Combustion: A chemical reaction that occurs when a substance reacts with oxygen, releasing energy in the form of heat and light. This is an example of an exergonic reaction, just like speeding downhill on your bike.
Thermite Reaction: An extremely exothermic reaction between metal powders and metal oxides. It's like going downhill so fast on your bike that sparks fly off the wheels!
Cellular Respiration: The process by which cells break down glucose and other molecules from food in the presence of oxygen, releasing energy. This is another example of an exergonic reaction as it releases stored energy, much like coasting downhill on a bike.