Q&A - PSLE Science

[tianzhu]

Tang:

Hi,

Here are some terms:

Heat flows, heat travels

Heat gains, heat loss

temperature

good conductor of heat / poor conductor of heat

slows down heat loss / slows down heat gain

hot region / cold region

melting point / freezing point

boiling point

solid / liquid / gas

gains heat and expands

loses heat and contracts

.......

Hi Tang

Thank you for your response.
I am sure future PSLE students will appreciate it.

Best wishes

[tianzhu]

Hi


According to OMY, this advanced technology toilet bowl system is found at the public toilet in Raffles City S.C
http://fun.omy.sg/common/media/popup/?code=section%3Dcj%26artID%3D18625%26type%3Dimage%26&section=cj&artID=18625&type=image

They are commonly found in airports, hotels, etc in Japan.

If are keen to find out the science behind the toilet bowl, you may google for more information.

How about thinking of some related PSLE Science questions?

Best wishes

[youngtay]

Hi, please help


Which statement about the circulatory system is correct?

1) It consists of the nose, windpipe and lungs.
2) It carries water to different parts of the body.
3) It digests food and passes it to the blood.
4) It removes carbon dioxide from our body.

TIA

[tianzhu]

youngtay:

Hi, please help


Which statement about the circulatory system is correct?

1) It consists of the nose, windpipe and lungs.
2) It carries water to different parts of the body.
3) It digests food and passes it to the blood.
4) It removes carbon dioxide from our body.

TIA

Hi

In PSLE Science, students learned that the blood transports digested food, oxygen, water, carbon dioxide and other waste materials to different parts of the body.

Option(1) and (3) are out.

Carbon dioxide is transported from the heart to the lungs to be breathed out or removed from the body. This rules out option(4).

I'd like to go for option (2).

Best wishes

[Vanilla Cake]

Compare the following differences between the respiratory and circulatory system in plants and in human beings. Which of them is wrong?


Option 1
Plant: Exchange of gases takes place in the leaves
Human: Exchange of gases takes place in the lungs

Option 2
Plant: Oxygen is pumped to all parts of the plant
Human: Oxygen is pumped to all parts of the body

Option 3
Plant: Carbon dioxide is not returned to leaves
Human: Carbon dioxide is returned to the lungs.

Option 4
Plant: There is no blood to carry food around the plant
Human: Blood carries food around the body

Answer given is option (2).
Is this correct?
Option (1) and option (4) are obviously correct.
Pls help to explain why option (2) is chosen instead of option (3) for this question.
TIA for your time and effort.

[tianzhu]

Vanilla Cake:

Compare the following differences between the respiratory and circulatory system in plants and in human beings. Which of them is wrong?

Hi VC

The question asks which of them is wrong.

Option 2 is correct.

The plant does not have a pumping device similar to the heart.

Best wishes

[Vanilla Cake]

tianzhu:

Hi VC


The question asks which of them is wrong.

Option 2 is correct.

The plant does not have a pumping device similar to the heart.

Best wishes

Hi Uncle tianzhu,

Thks for your explanation and super fast response.
Here's another one - Q32 from the same paper.
There are 2 diagrams for this question and I will try my best to describe them.

Q32
Albert noticed that a \"cloud\" formed near the spout of a kettle of water when the water boiled.

Diagram 1 showing a kettle with a spout and \"cloud\" coming out from it. The \"cloud\" is drawn near to the spout.

(a) What actually made up the \"cloud\"? (1 mark)
No problem for part (a). Answer is \"tiny water droplets\".

Albert also noticed that the \"cloud\" moved higher and higher as the water continued to boil.

Diagram 2 showing the same kettle with the \"cloud\" is drawn is such a way that it appears to \"grow\" larger and rising upwards.

(b) Why did the \"cloud\" move higher and higher? (2 marls)

Answer given: The air above the spout got warmer and so condensation would like place higher where it was cooler.

Is the answer given correct? Could you pls help to answer part (b) of this question? TIA for your time and effort. Much appreciated.

[starlight1968sg]

Vanilla Cake:

(b) Why did the \"cloud\" move higher and higher? (2 marls)


Answer given: The air above the spout got warmer and so condensation would like place higher where it was cooler.

Is the answer given correct? Could you pls help to answer part (b) of this question? TIA for your time and effort. Much appreciated.

Didnt expect this ans but think of it, quite true as the hot air right from the spout pushes the \"cloud\" higher.

[tianzhu]

Hi VC


The answer from the WS is a logical one.

Best wishes

[tianzhu]

Watermist Gun


The gun works by spraying the water out into a fine mist instead of spurting a jet of water as a conventional hose does.

http://www.youtube.com/watch?v=24PdBM-phVQ

How are water mists more effective than conventional water jets in fighting fire?

Give it some thoughts using concepts within PSLE Science syllabus.

Best wishes