Surface tension is a phenomenon that we often encounter in our everyday lives. In this chapter, we present several examples from daily life, such as water droplets and soap films to illustrate the concept. We will also explain the balance of forces related to surface tension using an example of an air bubble and capillary rise in a thin tube. Furthermore, we will introduce and explain familiar examples, such as the tears of wine to illustrate thermocapillary and solutocapillary flows, which are induced by temperature and concentration gradients in liquids. When comparing the forces acting on fluid, the surface tension is usually smaller than buoyant or gravitational forces. Therefore, to conduct experiments eliminating the effects of gravity, we applied to a public call for experiment proposals for a scientific experiment in the Japanese Experiment, Module ‘Kibo,’ “Hope” in Japanese, on the International Space Station (ISS), and our proposal was selected. In the latter half of this chapter, we will introduce the ISS and Kibo, including a brief history of their construction, their structure, and major experimental facilities in Kibo. Even in ISS, variations in gravitational acceleration are unavoidable due to the operation of equipment and the activities of astronauts (known as g-jitter). Our experience of the g-jitter experienced in our Kibo experiment is also described.