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