CO2 Dry Cleaning: A Benign Solvent Demonstration Accessible to K–8 Audiences

A quick demonstration is described to showcase the use of CO, as an alternative, benign dry cleaning solvent. The demonstration includes visible evidence of CO, as a solid, a liquid, and a gas, making it ideal as part of a broader lesson on states of matter. The demonstration relies on a technique for generating liquid CO, in a centrifuge tube, which has been used for extractions in undergraduate teaching laboratories for over a decade. This report represents a unique attempt to transfer this method to the K-8 curriculum.