# 09 First Law of Thermodynamics

## Idealized Stirling Cycle

I created a new GeoGebra app based on an ideal Stirling Cycle (A. Romanelli Alternative thermodynamic cycle for the Stirling machine, American Journal of Physics 85, 926 (2017)) which includes two isothermal and two isochoric processes. The Stirling engine is a very good example to apply the First Law of Thermodynamics to, as the amount of gas is fixed so the macro-variables are only pressure, temperature and volume. Simplifying the cycle makes it even easier for first time learners to understand how the engine works.

## P-V diagram simulation

This is an easy-to-use interactive simulation for P-V diagrams, created in GeoGebraTube (not by me!). Students will get to test themselves and familiarise themselves with making quick calculations for simple processes.