Q&A - P3 Science

[atutor2001]

teh_oh:

My queries:-

1) can the above plant absorb water without roots? (Answer Key: R and S)
2) is this under Diversity or Systems topic?

1) Plant can absorb water without roots. The water enters the xylem (water carrying tubes) in the stem because of (a) capillary action (b) transpiration. Capillary action is the attraction of water molecule to the cells in the xylem and pulling the water upwards. Transpiration is the evaporation of water through the stomata, and water moving up to fill the empty space on top.
Personally I feel that P & Q should also be correct answer because the amount of roots in both pictures are the same i.e. only 1 variable is changed (which is the number of leaves) and it is therefore a fair test. I guess R & S are better options because the set-ups eliminate any possibility of errors caused by the presence of roots.

2) I think this question is on experimental method & systems

[teh_oh]

atutor2001:

teh_oh:

My queries:

1) Is mould a micro-organism? (Answer Key: 3)
2) How do bacterium reproduce?

1) Yes, mould is micro-organism. We cannot see micro-organism with our naked eyes but yet we can see mould. That is because what we saw are thousands of mould grouped together. We will not be able to see it if it is a single mould.

2) Bacteria reproduces by cell division. Mould is a fungi and it reproduces by spores.

Hi atutor2001,

Thank you for the clarifications.
Two more thing, is mould then also a type of fungi?
And, do bacteria feed the same way as fungi? That is they feed on other dead or living organism by breaking them down and absorbing them.

Thanks again.

[teh_oh]

atutor2001:

teh_oh:

My queries:-

1) can the above plant absorb water without roots? (Answer Key: R and S)
2) is this under Diversity or Systems topic?

1) Plant can absorb water without roots. The water enters the xylem (water carrying tubes) in the stem because of (a) capillary action (b) transpiration. Capillary action is the attraction of water molecule to the cells in the xylem and pulling the water upwards. Transpiration is the evaporation of water through the stomata, and water moving up to fill the empty space on top.
Personally I feel that P & Q should also be correct answer because the amount of roots in both pictures are the same i.e. only 1 variable is changed (which is the number of leaves) and it is therefore a fair test. I guess R & S are better options because the set-ups eliminate any possibility of errors caused by the presence of roots.

2) I think this question is on experimental method & systems

Hi atutor2001,

Thank you.

[atutor2001]

teh_oh:

Two more thing, is mould then also a type of fungi?
And, do bacteria feed the same way as fungi? That is they feed on other dead or living organism by breaking them down and absorbing them.

Yes, mould is a fungi and they feed on other dead or living organism by breaking them down into simple substances (not absorbing them). Most of these simple substances are returned to the ground as nutrient for plants and some are released as gases to the surrounding air.

[Nebbermind]

Need advice on magnetic prop of Stainless Steel.


From what I was told, different grades of S/Steel will have different magnetic prop. So what is taught in schools, or rather what is the accepted ‘answer’ for PSLE?

[corneyAmber]

Champion:

ksi:

For polar bear and fox, do you use fur or hair for their outer covering? (i.e. acceptable to marking scheme)


Or are they use synonymously and both accepted in marking?

Ah Po! I think both are acceptable - according to the Ultimate Science Guide (Lower Block)
http://i56.tinypic.com/28kk708.jpg\">

Thanks Champ!! Alot of fine prints to read...

[atutor2001]

Nebbermind:

Need advice on magnetic prop of Stainless Steel.


From what I was told, different grades of S/Steel will have different magnetic prop. So what is taught in schools, or rather what is the accepted 'answer' for PSLE?

Wow! you have brought out a very scary exception to the property of steel.

To-date, I have not come across any question on magnetic property of stainless steel. So far, Pr Science has limited the list of magnetic material to iron, steel, cobalt, nickel and carbon. Lets pray that no adventurous teacher will bring in \"stainless steel\" for question on magnetism. Otherwise, it will bring more confusion, similar to question like whether \"does shark lay eggs or give birth to young alive\" - students who read science journals will know that the answer is \"not possible to tell\", depending on the species. So the answer on magnetic property of stainless steel will again be \"not possible to tell\", depending on the grade of the stainless steel.

[Nebbermind]

atutor2001:

Wow! you have brought out a very scary exception to the property of steel.


To-date, I have not come across any question on magnetic property of stainless steel. So far, Pr Science has limited the list of magnetic material to iron, steel, cobalt, nickel and carbon. Lets pray that no adventurous teacher will bring in \"stainless steel\" for question on magnetism. Otherwise, it will bring more confusion, similar to question like whether \"does shark lay eggs or give birth to young alive\" - students who read science journals will know that the answer is \"not possible to tell\", depending on the species. So the answer on magnetic property of stainless steel will again be \"not possible to tell\", depending on the grade of the stainless steel.

Just came across in some worksheet. Think it's a qn on separating diff metals using magnet and S/Steel is classified as 'magnetic'.

[atutor2001]

Nebbermind:

atutor2001:

Wow! you have brought out a very scary exception to the property of steel.


To-date, I have not come across any question on magnetic property of stainless steel. So far, Pr Science has limited the list of magnetic material to iron, steel, cobalt, nickel and carbon. Lets pray that no adventurous teacher will bring in \"stainless steel\" for question on magnetism. Otherwise, it will bring more confusion, similar to question like whether \"does shark lay eggs or give birth to young alive\" - students who read science journals will know that the answer is \"not possible to tell\", depending on the species. So the answer on magnetic property of stainless steel will again be \"not possible to tell\", depending on the grade of the stainless steel.

Just came across in some worksheet. Think it's a qn on separating diff metals using magnet and S/Steel is classified as 'magnetic'.

Oh dear! A new evil has been created. The \"shark\" question was around some 10 over years ago. There was no \"stainless steel magnetism\" problem then. Hope that this worksheet is not a past year school question but just a question from assessment books. Otherwise I really wish that MOE has a permanent rep. in this forum to address all these \"not possible to tell\" issue.

PS
Just remembered one more nightmare which often surfaces in school paper. The question is \"Is pollen grain single cell.\" I was surprised to find the schools' answer to be yes. Actually pollen grain has at least 2 cells. Otherwise how to grow pollen tube and then fertilise the ovum.

[Just4Fun]

Q fr Lower Block Science by Janet Sim :

Which of the following statesments about our teethn are true ?
a, Our teeth cut and grind the food we eat into simple substances that can be absorbed by our body .
b, Our teeth produce digestive juices to break down food
c, we hv a max of 32 permanent teeth
d, we hv 2 sets of teeth in our life.

Ans is C & d only.

Why (a) is not true ? Anyone can help to explain ?
Thx so much !