THERMODYNAMICS PRODUCTS Change of State of Gases Trainer Change of state of gases trainer (MTH-004) is a benchtop apparatus that demonstrates the relationship between pressure and volume of gas and also enables to study two changes of state of gases to be studied experimentally:Isothermal change of state (Boyle-Mariotte law).Isochoric change of state (Gay-Lussac’s 2nd law). For more information kindly Contact Us