Q&A - PSLE Science

[bobsg01]

P6 Science


How to explain the sunset that Annie is at position 2 (which is the ans)? :scratchhead:

Thanks in advance.

http://i56.tinypic.com/2eo8so5.jpg\">

[tianzhu]

Hi bobsg01


I think, effective 2010, the Solar System is no longer in the PSLE Science syllabus.Please confirm it with your school teacher. It’s good news for the Solar System is not an easy topic to grasp for many PSLE students.

The Earth rotates on an imaginary axis from West to East. It takes about 24 hours or 1 day to complete one rotation.

At any one time, only one side of the Earth is facing the Sun. The side facing the Sun will experience daytime. The side that faces away from the Sun will experience night time. Hence, the Earth’s rotation gives us day and night.

Position 2 is a logical answer. Annie is experiencing sunset now because as the Earth rotates, the side facing the Sun will be rotated away from the Sun.

Best wishes

[bobsg01]

Thanks tianzhu, will definately check.

http://i56.tinypic.com/i4itdf.gif\">

[P5G]

Please help.


Question 10.
Simon completely filled two identical syringes, one with air while the other with water, and covered them with black paper as shown in the diagram attached.
http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA2-ACS.pdf

He then pushed each plunger as hard as he could and measured the distance, x.
Which one if the following shows the correct values of x?

Syringe with water (x / cm) /// Syringe with air (x / cm)
(1) 10 /// 0
(2) 0 /// 10
(3) 10 /// 7
(4) 7 /// 10


Question 40a.

The answer given uses 'plant without roots' for the control set-up.
Should the 'plant without leaves' be used for the control set-up instead?

Please advise.

TIA.
Is the answer given (1) correct?

[P5G]

Please help.


http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA2-CHS.pdf


Should the answer for question 9 be (4) instead of (2) as given?

Please advise how to get the answers for questions 14, 17, 23 and 27.


TIA.

[tianzhu]

bobsg01:

Thanks tianzhu, will definately check.

Hi

You're welcome.

Best wishes

[tianzhu]

Hi P5G


For Q10, a student needs to have knowledge of “The Three States of Matter”.

A liquid like water has a fixed volume, it cannot be compressed.

Air has no fixed volume, it can be compressed.

Hence option (1) is correct.

For Q40a, I agree with your answer of picking the plant without leaves as the control unit.

In this experiment, Jeremy wanted to find out if the leaves can give out water vapour. Plants release water to the surroundings through a process called transpiration.

The leaves are removed from plant in the control unit so that we can compare what happens with live leaves to what happens with no leaves. This enables us to conclude that the water droplets on the inner surface of the plastic bag in set up Y come from the leaves.

Best wishes

[Nebbermind]

TZ


I thought it shd be (3) for water vs air…donch think air shd e ‘0’.

[tianzhu]

Nebbermind:

TZ


I thought it shd be (3) for water vs air...donch think air shd e '0'.

Hi

The markings on the sliding indicator show the distance travelled by the plunger of the syringe. I think there is still small space at the tip of the syringe when the plunger reaches zero.

When one press as hard as possible, it’s possible to reach the zero mark.

Watch this video and observe the position of the plunger when the guy applies force.

http://www.blinkx.com/watch-video/the-fire-syringe/GOZmVBYHqBNU8khxc2Ug3g

Best wishes

[ivanhoo99]

Why do we sweat?

I need a full proper answer…
Thank you