What is Energy? 💡

Energy is a fundamental physical quantity that represents what is needed from a natural process to accomplish a task. It can take many forms, including thermal, mechanical, electrical, and chemical energy. In the context of Earth science, energy is often discussed in relation to processes that shape and change the Earth, such as tectonic activity, weather and climate, and the cycling of elements through Earth's systems.

For example, the movement of Earth's tectonic plates is driven by the release of energy stored within the Earth's interior, which can manifest as earthquakes or volcanic eruptions. The Earth's climate is also influenced by the exchange of energy between the Earth and its environment, including the transfer of heat and light energy from the Sun. Finally, the cycling of elements such as carbon, nitrogen, and water through Earth's systems is driven by various forms of energy, including the energy of sunlight, which powers the process of photosynthesis in plants.

Overall, energy plays a central role in the study of Earth science, as it drives many of the processes that shape and change the planet.

In our fast paced society, we often hear the growing demand for energy to power our transportation, commercial and residential sectors. However, many individuals do not fully understand the concept of energy and the impact processing has on our environment. 

The concept of energy is complex as there are many forms that it takes place in and can be transformed. Therefore it is essential to be able to identify the two main categories of energy - Kinetic and Potential. 

Important to know- Potential energy can be converted into kinetic energy. 

Image Courtesy of Pixabay

Kinetic Energy

Kinetic energy refers to energy in moving objects. 

1. Radiant Energy ⇨ Light moves in waves

Example: Solar panels capture the light from the sun that moves towards us as light waves.

2. Thermal Energy ⇨ Heat is what causes movement of atoms or molecules 

Example: Biomass thermal energy captures energy from sources derived from the sun. As seen by the combustion of wood, the process of photosynthesis requires the sun. 

3. Mechanical Energy  ⇨ Movement of substances 

Example: Windmills convert the kinetic energy from the wind into mechanical energy through the rotation of its blade. 

4. Sound Energy ⇨ Movement in waves 

Example: A siren passing by emits sound waves of varying frequencies.

5. Electrical Energy ⇨ Movement of electrons 

Example: The Electrical power grid transmits electrical energy to consumers. 

Potential Energy

Potential energy refers to energy that is stored. 

1. Chemical Energy        ⇨ Stores within bonds that hold molecules together  Example: Incomplete combustion of methane CH4 releases energy. 

2. Nuclear Energy          ⇨ Stored within a nuclei of atom 

Example: Nuclear power plants generate electricity through atom fission 

3. Elastic Energy             ⇨ Stored in an object by applying force 

Example: Stretching a rubber band 

4. Gravitational Energy  ⇨ Stored by position

Example: A ball positioned at top of building 

Units of Energy 

Energy can be measured through a joule, calorie, a British thermal unit (BTU) or a kilowatt. Power is measured through a watt or horsepower. 

• Basic unit of energy → Joule (J)
• 1 gigajoule (GJ) =  1 Billion joules = 10^9 J
• 1 exajoule (EJ)  = 1 Billion GJ     = 10^18 J
• 1 Quad (only in US) = 1 quadrillion (1015) BTU (British thermal units) = 1.055 EJ 🎥 Watch: Environmental Science Streams