have catholic high P6 science SA1 as I bought whole lot but there is only prelim and no SA1 ?

Check this:
http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA1-CHS.pdf

In our bundle it was under SA1, but when I checked carefully it is of Prelim1. Probably in CHS they refer to SA1 for P6 as prelim1. Under SA2 set there is Prelim2.

[andante]

tisha:

andante:

Does anyone have catholic high P6 science SA1 as I bought whole lot but there is only prelim and no SA1 ?

Check this:
http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA1-CHS.pdf

In our bundle it was under SA1, but when I checked carefully it is of Prelim1. Probably in CHS they refer to SA1 for P6 as prelim1. Under SA2 set there is Prelim2.

Thank you very much.

[anneshirleygilbert]

Need some help on P5 question :


Living things reproduce to ______________
A)\tProvide food for other living things
B)\tLearn how to take care of their young
C)\tPass on their characteristics to their young
D)\tEnsure that their species do not become extinct

(1)\t A only
(2)\t D only
(3)\t B and C
(4)\t C and D

The answer given is (4), but I think it should be (2).

Statement D states the purpose of reproduction, whereas Statement C is the natural by-product of Statement D. In other words, the purpose of reproduction is to ensure that their species do not become extinct. In reproducing, i.e. having offspring, living things do pass on their characteristics to their young.

I’ve just re-read the PSLE Revision Guide by Marshall Cavendish – it states the purpose of reproduction is to ensure the survival and continuity of their own kind.

Am I wrong? Am I being hair-splittingly exacting? or should I put this question under the list of "badly crafted questions"?

Please help.