Particle Gravity Simulator

You can use this app to create cool simulations of particles and their interactions from gravity. There are options for setting different colors, sizes, and strength of the gravitation force exerted by each particle on others.
There are different options for what happens when a particle hits the edge of the screen. Stop - The particle loses it's velocity from the direction it hit the screen. Bounce - The particle's velocity from the direction it hit the screen is reversed and it bounces off the edge. Continuous - The particle continues outside the screen and follows along the same path it would have, possibly reentering the screen. Multiply - The particle behaves like Bounce, but has a second particle created that Bounces in the opposite direction. (This can lead to many particles quickly which (Because of all the Math and Physics involved) can cause considerable lag. I put it in because it can give some cool effects if done right. I usually use few particles on very low gravity.)
Other features are Center Objects which will not be affected by the gravitational force of other objects on the screen, but will still act on the other objects. The two center objects are Sun and Black Hole. Each of their gravitational forces can be set individually, but only one Center Object can be on the screen at a time.
My favorite setting is the grid setting. It allows you to automatically place particles in symmetrical grids. You choose the rows and columns for the grid and hit add. For this one, something cool is to create a grid with all the particles having zero gravitational force, and have a center object with just a little.
One of my current plans for this are to create an option Tails sets an amount of smaller particles that appear in the last few positions of particles. (This has been added in version 1.14 :) )
Another is to create different settings for placing shapes of particles on the screen. Some examples would be a rectangle of particles, a circle, or a star. If there is something you would like in this app, then leave a comment. Who knows what could appear in the next update. :)
Also, the internet permissions is needed to load ads. Maybe this poor college student can make a buck or two from his hobby. :)