TITLE: The Nature of Magnetism

AUTHOR: John Forbes

SCHOOL: Savio Prep

SCHOOL ADDRESS: 94 Horace Street, East Boston, MA 02128

In my science project I studies the shielding of static magnetic fields. First I mapped the structure of the magnetic field (lines of force) of a bar and horse shoe magnet in the vertical and horizontal planes, in a shielded and unshielded state. I determined quantitatively, using a gaussmeter, the shielding of a magnetic field as a function of distance and temperature of employing glass, water, oil, iron, copper, zinc, (and combinations thereof) as shielding materials, including the effects of oxidation. My work also studied the decrease in magnetization of a magnet as a function of uniform heating of the magnet. I analyzed the difference between a dipole and quadrapole field, mapping the field intensities digitally in a horizontal grid. Additionally, I measured the current in a conductor crossing a magnetic field (or cutting a magnetic flux) as a function of velocity, the angle between the velocity vector and the magnetic field vector employing Lorentz's force-on-charge equation (F=g(E+vXB)). All measurements were made in millitesla and each of twenty-five separate experiments were conducted several times to show reproducibility. Finally I studied effects of a magnetic field combined with a gravitational field examining the spiral path of descent of iron filings through two immiscible shielding liquids.