Being in Act and Being in Potency

The most fundamental modality of being in act and being in potency is concerned not with movements or operations, but with the very substances of things as such. Each physical reality we encounter comes to be and can cease to be. If you do an experiment on a physical substance, you change its environment to see what potential activities you might cause. Let's take the phosphorus and make it emit radiation from potency to actuality. Such operations pass from existing in potency to existing in act.