Water is so abundant, we often take for granted how remarkable and unusual it is. Water is the only substance on our planet that can exist naturally in all three states of matter: as a solid, a liquid, and a gas. Water also has seven other incredible properties: cohesion, adhesion, surface tension, capillary action, high specific heat, universal solvent, expands when frozen. In our first video and guide, we use three fun investigations to explore cohesion—the ability of water molecules to stick to each other.