Underwater Gliders

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What are Underwater Gliders?

Underwater Gliders are a type of robot that locomote through the water without a propeller or other method to push them forward. Instead, they rely on gravity and buoyancy to essentially “fly” through the water. As they sink or float, water flows past the wings, making them move forward as well. By alternating between sinking and floating, gliders move in a sawtooth motion. Using this method, gliders can be very energy efficient compared to other types of underwater vehicles, requiring very little battery use to move.


GUPPIE changes its buoyancy by taking in and expelling water from an internal syringe. Since GUPPIE is a lightweight vehicle,  weights are added until it is neutrally buoyant, floating just under the surface of the water. Then, when water is sucked in, GUPPIE sinks. After a predetermined time, water is expelled and GUPPIE starts to float up towards the surface again. GUPPIE’s wings allow for forward movement during sinking and rising.

Try it!

You can make your very own simple underwater glider using popsicle sticks and paperclips! Try arranging popsicle sticks together to make a glider with a body and wings, and add paperclips to achieve a proper trim. In a large tank or pool, place the glider in the water and see how far it can glide!