A collision is an event in which two bodies exerts force on each other for a relatively short time.. Although the most common colloquial use of the word "collision" refers to incidents in which two or more objects collide, the scientific use of the word "collision" implies nothing about the magnitude of the forces.Some examples of physical interactions that scientists would consider collisions: An insect touches its antenna to the leaf of a plant. The antenna is said to collide with leaf.