The Effects of Temperature on Magnetic Strength

Joseph Gault

Grade 9

February 2, 2008

Pittsburgh Central Catholic High School

Types of Magnets

• Ceramic – composed of

powdered iron oxide and

strontium carbonate

ceramic; it is the most common magnet

because it is cheap and easy to produce

• Ticonal - alloy of titanium, cobalt, nickel,

and aluminum; developed by Philips for

loudspeakers

Types of Magnets (cont.)

• Injection molded - composite of various types of resin

and magnetic powders, allowing parts of complex

shapes to be manufactured by injection molding;

generally lower in magnetic strength and they

resemble plastics

• Electromagnet - a wire that has been coiled into one or

more loops

– electric current flows through the wire, causing a

magnetic field to be generated

– commonly used in electric motors, junkyard

cranes, and medical equipment, such as an MRI

machine

Uses of Magnets

Common uses for magnets:

• VHS Tapes

• Audio Tapes

• Floppy Discs

• Hard Drives

• Credit Cards

• Televisions

• Speakers

• Microphones

• Compasses

Purpose

• The purpose of this experiment was to determine:– If the strength of a magnet would be

altered when placed in temperature zones less than room temperature, and warmer than room temperature.

– If the strength of the magnet would remain changed when the magnet returned to room temperature.

Null and Alternative Hypothesis

Null:• Temperature changes will not

significantly affect the magnetic strength of the magnets.

Alternative:• The various temperature zones will

significantly affect the magnets’ strengths.

Materials

• -80°C Freezer• -20°C Freezer• -4°C Refrigerator• Room at 20°C• 45°C Incubator• 100° Drying Oven• 30 Ceramic Magnets• Extech True RMS Digital

Multimeter • Gauss Attachment• Tongs• Gloves• HP 39GS Graphing Calculator

Procedure

1. 30 magnets were labeled (1-5) for 6 different temperature zones.

2. The magnetic strength of each magnet was measured with a voltage meter, and converted to Gauss using the following equation:

B = 1000*(V0-V1)/k.3. The 5 magnets of each group were

placed into the following environments:

-80°C Freezer-20°C Freezer4°C RefrigeratorRoom TemperatureIncubator – 45° CDrying Oven – 100° C

Procedure (Cont.)

4. The temperature of each magnet was measured immediately after the magnets were removed from the environments.

5. The magnetic strength of each magnet was measured immediately after removal from the temperature zone.

6. Data was recorded.7. The magnets were allowed to return

to 20°C.8. The magnetic strength of each magnet

was measured.9. Data was recorded.

Experiment

Incubator

4°C

Drying Oven

Room Temperature

Recording the Magnet’s Strength

Results and Conclusions

• The north and south poles of the magnets in the 4° refrigerator and 100° drying oven were significantly affected by the variation in temperature when they were immediately removed from the temperature zone.

• The north and south poles of the magnets in the 45° incubator and 100° drying oven were significantly affected when the magnets returned to room temperature.

• My null hypothesis, stating that the various temperature zones will not affect the magnets’ strengths, was supported by the magnets in the 4° and 100° temperature zones.

• The magnets below 4° were affected by the temperature changes.

• The magnets ranging from 20°C to 45°C were affected by the temperatures when immediately removed from the temperature zones.

Results and Conclusions

Limitations and Extensions

• Two of the magnets stuck together. This prevented me from recording their strengths when they were taken out of the temperature zone.

• I was unable to record the strength of the magnets while they were in the varying temperature zones. I had to remove them to record their strengths, and they began to return to 20°C.

• In the future, I would apply colder and warmer temperatures to the magnets, and try different methods of heating and cooling the magnets, such as using dry ice, or boiling water.

Resources/Acknowledgements

• http://en.wikipedia.org/wiki/Magnet• http://www.usc.edu/cssf/current/

projects/j1613.pdf• How Things Work Volumes 1-4• Fundamentals of Physics • They Feynman Lectures on Physics• The New Way Things Work• My father and my teacher for

supervising my project • My mother for proofing my project