If you have Suns Java plug-in installed for your browser, an educational magnetic resonance Java Applet may have appeared above. If not, it is free, easy and safe to install using the pop-up installer (if this appeared in your browser) or by downloading Java from Sun Microsystems homepage. The applet can be used in an educational context in several ways. Initially, it is useful just to experiment with the applet to get a feel of the system components - most will discover magnetic resonance themselves while doing this. The following questions can also be addressed, for example (a ruler and a stop watch will come in handy).

• Determine how the needles natural oscillation frequency (the resonance frequency) depends on the B0 field created by the strong magnet. Which properties of the needle, is the frequency expected to depend on? (the latter question cannot be answered by using the simulator).
• Demonstrate how a magnetic needle in a strong magnetic field can be made to oscillate significantly with the help of a weak, perpendicular magnetic field. This is used in Magnetic Resonance Imaging (MRI) to get signal from magnetized tissues inside the body, since oscillating compass needles (magnetic dipoles) emit radio waves. What are the requirements for constant emission of relatively strong radio waves from the needle?
• Determine how the oscillation frequency and amplitude of the needle depends on frequency and amplitude of the B1 field created by the weaker magnet. For example, the amplitude response in steady state of the needle can be plotted against the driving frequency.
• Show the signal variation in a pulse-acquire experiment, where transmission of radio waves (oscillation of the weak magnet) is interleaved with measuring periods.