 Japanese astronaut Kimya Yui returned to Earth last Friday after having spent about five months aboard the International Space Station. On station he spent much time performing the Dynamic Surf experiment that's helping us to better understand heat transfer in fluids. This is a space pod for December 16, 2015. Dynamic Surf is being conducted on behalf of JAXA, the Japanese Space Agency, in the Kyubo module of the International Space Station. It's looking at Marangoni Convection, which is where heat is transferred in a fluid due to differences in surface tension. So, surface tension is a force generated at the boundary between a liquid and a gas, such as water and air. You can see surface tension in action when you overfill a glass of water, and the top of the water seems to hover above the glass, but resist gravity and not spill over. Under normal circumstances, surface tension gets stronger with decreasing temperature. In the Dynamic Surf experiment, a bridge of silicone oil is suspended between two metal discs. One of the discs is heated while the other one is cooled, and this produces a difference in temperature, and thus a difference in surface tension. The silicone oil is pulled towards the cooler side thanks to Marangoni Convection. At first, this process produces a stable flow, but as the temperature difference gets larger and larger, the flow becomes more turbulent and eventually descends into chaos. Astronaut Don Pettit has even shown that Marangoni Convection can be induced just from the heat of a flashlight. Dynamic Surf is observing this in action by using cameras to measure the movement of tracking particles that are inserted into the liquid, and it's also tracking surface temperature at the same time. The International Space Station is a unique environment that allows us to perform experiments that we can't do on Earth. Dynamic Surf is no exception to this. Marangoni Convection is much weaker than buoyancy convection that's caused by gravity. That's the same force that causes hot air to rise and cold air to fall. So usually Marangoni Convection is overshadowed by its stronger cousin. Additionally, on Earth we can only create oil bridges, like the ones used in the Dynamic Surf experiment, a few millimeters long before gravity starts to cause some problems. On station, we've made oil bridges as long as 50 millimeters. So why is Marangoni Convection so important? Well, this force plays a destructive role in the production of crystals, such as silicon crystals for semiconductors. It's also a powerful force when dealing with micro amounts of fluid, like in DNA applications and other molecular biology techniques. And it's also important in heat transfer systems, like the heat pipe system that can cool personal computers. So ultimately, a better understanding of Marangoni Convection from Dynamic Surf and other related experiments can lead us to designing better heat transfer systems for the spacecrafts of tomorrow. Thanks for watching and I hope you learned a little bit more about Marangoni Convection than you knew before. If so, consider liking this video, subscribing to our channel and showing this video with your family and friends. You'll find more spaceports like this one at youtube.com. Space Ports are crowdfunded videos and we've totally revamped our Patreon campaign with new rewards and a convenient monthly pledge schedule. Thank you to all our existing patrons for helping us to bring cool space content to the world. If you'd like to know more, head over to patreon.com. My name is Lisa Stodzianowski and until next time, keep on discovering!