PBS
Pbs Learning Media: Frequency
In this interactive activity adapted from the University of Utah's ASPIRE Lab, students will investigate frequency in terms of trampoline jumps, pendulum swings, and electromagnetic waves.
Exploratorium
Exploratorium: Science Snacks: Strange Attractor
Explore the chaotic motion of a pendulum that is swinging above several magnets that are fixed in place and see what patterns you can find.