Chapter 2.2, Problem 2MI

Summary Introduction

To determine:

The definition of the term energy and Earth’s ultimate source of energy.

Explanation of Solution

The energy in the simpler terms can be described as the ability to do work. It exists in various forms such as kinetic, potential, electrical, thermal, chemical, nuclear, etc. On earth, the Sun is considered to be as the ultimate source of energy. The solar energy is used by the autotrophs such as plant to convert the inorganic molecules to useable organic molecules. These organic molecules are used by other organism to perform all the metabolic and physical processes.

The sun directly provides the solar energy which can be converted into electric energy by using solar cells. When the dead plants are buried in the soil, the heating of the ground due to the absorption of heat energy from the sun causes formation of fossil fuel under high pressure. The flow of wind is also due to difference in the heat of the atmosphere. In case, the sun does not provide the heat energy, all the water on earth would freeze and no hydro energy can be utilized. So, for any form of the energy present on earth, the sun is the ultimate source.