Technology
Sharp metal propellers can harm wildlife, so an alternative made using ferrofluid could be a better approach, if it can be tweaked to work at higher speeds
By Alex Wilkins
A ferrofluid propeller powered by electromagnets
Hiroto Kitamori et al
A robot boat with a propeller made from liquid magnets could be a safer alternative than solid metal blades, which can damage wildlife.
Jun Shintake at the University of Electro-Communications in Chōfu, Japan, and his colleagues created a prototype aquatic craft with a propeller made from ferrofluid, which consists of magnetic iron oxide nanoparticles suspended in oil. It is controlled with electromagnets that switch on and off at high speed.
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