TOPIC: EFFECT OF TEMPERATURE ON MAGNETIC STRENGTH

1. Physics Investigatory Project
(2017-2018)
Submitted by: Vasu Yadav
Of Class: XII-A

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This is to certify that the projectentitled “TO STUDYTHE EFFECT OFTEMPERATURE
ON MAGNETIC STRENGTH”is a bonafide work carried out by VASU YADAV studying
in class XII-A at KENDRIYA VIDYALAYA, JANAKPURI, NEW DELHI affiliated to
Central Board of Secondary Education under guidance MR. MANOJ KUMAR(P.G.T.
Physics). He has successfully completed the project work on physics for class XII practical
examination in the year 2017-2018. It is further certified that the matter embodied in this
project is the individual work of the Candidate.
Signature:
Date:

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Before I get to think of things, I would like to thank from my heart, people who were directly
orindirectly involved during the completion ofmy project titled “TO STUDYTHE EFFECT
OF TEMPERATURE ON MAGNETIC STRENGTH”.
First of all, I would like to thank respected, Mr. V.K. YADAV (PRINCIPAL), who gave me
the opportunity to carry out the project in this esteemed institute. A grateful acknowledgement
goes to MR. MANOJ KUMAR (P.G.T. PHYSICS). He provided me with all the valuable
and necessary information, which was required for the completion of the project. She helped

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me with timely suggestions during the entire period of references and data collections and
support, closescrutiny and co-operationwithout which it would not have been possiblefor me
to undertake and complete the project.

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Magnets are frequently used in daily life. For example, magnets are used in
manufacturing, entertainment, security,andtheyplayacrucialroleinthe

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functioning of computers. Even the earth itself is a magnet.
A magnet is any object that produces a magnetic field . Some
magnets, referredtoaspermanent, hold theirmagnetism without an
external electric current. Amagnet ofthisnature canbecreatedby
exposing apieceofmetal containing iron toa number ofsituations (i.e.
repeatedly jarring the metal, heating tohigh temperature). Soft magnets,
onthe otherhand, are those that lose their magnetic charge properties
over time. Additionally, paramagnetic objectsarethosethatcanbecome
magnetic only when inthe presence of an external magnetic field.
A magnetic field is the space surrounding a magnet in which magnetic force
is exerted. The motion of negatively charged electrons in the magnet
determines not only the polarity,but also the strength of the magnet (Cold
magnet).
Magnets are filled with magnetic lines of force . These lines
originate at the north pole of the magnet and continue to the south pole.
The north pole is positive. Magnetic lines of force do not intersect one
another.
Magnetism iscreatedby the alignment ofsmall domains within a
specificsetof metal. These domains function asall atoms do, thus the
temperature affectsthe movement. The higher the heat, the greaterthe
energy, and as such the movement of the particles. In contrast, cold
temperature slows the movement (magnetic Field Strength and Low
Temperatures). Slower movement leads to more fixed directions in terms of
the domains.
In the 1800’s, Pier4re Curie discovered that there exists a
temperature at which objects that were previously permanently
magnetic lose this characteristic .The temperature atwhich this
demagnetization occursis called the “Curie point”. As thetemperature of
the magnet approaches this point, the alignment ofeachdomain
decreases. As such, the magnetism decreases until the Curie point is
reached, at which time the material becomes paramagnetic.

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OBJECTIVE:
TO DETERMINE THE EFFECT OF TEMPERATURE
ON MAGNETIC STRENGTH
HYPOTHESIS:
It is believed that the colder the magnet, the stronger the
magnetic force. Graphically, the results will resemble an
exponential curve, with magnetic forcedecreasing astemperature
increases. Our independent variable is temperature. Our
dependent variable is magnetism; this will be calculated using the
amountofpaperclipsthatthemagnetisabletocollectateach
measured temperature

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• Safety glasses
• 3-4 permanent bar magnets
• Tongs for magnet
• Ice
• Water
• Insulating container
• Three strong bowls
• Small pot
• Burner for heating water or oven
• Paper clips(1000)

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THEORY
Amagnet is amaterial orobject that produces amagnetic field. This
magnetic field is invisible but is responsible for the most notable
property ofamagnet: aforcethatpulls onotherferromagnetic
materials, suchas iron, and attracts or repels other magnets.
A permanent magnet is an object made from a material that is
magnetized and creates its own persistent magnetic field. An everyday
example isa refrigeratormagnet used to hold notes ona refrigerator
door. Materials that can be magnetized, which are also the ones that
are strongly attracted to a magnet, are called ferromagnetic (or
ferrimagnetic). These include iron, nickel, cobalt,some alloysofrare
earth metals, and some naturally occurring minerals such as lodestone.
Although ferromagnetic (and ferrimagnetic) materials are the only ones
attractedtoa magnet strongly enough to be commonly considered
magnetic, allothersubstances respond weakly toamagnetic field,by
one of severalother types of magnetism.
Ferromagnetic materials can be divided into magnetically "soft"
materials like annealed iron, which can be magnetized but do not tend
to stay magnetized, andmagnetically "hard" materials, whichdo.
Permanent magnets aremade from"hard" ferromagnetic materials
suchasalnico and ferrite that are subjected to special processing
in a powerful magnetic field during manufacture, to align their internal
microcrystalline structure, making them veryhard todemagnetize. To
demagnetize a saturated magnet, acertainmagnetic field must be
applied, and this threshold depends on coercivity of the respective
material. "Hard" materials have high coercivity, whereas "soft"
materials have low coercivity.
The overall strength of a magnet is measured by its magnetic moment
or, alternatively,thetotalmagnetic flux itproduces. The local
strength of magnetism in a material is measured by its
magnetization.

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ColdProcess
1. Place paperclips inbowl.
2. Situate scale near bowl.
3. Weigh magnet and record.
4. Place magnet and freezer thermometer in freezer set to
lowest temperature possible.
5. Waitapproximately 20minutes forthemagnet toreachthe
temperature of the freezer.
6. Record temperature read by freezer thermometer.
7. Place magnet in bowl filled with paperclips.
8. Remove magnet and attached paperclips and place on scale.
9. Record temperature of magnet and grams attracted.
10. Subtract the weight ofthe magnet fromthe weight ofthe magnet
and the paperclips combined.
11. Remove paperclips and place back in bowl.
12. Set freezer to 5-Celsius degrees higher than previous
temperature. (Note: freezer accuracy is dubious. Use
temperature read by freezer thermometer)
13. Repeat steps 4-12 until freezer and magnet have reached zero
degrees Celsius.

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HotProcess
1. Place paperclips in the bowl.
2. Situatescale nearbowl.
3. Weighmagnetand record.
4. Place magnet in oven set to highesttemperaturepossible.
5. Waitapproximately20minutesforthemagnetto
reachthe temperature of theoven.
6. Place magnet in bowl filled with paperclips.
7. Remove magnetandattachedpaperclipsandplaceonscale.
8. Record temperatureof magnetand grams attracted.
9. Subtracttheweightofthemagnetfromtheweightof
the magnet and the paperclipscombined.
10. Remove paperclipsand place back in bowl.
11. Allow magnet to rest for 5 minutes undisturbed.
12. Repeatsteps6-11 untilmagnetreachesroom temperature.

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1. MAGNET UNDER EXTREME HEAT
Time after removal
from oven (minutes)
Weight attracted
(in grams)
0 200
5 200
10 240
20 210
25 230
30 220
35 206
180
190
200
210
220
230
240
o
5
10
20
25
30
35
200
200
240
210
230
220
206
WEIGHT(GRAMS)
TIME (MINUTES)

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2. MAGNET UNDER EXTREME COLD
Temperature Weight
-21.3 275
-19.4 275
-18.1 265
-15.3 270
-13.7 260
-6.7 245
0 225
0
50
100
150
200
250
300
-21.3
-19.4
-18.1
-15.3
-13.7
-6.7
0
275 275
265 270
260
245
225
WEIGHT
TEMPERATURE

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CONCLUSIONS:
Magnetic materials should maintain a balance between
temperature and
magnetic domains (the atoms’ inclination to spin in a certain direction).
When exposedtoextreme temperatures, however,thisbalanceis
destabilized; magnetic properties are then affected. While cold
strengthens magnets, heat canresult inthe lossof magnetic properties. In
otherwords, toomuch heat cancompletely ruin amagnet. Excessive
heat causes atoms to move more rapidly,disturbing the magnetic
domains. As the atoms are sped up, the percentage of magnetic domains
spinning in the same direction decreases.
This lack of cohesion weakens the magnetic force and eventually
demagnetizes it entirely.
In contrast, when a magnet is exposed to extreme cold, the atoms slow
down so the magnetic domains are aligned and, in turn, strengthened.
Ferromagnetism
The way in which specific materials form permanent magnets or interact
strongly with magnets. Most everyday magnets are a product of
ferromagnetism.
Paramagnetism
Atype ofmagnetism that occurs only inthe presence of anexternal
magnetic field. They are attractedtomagnetic fields, but they are not
magnetized when the external field is removed. That's because the atoms
spin in random directions; the spins aren’t aligned, and the total
magnetization iszero.
Aluminum and oxygen are two examples of materials that are
paramagnetic at roomtemperature.
Curie Temperature
Named for the French physicist Pierre Curie, the Curie Temperature is the
temperature at which no magnetic domain can exist because the atoms
are too frantic to maintain aligned spins. At this temperature, the
ferromagnetic material becomes paramagnetic. Even if you cool the
magnet, once it has become demagnetized, it will not become magnetized
again. Different magnetic materials have different Curie Temperatures, but
the average is about 600 to 800 degrees Celsius.

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BIBLIOGRAPHY:
www.icbse.com
www.sciencebuddies.com
www.technopedia.com
www.wikipedia.com
NCERT Physics book
www.howmagnetswork.com
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