The process of reduction of a compound's concentration over time. This can be through absorption, adsorption, degradation, dilution or transformation. In other words, attenuation is what leads to the decreasing intensity of energy as it passes through a medium. To envision this process, you must think of how different forms of energy such as heat, radiation, light, and heat travel in invisible streams. The degree of power that these energy forms have is measured through the matter that is propelling the energy. How the object that is hit reacts (stopping power) by these forms of energy is dependent upon the amount of force generated. The attenuation rate will measure the amount of energy that is consumed or averted from any given object.