Odors Aloft

Learners smell balloons filled with different scents to guess what's inside. From this, they infer the presence and motion of scented molecules. This is a good introduction to atoms and molecules, as well as an opportunity to talk about diffusion, states of matter, chemoreceptors and the sense of smell. For latex-sensitive learners, this activity also works with non-latex gloves. Extensions include measuring diffusion rates, and extracting essential oils from plant parts. Educator-led demonstrations include having learners act as molecules in a model of a solid, liquid, and gas, and then diffusing through a model membrane as a gas. Part of the "No Hassle Messy Science with a Wow" activity guide by OMSI, where all activities use only household materials.