I am trying to simulate this effect…https://vimeo.com/109020378 [vimeo.com]

I have an emitter that fills a cup and I made the main density 1000 for the water.

I made a small percentage of the emitter a lower density 800 so that the particles would float to the surface.

This is working perfectly.

Next I select a few particles to copy stamp spheres and resize based on pscale. This is not working as expected as the particles seem to be dying and popping. I would like to know if the above example is using a similar method or am I completely on the wrong track?

Thanks in advance for any guidance.