Q&A - P3 Science

[Sun_2010]

cimman:

tianzhu:

[quote=\"shirley.tamzil\"]Need help with the below question:


Which of the following statements about heat is correct?
1. Heat travels in a straight line.
2. A thermometer is used to measure the amount of heat of an object.
3. When one object is placed on top of another, the object on top will gain heat because heat rises.
4. At the same temperature, a dark colored object will give out more heat than a light colored object.

Hi

I am more inclined to go for option (4).

If you go through the concepts of heat learned in lower primary science, you’ll realise that options 1 to 3 are offside. Going through the process of elimination, you’re left with option (4).

Dull black surfaces are better emitters of infrared radiation than shiny white surface.

Take for example, in a thermos flask, the wall of the glass are silvered to reflect the radiant heat back to the hot liquid so as to minimise heat loss through radiation.

I am not too sure if radiation is covered in the primary science syllabus, but you should be able to learn more about it from secondary science textbooks.

Best wishes

I would say (3) because there is transfer of heat via conduction (top object touches bottom object), something a primary school student should be familiar with. Radiated heat would not be something they're familiar with at this point in time. So between a concept that they have learnt and something that they will only learn in Secondary school, (3) seems most approriate.[/quote]I think option 3 is about heat rising up that is not conduction.

As we know even if the hot object is placed up and cold object is below, the cold object below will gain heat because of conduction. In this case heat does not rise up but travels below.

So my answer would be 4.

[shirley.020816tamzil]

shirley.tamzil:

Need help with the below question:


Which of the following statements about heat is correct?
1. Heat travels in a straight line.
2. A thermometer is used to measure the amount of heat of an object.
3. When one object is placed on top of another, the object on top will gain heat because heat rises.
4. At the same temperature, a dark colored object will give out more heat than a light colored object.

The answer given was 4, but I have difficulties explaining why to my P4 DS. Other than eliminating the incorrect answer, can't explain the correct answer.

[atutor2001]

black object absorbs heat faster and also lose heat faster.


many confuse heat with light.

this is not in pr syllabus but always appear in sch questions

[teh_oh]

Hi,

Need some clarifications…
1) What are found on the underside of the leaves of ferns?
Spores or Spore cases?

2) Are there such things as ‘spore bags’?

[atutor2001]

Spore cases containing spores are found on the underside of fern leaves.


If it is mcq, I will pick spores over spore cases (then complain to the teacher :lol: )

[teh_oh]

atutor2001:

Spore cases containing spores are found on the underside of fern leaves.


If it is mcq, I will pick spores over spore cases.

Hi atutor2001,
Thanks. Are there such things as spore bags?
My child wrote in his school science exercise book that spores are contained in spore bags. In his textbook, it wrote spores in breadmould are in spore cases. In an MCQ question where there is an option of spore bags and spore cases, the choice of spore cases is correct. I read one guide book, while it wrote that breadmould spores are contained in spore cases, there is a small picture and at the annotation under the gills of fungus, it state spore bags.
I'm confused.

[atutor2001]

I have not come across the term spore bags which is why I did not attempt to answer your query.


Could it be a case of the teacher explaining that spore cases are like bags that results in the term "spore bags" being found in the exercise book? Nevertheless, I would stick to spore cases.

Cheers

[teh_oh]

atutor2001:

I have not come across the term spore bags which is why I did not attempt to answer your query.


Could it be a case of the teacher explaining that spore cases are like bags that results in the term \"spore bags\" being found in the exercise book? Nevertheless, I would stick to spore cases.

Cheers

Hi atutor2001,
:thankyou:

[usaik]

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Hi, I appreciate kind advice on what should be the correct answer to the above. I do not have the answer key but know that (2) is wrong.

[tianzhu]

Hi


When water is heated to 100 degrees C, it boils.

During boiling, water changes from a liquid to a hot gas called steam which is invisible.

The white clouds or mist are actually tiny water droplets floating in the air. These are formed when steam loses heat to the surrounding air and changes back into water as it cools. The change of state of steam from gas to a liquid is called condensation.

I’d go for steam and water droplets

Best wishes