Electromagnetism U. Penn. Helps arouse interest in one of the oldest branches of physis. Suitable for graduate students, their teachers, and researchers in ultrasonics or otherwise interested in this field. You may be interested in Physics Classroom A very neat high-school level presentation of many interesting topics in physics, including sound, light, and machanics. From Glenbrook South.
Special features are some short animation to demonstrate concepts.
Also includes questions to check understanding. Very easy to use when you look for some material on a specific subject. Check out this place for very useful materials. A truly impressive effort to collect materials suitable for kids from kindergarten to university graduate, sponsored by the Science Education Program Office of U. California at Irvine. Logically presented, suitable for preparing curricula.