Two physics simulations:

Pendulum-Simple Harmonics: 15 pendulum simple harmonic oscillation demonstration. The period of each pendulum is 1 second longer than the previous pendulum. This creates a 60 second cycle where the pendulums move in and out of “harmony”, creating patterns in the swings.

Rope Bridge: This simulation demonstrates 2D physics with collisions and accelerometer based gravity. Several bouncing balls on the screen will collide with one another and a 25 segment elastic rope which acts as an acceleration dampener.

Have fun playing with it. Oh, and children really like the bouncing balls.