Variables that affect Magnetism Johannes Peters. Rationale o Social context: Magnetic Resonance...
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Transcript of Variables that affect Magnetism Johannes Peters. Rationale o Social context: Magnetic Resonance...
Variables that affect MagnetismJohannes Peters
Rationale
o Social context: Magnetic Resonance Imaging (MRI) scanners
Structure
o2 experiments
oMagnetic field strength
oMagnetic pulling force
Aim
o Experiment 1:o Effect of temperature on magnetic field strengtho Effect of distance on magnetic field strength
o Experiment 2:o Effect of distance on magnetic pulling force
Hypotheses
Experiment 1:o↑temperature ↓ magnetic field strength
o↑ distance ↓magnetic field strength
Experiment 2:o↑ distance ↓magnetic pulling force
Historical Background
o Hans Christian Oersted (1820)
o Magnetism + Electricity related
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Backgroundo Magnetic fieldo Electron motiono Magnetic moments & domainso Non magnetic materialso 1T=1000mT=1 000 000µT
Curie Temperature
o Random thermal motiono Magnetisation zero
MethodMagnetic field strength(Experiment 1) Magnetic pulling force (Experiment
2)
Mathematical relationship magnetic field strength, temperature and distance (Experiment 1)
Results (Table) (Experiment 1)
Average 1cm 2cm 3cm 4cm 5cm 6cm 7cm 8cm
40°C 7.6mT3.9mT 2.1mT 1.3mT 0.7mT 0.5mT 0.3mT 0.1mT
20°C8mT 4mT 2.2mT 1.3mT 0.8mT 0.5mT 0.3mT 0.2mT
10°C8.2mT 4.2mT 2.2mT 1.3mT 0.8mT 0.6mT 0.4mT 0.2mT
Effect of Temperature (Experiment 1)o Decrease approx. 7%
o Hoadley (2011) conducted similar tests, found a 8.5% decrease between 0-100°C.C
% decrease in field strength Round 1 Round 2 Round 3 Average
10-40°C -8.6412% -7.3170% -4.8192% -6.9261%
Magnetic pulling force and distance (Experiment 2)
Results
oMathematical relationship ( y=x -2 )
* y=magnetic field strength (mT) or magnetic pulling force (N)
* x=distance (cm)
oTemperature
Discussion
o Problems with method
o Social Context of results
©Waism
an Laboratory for Brain Im
aging & B
ehavior, 2007
Conclusion
o Decrease magnetic field strength :
→ Increased temperature and distance (Experiment 1)
oDecrease magnetic pulling force:
→ Increased distance (Experiment 2)
谢谢Thankyou