Understanding Energy: Types, Sources, and Conservation

What is Energy?

Energy is the ability or property of bodies and physical systems to produce changes around them. During transformation, energy is exchanged through two mechanisms: work or heat. Energy is conserved and degraded in each transformation, losing the capacity to make further changes.

Thermal Energy or Heat

Thermal energy, or heat, is the energy exchanged between bodies with different temperatures. Heat is a form of energy transferred from one body to another as a consequence of the temperature difference between them.

Body temperature can be measured using the following scales:

• Celsius Scale: The fixed point 0 is the temperature at which water freezes, and point 100 is the temperature at which water begins to boil.
• Kelvin Scale: The fixed point 0 is the lowest temperature that can be achieved (-273°C), and each level has the same value as its corresponding Celsius scale.
• Fahrenheit Scale: Sets the freezing temperature of water at 32°F and the boiling point at 212°F.

Formulas

Mechanical Energy

Mechanical energy is the sum of potential energy and kinetic energy.

Gravitational Potential Energy

Gravitational potential energy is possessed by objects at a certain height.

Where:

• m = mass (kg)
• g = gravity (9.8 m/s²)
• h = height

Elastic Potential Energy

Elastic potential energy is the energy released when a compressed spring is released.

Where:

• k = spring constant
• x = length

Kinetic Energy

Kinetic energy is possessed by bodies in motion. Bodies gain energy by being accelerated by the action of forces.

Chemical Energy

Chemical energy is the energy associated with chemical reactions. In a chemical reaction, there may be outbursts of energy, or conversely, the chemical reaction may need energy to occur.

• Exothermic Reactions: Reactions that release energy in the form of heat, light, etc.
• Endothermic Reactions: Reactions that need to absorb energy from the exterior as heat, light, etc.

The Law of Conservation of Energy

"Energy is neither created nor destroyed; it only transforms."

Energy Sources

Energy sources are those that can generate energy, such as heat and light. There are two types of energy sources:

• Renewable or Inexhaustible: Their generation is continuous and relatively clean.
• Non-Renewable: Their reserves diminish as they are consumed, as there is insufficient time for their renewal.

Solar Energy

Solar energy comes from the sun and reaches the Earth as radiation. It can be harnessed through two systems:

• Direct conversion using photovoltaic or solar cells.
• Heat conversion using solar collectors.

Biomass

Biomass is organic matter produced by living organisms. This material is produced from plant products and their derivatives: crop and animal residues, forest residues, industrial waste, and urban organic food waste. Biomass can be used to obtain charcoal, biogas, and biofuels.

The Rule of Three R's

In industrialized countries, large quantities of waste are generated due to energy and material consumption. To reduce waste, follow the rule of three R's:

• Reduce
• Reuse
• Recycle