As my husband and I watched the Vikings game this Sunday, we sat shivering under blankets in our inefficiently heated apartment. If any of the players or live fans at that game would have traded positions with us, I’m sure our apartment would have felt more like a tropical paradise, no matter how inefficient the heating! As the players braved the cold, we watched as every movement was captured by their foggy breath, coming from warmed lungs into the cold air surrounding them.
When we exhale, our body is eliminating carbon dioxide waste from our bodies. Along with this carbon dioxide, we are also releasing water. Our breath collects moisture as it travels through our lungs, mouth, and other breathing passages. Inside our warm bodies, the moisture is in the form of gas or water vapor. The warm environment of our bodies provides energy for the water molecules to move very quickly and stay in their gaseous form. As soon as our breath is expelled into the cold, the molecules of water vapor slow down quickly and “huddle together” instead of spreading out as they do as gas. This slowing down of molecules results in what we call condensation, or the changing of a substance from gas to liquid form. The cold may be uncomfortable but it allows us to see this process of condensation right before our eyes as we breathe!