GeoGebra Bubbles = Interactive Bubbles

This activity is from the Spanish GeoGebra book Cómo se hace... con GeoGebra. This construction uses javascript code based on the previous construction, which allows simulating the elastic collision of several circles or "bubbles". At all times we can:
  • Change the positions of the bubbles. Just drag the desired bubble.
  • Show or hide velocity vectors.
  • Change the length and direction of their velocities. To do this, it is recommended to stop the animation (clicking on the almost invisible Play/Stop button, in the bottom left corner of the graphical view) momentarily and move the arrowheads (velocity vectors) as desired.
  • Change the number of bubbles, up to a maximum of 20.
  • Change the radius of the bubbles, up to a maximum of 2 units.
  • Change the speed of the animation.
Due to the limited space of the stage and the respective speeds of bubbles, it is recommended to use an animation speed not too high, as well as seeking a balance between the number of bubbles and the radius of each one. Otherwise, they may appear temporarily undue overlaps. Note that the total kinetic energy does not vary as long as we do not vary the number of bubbles or their vectors. Taking the constant amount of 2 units as the mass of each bubble, that energy is the result of which appears in the construction.
Author of the GeoGebra activity and construction: Rafael Losada.