Photos: Robots as toys, tools and teachers

This version of the Bluefin, an underwater autonomous robot from Bluefin Robotics, based in Cambridge, Mass., is 9 inches in diameter and can function in water as deep as 650 feet. It has vents to allow for free flooding of the robot to avoid pressure problems. Only the main electronics are encased in a pressure-tolerant housing. The battery pack, specifically designed by Bluefin, is a lithium ion rechargeable battery that can last up to 12 hours at a time.

"It doesn't need a lot to deploy. Two guys can take it in a dingy and throw it in the water. We're very proud of that," said Deanna Abraham, a spokeswoman for Bluefin Robotics.