Collision Theory - GCSE Chemistry Definition

Collision Theory is a concept in chemistry that helps us understand how and why reactions happen. According to this theory, for a chemical reaction to occur, the reacting particles must collide with each other. However, not every collision leads to a reaction.

For a successful reaction, the particles need to collide with enough energy and in the right orientation. The energy needed for a successful collision is called the activation energy. If the particles collide with less energy than this, they simply bounce off each other without reacting.

By understanding Collision Theory, students can see why reactions happen faster at higher temperatures or when we increase the concentration or pressure, as these changes increase the chances of successful collisions.