Q&A - PSLE Science

[tianzhu]

Joy:

I read with great interest in this psle sci topic...


Just wonder, many a time, when we guide our child to do application questions on sci, its the concept or application skill that our child really need to have?

Hi

I think scientific concepts and application skills are closely intertwined, just like husband and wife. The home’s peace and harmony is inextricably intertwined with the integration of the family members living closely together.

With the demands of the newer trend of Higher Order thinking questions, it is no longer enough to know or memorise facts.To do well in Science, you need to be able applying concepts to a new situation and give relevant answers that connect to the situation in the question. It is not an easy skill to be taught to a 12 years old kid.

I find the briefing session for parents in St Anthony’s Primary School ( http://anthonian.edu.sg/)
useful. Hope you’ll also find it meaningful.

[James Ang]

turquoise:

tianzhu:

Hi

Thank you for your responses.

Q1) Organism A is most commonly found in leaf litter and rotting log community. Which one of the following organisms is Organism A most likely to be?

1) Earthworm
2) Ant
3) Grass
4) Bracket Fungus

The answer given in the WS is (4).

Which of the following organisms can reproduce by asexual reproduction?
E. Amoeba
F. Yeast
G. Earthworm
H. Bacterium

(1) E and F only
(2) E and H only
(3) E, F and H only
(4) All the above

The answer given in the WS is (4).

Hi tianzhu,

Which worksheet is this and how reliable are the answers given?

I can understand the ambiguity in the second question because some earthworms can reproduce asexually but my dd's teacher says the answer should not include earthworms at the PSLE level.

As for the first question, I really question if the correct answer should be bracket fungus.

Perhaps someone can enlighten us as to the correct answers.

Q1 is testing whether the student understand the decomposers are found in leaf litter and rotting log communities. So the only decomposer is the bracket fungus.

The earthworm reproduces asexually is a fact commonly found in the guides.

Actually it is very difficult to set \"perfect\" science questions because there is ambiguity in the interpretation of science questions by different people. Generally PSLE science MCQ questions and O Levels science questions are carefully crafted and \"tested\" before being released for examination use. But even after the exams, questions are released and not the answers, so publishers take responsibilities to provide the \"correct\" answers.

Despite the imperfection of the \"MCQ\" exam, it constitutes 60% or a major portion of the PSLE so I usually urge my students to develop an inquiring mind to learn the right concepts from doing MCQ practices, rather than force themselves to accept any answers from the publishers without thinking and questioning. Remember that there is no \"perfect\" questions and \"perfect\" answers for some questions and that will take away the stress off the students to be perfect scorers. (which incidentally at my own P6 prelims I scored 100/100 for science in school many years ago)

[tianzhu]

Hi turquoise


Thank you for your response.

I also have my doubts regarding those given answers.

I think earthworm and bracket fungus are logical answers for Q1. (Note —ants are not listed as an organism under rotting log community in PSLE Revision Guide MPH, pg 203)

For Q2, I agree with you, earthworms can reproduce sexually and asexually. One can get such information from a Google search. One interesting point you brought up is your DD’s teacher’s comment. I will ask my boy to check with his teacher.

Best Wishes

[James Ang]

tianzhu:

Hi turquoise


Thank you for your response.

I also have my doubts regarding those given answers.

I think earthworm and bracket fungus are logical answers for Q1. (Note ---ants are not listed as an organism under rotting log community in PSLE Revision Guide MPH, pg 203)

For Q2, I agree with you, earthworms can reproduce sexually and asexually. One can get such information from a Google search. One interesting point you brought up is your DD’s teacher’s comment. I will ask my boy to check with his teacher.

Best Wishes

Earthworm lives in soil and feeds on dead leaves, there is no food on the rotting log for the earthworm to feed on, but there are dead leaves in the leaf litter community. That is the intention of the setter. Elimination method is a good way to narrow down the choices to the final correct answer since it is a clear cut question where there is only 1 answer.

You will get more headaches with the A only, A and B, A and B and C and all of the above, types of MCQ questions.

[James Ang]

Singapore Science quiz

Singapore is tops for Science in the whole wide world. Take this quiz to find out how good you are in Singapore’s PSLE - Primary School Leaving Examination (national level exam taken at 12 years old) Science!

1. What does an earthworm eat?
A) Earth
B) Green leaves
C) Dead leaves
D) Worm

2. What is vacuum made up of?
A) Nothing
B) Air particles
C) Smoke particles
D) Solid particles

3. The human baby develops in the mother’s
A) Ovary
B) Womb
C) Fallopian tube
D) Stomach

4. What is the gestation period of an elephant?
A) 12 months
B) 21 days
C) 22 months
D) 9 months

5. Which is heavier, 1 kg of Sand or 1 kg of Feather?
A) Feather
B) Cannot be compared
C) Same
D) Sand

6. Which of the below item is a simple machine?
A) Spear
B) Torchlight
C) Iron
D) Pulley

7. Which material listed below is magnetic?
A) Cobalt
B) Plastic
C) Aluminium
D) Copper

8. Which of the following has the greatest speed?
A) Sound
B) The Concorde supersonic jet
C) Light
D) Water

9. Choose the group with the greatest number of insects
A) Spider, earthworm, cockroach
B) Crab, prawn, coral
C) Caterpillar, mosquito, ladybird
D) Seahorse, mushroom, chicken

10. Which of the following animals have backbone?
A) Lobster, octopus, silverfish
B) Snake, frog, turtle
C) Rabbit, grasshopper, bird
D) Guppy, earthworm, snail

[James Ang]

turquoise:

tianzhu:

Hi

Thank you for your responses.

Q1) Organism A is most commonly found in leaf litter and rotting log community. Which one of the following organisms is Organism A most likely to be?

1) Earthworm
2) Ant
3) Grass
4) Bracket Fungus

The answer given in the WS is (4).

Which of the following organisms can reproduce by asexual reproduction?
E. Amoeba
F. Yeast
G. Earthworm
H. Bacterium

(1) E and F only
(2) E and H only
(3) E, F and H only
(4) All the above

The answer given in the WS is (4).

Hi tianzhu,

Which worksheet is this and how reliable are the answers given?

I can understand the ambiguity in the second question because some earthworms can reproduce asexually but my dd's teacher says the answer should not include earthworms at the PSLE level.

As for the first question, I really question if the correct answer should be bracket fungus.

Perhaps someone can enlighten us as to the correct answers.

Let's use the selection and elimination method to analyse this MCQ question scientifically and objectively.
The correct answer is bracket fungus for the following reasons (selection)
1) It is a decomposer.
2) It is found in both rotting log and leaf litter communities for organic materials to break down into simpler substances to be returned to the environment.
3) It lives in damp and dark conditions because fungi do not make food.

The wrong answers are not selected for the following reasons.(elimination)
1) They are not decomposers.
2) Earthworm feeds on dead leaves and not rotting log.
3) Grass and ants are more commonly found in field community.

Hope the analysis can strengthen the choice of answer in favour of bracket fungus. If there is a better analysis, please step forward for discussion.

[tianzhu]

Hi

Csc，tweet，Andaiz，JustKP，turquoise

Thank you for your responses to my questions. We tried hard, but arrived at different answers.

I am lucky to see this amazing site on rotting log. This should help our little ones find out more about rotting log community.

http://www.evergreen.ca/en/lg/lessons/rotting_log.html

\t，

[tianzhu]

James Ang:

Earthworm lives in soil and feeds on dead leaves, there is no food on the rotting log for the earthworm to feed on, but there are dead leaves in the leaf litter community. That is the intention of the setter. Elimination method is a good way to narrow down the choices to the final correct answer since it is a clear cut question where there is only 1 answer.

Hi James

Thanks for helping.I am quite confused.

Earthworm lives in soil and feeds on dead leaves,

Do earthworms feed on dead leaves alone?

[tianzhu]

James Ang:

Let's use the selection and elimination method to analyse this MCQ question scientifically and objectively.
The correct answer is bracket fungus for the following reasons (selection)
1) It is a decomposer.
2) It is found in both rotting log and leaf litter communities for organic materials to break down into simpler substances to be returned to the environment.
3) It lives in damp and dark conditions because fungi do not make food.

The wrong answers are not selected for the following reasons.(elimination)
1) They are not decomposers.
2) Earthworm feeds on dead leaves and not rotting log.
3) Grass and ants are more commonly found in field community.

Hope the analysis can strengthen the choice of answer in favour of bracket fungus. If there is a better analysis, please step forward for discussion.

Hi James

Please clarify why you narrow down Organism A down to decomposer only.Again, I am confused, from MPH PSLE Science Guide, pg 203, earthworm is classified as an organism in rotting log community.

[James Ang]

generally remember earthworm lives in soil and eat dead leaves;


below extracts from wikipedia


Biological. In many soils, earthworms play a major role in converting large pieces of organic matter (e.g. dead leaves) into rich humus, and thus improving soil fertility. This is achieved by the worm's actions of pulling down below any organic matter deposited on the dried dirt, such as leaf fall or manure, either for food or when it needs to plug its burrow. Once in the burrow, the worm will shred the leaf and partially digest it, then mingle it with the earth by saturating

Special habitats
While, as the name earthworm suggests, the main habitat of earthworms is in soil, the situation is more complicated than that. The brandling worm Eisenia fetida lives in decaying plant matter and manure. Arctiostrotus vancouverensis from Vancouver Island and the Olympic Peninsula is generally found in decaying conifer logs or in extremely acidic humus. Aporrectodea limicola and Sparganophilus and several others are found in mud in streams. Some species are arboreal. Even in the soil species, there are special habitats, such as soils derived from serpentine which have an earthworm fauna of their own.