A simplified activity examined gas density while employing cost-efficient syringes in place of traditional glass bulbs. The exercise measured the density of methane, with very good accuracy and precision, in both first-year high school and AP chemistry settings. The participating students were tasked with finding the density of a gas. The discovery activity facilitated their understanding of the basis of the table of atomic masses. This activity should provide instructors of pre-AP and AP chemistry classes with an acceptably precise and accurate single-lab-period investigation that functions either within the gas law unit or introduction to atomic theory and atomic masses.