Using water waves to attract and repel

I have wondered how exchanging particles in atomic physics could attract and repel.



This seems to give me an example of waves (which sub atomic particles are to an extent) attracting.



http://ift.tt/1sYeezi

Quote:

Australian scientists have created the world's first water tractor beam which they hope can be used to clean up oil spills. Physicists at the Australian National University have created certain wave patterns in water that pull objects on the surface towards the source of the waves. It is hoped the tractor beam would be developed to assist in removing objects adrift on the surface of the ocean. Dr Horst Punzmann is part of the team behind the design."A tractor beam is a popular term which, I think it captures quite well the basic principle," he said. "You put an object there and it propagates, it floats backwards to the source of the wave." However, the physicists had been doubtful at first. "First I thought it was impossible and I thought that it was the effect of the boundaries nearby," said Professor Michael Shats, a colleague of Dr Punzmann.

via JREF Forum http://ift.tt/1p5sC8b