Q&A - P3 Science

[elkniwt]

Hi,


Need help to clarify this marking by my dd's teacher.

There's this question on an experiment. It shows a magnet attracting many nails. Then after the magnet is heated, it shows the number of nails attracted by the magnet is greatly decreased. And the qn asked : What does the experiment above show about magnets?

My dd's ans is \"If you heat a magnet, it will lose its magnetism.\" And it was marked wrong. Her teacher's ans is \"A magnet loses its magnetism when heated.\" What's the difference?? :?

Another qn, there's a picture of sweet potato and question asks for identification of the part and function of the part. dd got right for first part. (ans is roots) but she was marked wrong for 2nd part on function. Her ans is \"It stores the food for the plant.\" Teacher's ans is \"It takes in water for the plant.\"

[acforfamily]

elkniwt:

Hi,


Need help to clarify this marking by my dd's teacher.

I don't see anything wrong with your dd's answer at all !

[watmekiasu]

elkniwt:

watmekiasu:

But one of my stapler does have a magnetic catch.


The expected answer is C and D. Pianos do not have magnets.

Hi,

I downloaded my paper from misskoh.com and the ans is 3 (B, C and D only). Is your ans key different from mine?

I did not include in the stapler because most staplers use spring pivots. I'd always assumed my magnetic one is kinda rare. It's actually so rare that I had a hard time looking for the right size bullets. :roll: The answers on MsKoh.com are sometimes arguable. It is good you brought up this question cos hopefully, a current teacher here will give us the definative answer.

[tutormum]

elkniwt:

Hi,


Need help to clarify this marking by my dd's teacher.

There's this question on an experiment. It shows a magnet attracting many nails. Then after the magnet is heated, it shows the number of nails attracted by the magnet is greatly decreased. And the qn asked : What does the experiment above show about magnets?

My dd's ans is \"If you heat a magnet, it will lose its magnetism.\" And it was marked wrong. Her teacher's ans is \"A magnet loses its magnetism when heated.\" What's the difference?? :?

Another qn, there's a picture of sweet potato and question asks for identification of the part and function of the part. dd got right for first part. (ans is roots) but she was marked wrong for 2nd part on function. Her ans is \"It stores the food for the plant.\" Teacher's ans is \"It takes in water for the plant.\"

Both your dd's answers are correct. I think you should have a word with her teacher. For the second question, unless it is specified, students have an option to put either of the answers, that is, it stores food for the plant or takes in water for the plant. I usually give my students all available answers even if only 1 is required. The reason is, if the question gives a function e.g. the roots of the sweet potato takes in water for the plant, name another function, the student will know how to answer the question. Imagine if the student only knows that it takes in water.
I have come across once when the school teacher gave wrong answers from the answer keys despite some of the students protesting that the answers were obviously wrong. My student's mum took a double take when she found that some of the common sense questions were obviously wrongly marked. My student lost confidence and 'switch off' during lessons. I went through every single piece of my student's school work to make sure that she didn't learn the wrong thing. It was after about 2 months that the teacher realised her mistake. :!: Worse, it was the PSLE class.

[elkniwt]

Thank you, tutormum. I also think that my dd's answers are acceptable. But just need some assurance and support. :hugs:

[Tang]

elkniwt:

Hi,

Another qn, there's a picture of sweet potato and question asks for identification of the part and function of the part. dd got right for first part. (ans is roots) but she was marked wrong for 2nd part on function. Her ans is \"It stores the food for the plant.\" Teacher's ans is \"It takes in water for the plant.\"

The teacher's answer for the function of sweet potato may not be correct.
Sweet potato does not take in water, it is the fine roots that absorb the water and mineral salts. Sweet potato basically stores food.

For the first part, the complete answer should be 'underground root'.

[tutormum]

Perhaps this will help.


The sweet potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the family Convolvulaceae. Amongst the approximately 50 genera and more than 1,000 species of this family, only I. batatas is a crop plant whose large, starchy, sweet tasting tuberous roots are an important root vegetable (Purseglove, 1991; Woolfe, 1992). The young leaves and shoots are sometimes eaten as greens. The sweet potato is only distantly related to the potato (Solanum tuberosum). The softer, orange variety is commonly marketed as a yam in parts of North America, a practice intended to differentiate it from the firmer, white variety. The sweet potato is very distinct from the other plant known as a yam (in the Dioscoreaceae family), which is native to Africa and Asia. To prevent confusion, the United States Department of Agriculture requires that sweet potatoes labelled as \"yams\" also be labelled as \"sweet potatoes\".[1] :grphug:

[glchua]

Tang:

The teacher's answer for the function of sweet potato may not be correct.

Sweet potato does not take in water, it is the fine roots that absorb the water and mineral salts. Sweet potato basically stores food.

For the first part, the complete answer should be 'underground root'.

Without looking at the actual question, and judging as it is, I think the question is poorly drafted.

The potato plant uses it's roots to store food. So the primary function of that part of the plant we call \"potato\" is as a root, that is, to take in minerals and water. Storing food is a secondary function. This is the same for ginger, tapioca etc.

It is like many science questions I see in primary school, very poorly done. If a student think more, he'll get answers wrong.

[glchua]

watmekiasu:

I did not include in the stapler because most staplers use spring pivots. I'd always assumed my magnetic one is kinda rare. It's actually so rare that I had a hard time looking for the right size bullets. :roll: The answers on MsKoh.com are sometimes arguable. It is good you brought up this question cos hopefully, a current teacher here will give us the definative answer.

Every version of thing that we bought may have a magnet somehow to enhance it's original function. However, a magnet has no actual role in a piano or a stapler. I think the answer is strictly C (telephone) and D (fridge) only.

Most microphones or speakers need magnets, fridge has a motor (compressor) so it definitely needs one.

You don't need magnets in staplers for it to function. You don't need a magnet in a piano. But both items may on and off have magnets to make it function better. I had seen a piano with a magnet before, anyone want to make a guess where it is?

Again, another very vague question. If a child had seen a magnet in a piano or a stapler, he would get this wrong.

[Tang]

glchua:

Without looking at the actual question, and judging as it is, I think the question is poorly drafted.


The potato plant uses it's roots to store food. So the primary function of that part of the plant we call \"potato\" is as a root, that is, to take in minerals and water. Storing food is a secondary function. This is the same for ginger, tapioca etc.

It is like many science questions I see in primary school, very poorly done. If a student think more, he'll get answers wrong.

If the arrow is pointed at the sweet potato, then it is correct to state that its function is to store food.

The roots (fine roots - refer to diagram) take in water and mineral salts, not the sweet potato.

In fact a better answer is 'It is for reproduction'.

Refer to Q6 of Henry Park Prelim 2007
http://www.wendykoh.com/07/primary6-henrypark-science.pdf


Similarly for potato, ginger and tapioca, they do not take in water and mineral salts. Their functions are to store food and for reproduction.