angry tapir writes "Scientists are developing a robotic jellyfish which uses the limitless energy of sea water to power its movement. US Navy-backed research, published on Wednesday, says "Robojelly" mimics the action of the jellyfish, which uses a circular muscle to open out a bell-like body and then sharply close it, which expels water and moves the creature forward. The robot's body comprises eight segments made of shape-metal alloy — metals that remember their original shape after being scrunched up. They are coated with a platinum black powder, which reacts with the oxygen and hydrogen components of sea water to create heat."
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