We have a designed a workshop that uses a handmade device to illuminate the concepts of heat, work, energy transfer, and thermodynamic path. The workshop, appropriate for general chemistry students, is done in two parts. In the first, students focus on the macroscopic aspect of the first law of thermodynamics, and in the second they develop a microscopic explanation for their macroscopic observations. Central to the workshop is a device designed at Hunter College to give students a feel for heat and work during gas compression. The device consists of a plastic syringe with a temperature probe sealed into the needle end. This is connected to an integrated circuit with a fast response time, which displays temperature. Students are asked to depress the syringe plunger rapidly and observe the temperature rise. This mimics an adiabatic process. The students also perform an isothermal compression. Working in teams and in response to several pointed questions, students are led to a mechanical interpretation of energy transfer in adiabatic and isothermal gas compressions. This mechanical interpretation provides deeper insight into nature of energy transfer implicit in the first law of thermodynamics.