Soft robots are more flexible than traditional machines and have the potential to squeeze into and explore more places. However, most of them need electronic components like circuit boards, valves and pumps to work. Those components are typically heavy, expensive and have to be tethered to the machines outside their body. Now, engineers from the University of California San Diego have developed a four-legged soft robot that doesn't need any of those to work -- in fact, the robot doesn't need any electronic component at all. Their soft robot has an onboard system of pneumatic circuits, which are made up of tubes and soft valves.

A soft robot, attached to a balloon and submerged in a transparent column of water, dives and surfaces, then dives and surfaces again, like a fish chasing flies. Soft robots have performed this kind of trick before. But unlike most soft robots, this one is made and operated with no hard or electronic parts. Inside, a soft, rubber computer tells the balloon when to ascend or descend. For the first time, this robot relies exclusively on soft digital logic.

A former NASA engineer has created a hot tub with a difference, filled with liquid sand that acts the same way as water, allowing him to float and splash around. Mark Rober, 37, from Orange County, California, is known for his quirky science based videos on YouTube. And for his latest post, he decided to customize a hot tub so he could experience the sensation of floating in liquid sand, known in science as a fluidized air bed. Experiment: During the video, Mark reveals how he created'liquified sand' using an old hot tub, copper pipes and pressurized air'I am sitting in a hot tub filled to the brim with solid sand. This is one of the coolest things ever,' Mark told the camera as he sat in his creation.

Imagine rescuers searching for people in the rubble of a collapsed building. Instead of digging through the debris by hand or having dogs sniff for signs of life, they bring out a small, air-tight cylinder. They place the device at the entrance of the debris and flip a switch. From one end of the cylinder, a tendril extends into the mass of stones and dirt, like a fast-climbing vine. A camera at the tip of the tendril gives rescuers a view of the otherwise unreachable places beneath the rubble.

Three years later, they emerge with a funnel-shaped robot that enfolds the mammalian heart, then actively compresses and twists it to restore normal blood flow after heart failure. Okay, so that's not how it actually happened, but the robot is real. Today, a team of researchers at Harvard University and Boston Children's Hospital, among other participating institutions, published details on an implantable, soft-robotic device that could help failing hearts pump blood without ever touching the blood. The work, including a proof-of-concept experiment with live pigs, was published this week in Science Translational Medicine. Traditional ventricular assist devices (VADs) are used to bypass a failing heart.