Hydrogen is the most abundant element in the universe. We have a lot of it on Earth and if we can safely use hydrogen fuel then it becomes a very appealing energy source because it turns into water when it burns. Because it’s such a small molecule, storing it is tricky because any tiny cracks or gaps will cause it to escape, which is generally a bad thing. This is why Jonas Welsch, a PhD student in Electrical Engineering at the University of British Columbia, is studying ultrasonic transducers and how they can be used to monitor for leaks. Katie and Vinny talk about hippos and teeny pulses of light.