The Curie Temperature

The Curie temperature for iron is reached at about 20 km depth in the Earth, and the temperature is much higher at the outer boundary of the Earth's core so that the iron there is no longer ferromagnetic (the electron spins in the iron can no longer align). This demonstration will help students understand the magnetic field of the Earth, and can help explain the variation of the direction of the field through time (the secular variation), the non-dipole field, and the fact that the field reverses its direction periodically (polarity reversals). Educational levels: High school, Middle school, Undergraduate lower division