The laws of thermodynamics
Systems and surroundings
- An open system can exchange both energy and matter with its surroundings. The stovetop example would be an open system, because heat and water vapor can be lost to the air.
- A closed system, on the other hand, can exchange only energy with its surroundings, not matter. If we put a very tightly fitting lid on the pot from the previous example, it would approximate a closed system.
- An isolated system is one that cannot exchange either matter or energy with its surroundings. A perfect isolated system is hard to come by, but an insulated drink cooler with a lid is conceptually similar to a true isolated system. The items inside can exchange energy with each other, which is why the drinks get cold and the ice melts a little, but they exchange very little energy (heat) with the outside environment.
The First Law of Thermodynamics
- Light bulbs transform electrical energy into light energy (radiant energy).
- One pool ball hits another, transferring kinetic energy and making the second ball move.
- Plants convert the energy of sunlight (radiant energy) into chemical energy stored in organic molecules.
- You are transforming chemical energy from your last snack into kinetic energy as you walk, breathe, and move your finger to scroll up and down this page.