Q&A - PSLE Science

[Belle2011]

atutor2001:

I guess you must have read somewhere that magnetism pass through ALL materials (including magnetic material), which is actually correct.

This is the tricky part; in school nothing much was mentioned and we have a feeling that magnetism can't pass through magnetic materials.
But when you put a magnet near an iron nail, this iron nail can in turn attracts some iron filings or paper clips which means the magnetism has passed from the magnet to the iron nail.
I am getting more and more confused.
Cheers,
Belle.

[tianzhu]

Belle2011:

May I find out if magnetism can pass through magnetic materials?

Belle2011:

This is the tricky part; in school nothing much was mentioned and we have a feeling that magnetism can't pass through magnetic materials.
But when you put a magnet near an iron nail, this iron nail can in turn attracts some iron filings or paper clips which means the magnetism has passed from the magnet to the iron nail.
I am getting more and more confused.

Hi

In PSLE science, students learned that magnetic force cannot pass through magnetic materials.

What you’ve described is an example of magnetism by induction. The iron nail is magnetised by induction.

Best wishes

[atutor2001]

tianzhu:

What you’ve described is an example of magnetism by induction. The iron nail is magnetised by induction.

Best wishes

Magnetic induction is the result of magnetic force passing through the iron nail (a magnetic material). I have copied this write-up from the internet :

\"As an iron nail is brought close to a bar magnet, some flux lines emanating from the north pole of the magnet pass through the iron nail in completing their magnetic path. Since magnetic lines of force travel inside a magnet from the south pole to the north pole, the nail will be magnetized in such a polarity that its south pole will be adjacent to the north pole of the bar magnet. There is now an attraction between the two magnets.\"

For those interested, you may visit this site
http://www.tpub.com/neets/book1/chapter1/1i.htm

In my opinion, it is important to teach our kids the truth and also to accept the limitation of the primary science syllabus - recognising the difference in definitions of the words used.

[tianzhu]

Hi Belle2011


You may wish to try out these questions. I think it’ll help.

Do a recap of what you’ve been in lower primary science.
Magnetism refers to the pull of a magnet, the magnetic force of attraction and repulsion.

Q3 and Q4 of this link.
http://www.oldschool.com.sg/index.php/module/PublicAccess/action/Wrapper/sid/597167a402eb2fb7800f02ccf96c7860?srch_str=&sub_cat_nm=Magnets&qn_type=QN&cat_grp_id=69&srch_press.x=43&srch_press.y=12

Q10 of this link.
http://www.oldschool.com.sg/index.php/module/PublicAccess/action/Wrapper/sid/597167a402eb2fb7800f02ccf96c7860?srch_str=&sub_cat_nm=Magnets&qn_type=QN&cat_grp_id=85&srch_press.x=36&srch_press.y=9

Best wishes

[ParentingChildren]

Don’t think the concept of magnetic shielding is in the Primary Science Syllabus.

[Nebbermind]

ParentingChildren:

Don't think the concept of magnetic shielding is in the Primary Science Syllabus.

obviously not. but there are enough diagrams to to illustrate how the magnetic fields are altered when a magnetic material is placed near the magnet. Even if the diagrams are not helpful, the term 'magnetic shielding' is kinda self explanatory

[meimeitan]

Hi Good morning,


Anyone can help the following question?

Tubes grow from the pollen grains towards the ovary to pass __________
(1) the pollen grains to the ovules
(2) nutrients and water to the ovules
(3) the female egg cells to the ovules
(4) the male reproductive cells to the ovules

Thanks.

[starlight1968sg]

meimeitan:

Hi Good morning,


Anyone can help the following question?

Tubes grow from the pollen grains towards the ovary to pass __________
(1) the pollen grains to the ovules
(2) nutrients and water to the ovules
(3) the female egg cells to the ovules
(4) the male reproductive cells to the ovules

Thanks.

I think is (1). Let us hear what the other say.

[Nebbermind]

IIRC, shd be (4)

[csc]

i think it is (4) too.


Where is tianzhu?