1. Magnetism and Magnetic Materials DTU (10313) – 10 ECTS KU – 7.5 ECTS Module 8 25/02/2011 Permanent magnets Macro –  m-mm

2. Intended Learning Outcomes (ILO) (for today’s module) 1.Explain how a small piece of graphite can levitate 2.Build a magnetic levitation device 3.Construct a dipolar magnet and maximize its strength 4.Quantify the lifting force of a magnet 5.Describe the magnetic-to-kinetic energy transfer in a simple magnetic gun

3. Magnetic levitation Dipolar magnets A simple magnetic gun Think about how to use a set of magnets to levitate an object Build a magnetic levitation device together with your group Explain to the class the working principles of your levitation device Play around with magnetic hard spheres, assemble them into various shapes and orderings (ferromagnetic and anti-ferromagnetic arrangements) Measure fields with the hall probe device Construct the most powerful magnet you can think of by using your set of spheres Compete with the other groups and develop the largest lifting force (to be measured with a digital balance) Look at the demonstration, try it out for yourself, and figure out how it works

4. Wrapping up Next lecture: Tuesday March 1, 13:15, KU (A9) Order and broken symmetry (KL) Dipolar ferromagnets and anti-ferromagnets Chains, necklaces, vortices, shapes… Diamagnetic and ferromagnetic levitation The simplest magnetic gun: magnetic-to-kinetic energy transfer