Page 109 - Physics_Form_2
P. 109
Magnetism
Procedure process is repeated several times. The
1. Fill in the small glass or plastic jar pole produced at the end of the stroke
with iron filings. is always the opposite of that at the end
2. Examine the filings using a of the magnet used for stroking. For
example, if the north pole of the magnet
magnifying glass, a digital is used for stroking, then the rod will be
FOR ONLINE READING ONLY
magnifying camera, or a smartphone magnetised such that its starting end will
with a magnification app, and take act as the north pole and the other end as
clear images or videos. the south pole, as shown in Figure 3.19.
3. Now, place the jar of filings alongside
a strong bar magnet and gently shake
the jar for a few seconds.
4. Use the magnifying device again
to observe the images or videos as
shown in Figure 3.18 and use image
analysis software to compare the nitially
arrangement of filings before and unmagnetized
nail
after magnetisation.
Jar of iron filings Figure 3.19: Single-touch method
After completing stroking, care has to be
taken not to move the magnet close to
the nail because this is taken as a repeat
stroke. It disorganises the already aligned
dipoles. The stroking method, whereby
Figure 3.18 only one magnetising magnet is used, is
called a single-touch method. When two
Questions magnets are used, the method is called
(a) What did you observe from the a double-touch method. In this process,
recorded images or videos? the ends of two magnets of different
(b) Explain your observations based on polarities are positioned at the middle of
the behaviour of magnetic materials. the iron nail. The two magnets are then
moved in a curved motion in the opposite
In the second magnetisation method, a directions as shown in Figure 3.20. The
piece of unmagnetised material is stroked iron nail is stroked a few times along its
using a magnet. An existing magnet is length. This procedure must be done with
moved from one end of the material to care to ensure the proper magnetisation of
the other in the same direction. This the iron nail.
103
Physics Form 2 Final.indd 103 25/10/2025 10:26
