Chances are you’ve seen the gorgeous patterns that sound waves produce when sand is sprinkled on a vibrating metal plate. Now French physicists have produced inverse versions of these patterns using microbeads suspended in a liquid. They described their work in a recent paper in Physical Review Letters.
You’ve probably watched enough Animal Planet to know that humpback whales communicate using clicks and whistles. But put on a pair of headphones and listen to the video above. Beneath the shrill chatter we’ve all heard before, there’s a much lower-pitched tone, eerily reminiscent of a human heartbeat.