In this episode of O Wow Moments featuring Mr. O from the Children’s Museum of Houston, we play a little game called "Guess That Smell!" where we explore how our sense of smell works. It turns out that we are nanosensors - our noses actually sense molecules - things close to a billionth of a meter in size! But, as you'll see in this video, be careful about with whom you play the game... Many thanks to the Nanoscale Informal Science Education Network (NISE Net) and the National Science Foundation for funding this video.