Introduction to Energy and the First Law of Thermodynamics

Introductory Discussion and Definition of Energy

Classroom Management
- The instructor emphasizes the importance of clear communication and notes.
- The instructor notes that attendance might occasionally be affected by factors beyond their control, but they will strive to be present.
Defining Energy
- Student Contributions:
  - Anthony suggests energy is "something that gives power."
  - A student suggests "movement," specifically the movement of something within a system.
- Scientific and Textbook Definition: Energy is defined as the "ability to do work."
- Interconnectivity: To perform work, power is required. In the process of doing work, there is typically a change in location or some form of physical change.

Contextual Background and Devotional

Prior Knowledge Considerations:
- The instructor gauges student familiarity with energy from high school or previous university courses (e.g., at HCU).
- At least one student confirms prior experience with the topic.
Devotional Discussion: Defining Faith
- Multiple Choice Question:
  - A: Faith makes things easy.
  - B: Faith makes the impossible possible.
  - C: Faith removes all fear and doubt completely.
  - D: Faith guarantees you will always get exactly what you want.
- Discussion on Option C: Student Vivian notes that the word "completely" is the issue. Fear may still exist, but faith provides confidence in the midst of that fear.
- Discussion on Option A: The pathway to success is not always easy, even if one believes they will achieve an "A" in the class.
- Scriptural Reference: Mark 11:22–23. Jesus tells disciples to have faith in God and say to a mountain to be thrown into the sea.
- Theological Application: Faith must be accompanied by work, prayer, and fasting. It is the belief that the future can be better than the past.

The Principles of Energy Conservation and Transformation

The Fundamental Law
- First Law of Thermodynamics: Energy can never be created nor destroyed, but rather it can be transformed from one form to another.
- Importance: This is designated as a mandatory concept and a potential exam question.
The Primary Energy Equation
- The change of energy in a system is calculated by subtracting the energy exiting the system from the energy entering the system:
- $\Delta E = E_{in} - E_{out}$
- Total Energy In ( $E_{in}$ ): The total energy entering the system (e.g., calories from a can of soda).
- Total Energy Out ( $E_{out}$ ): The part of total energy used to perform physical work (e.g., walking from a dormitory to a classroom).
- System Equilibrium: In every closed system, total energy remains constant/conserved; it only changes its form or location.

Specific Types and Forms of Energy

Thermal Energy
- Relates directly to temperature changes within a substance.
- Molecular Action: Applying heat increases particle movement. For example, applying heat to liquid water can cause a phase change to gas (steam).
- Calculation Formula: $E_{thermal} = \rho \times V_{body} \times C_p \times \Delta T$
  - $\rho$ : Density of the substance.
  - $V_{body}$ : Volume/Body of the substance.
  - $C_p$ : Heat capacity (the quantity of heat a body is able to retain).
  - $\Delta T$ : Change in temperature (e.g., water boiling from $0\,^{\circ}\text{C}$ to $100\,^{\circ}\text{C}$ ).
Kinetic Energy
- Energy associated with covering distance or movement on the x-axis.
- Calculation Formula: $KE = \frac{1}{2} m v^2$
  - $m$ : Mass.
  - $v$ : Velocity (speed or the rate of change of distance with respect to time).
Potential Energy
- Energy associated with height or change along the y-axis.
- Context: Relevant when gravity affects movement (e.g., jumping from a top floor to the ground).
- Calculation Formula: $PE = m g h$
  - $m$ : Mass.
  - $g$ : Acceleration due to gravity (measured as $9.8\,m/s^2$ ).
  - $h$ : Height.
Electrical Energy
- The relationship between power and time.
- Calculation Formula: $E = P \times t$
  - $P$ : Power source/quantity of power.
  - $t$ : Given time (e.g., energy generated in one hour).
Mechanical Energy
- Involves work done by a force over a distance.
- Calculation Formula: $W = F \times d$
  - $F$ : Force.
  - $d$ : Distance.

Energy Conversion Processes and Real-World Examples

Fossil Fuel Power Plants
1. Chemical Energy: Stored in fossil fuels.
2. Combustion: Burning fuels creates a chemical reaction.
3. Thermal Energy: Heat creates steam and hot exhaust gases.
4. Mechanical Energy: Steam/gas turns a turbine.
5. Electrical Energy: The turbine generates electricity.
- Key takeaway: The energy is not destroyed; the chemical potential is simply converted to heat and then to mechanical/electrical forms.
Wind Power
1. Air Flow: Kinetic energy of wind.
2. Mechanical Energy: Pressure from wind turns the turbine blades.
3. Electrical Energy: The rotating turbine generates power for homes.
Solar Energy
1. Radiant Energy: Sun strikes semiconductor materials.
2. Electrical Energy: Light energy is converted directly into electricity.

Universal Energy Equation and System Boundaries

The Universal Equation
- $\Delta E = Q - W$
  - $Q$ : Total heat transfer or energy entering the system ( $E_{in}$ ).
  - $W$ : Amount of energy used to do physical/mechanical work (e.g., turning a turbine).
System Boundaries
- Defined as the surrounding area of the fluid or object under study.
- Example: If studying water in a kettle, the kettle walls represent the system boundary. Everything outside is the surrounding.

Questions & Discussion

Student Question (Hulu): Inquires about the nature of change in energy.
- Response: Change implies work is occurring. Every physical change results from energy converting forms.
Student Question (Module): Asks about "Energy Out."
- Response: Energy is not destroyed when it leaves as "out." It is simply converted to another form to perform a task. If studying the body, chemical energy (food) is converted to kinetic energy (walking), covering distance.
Student Identification: Students mentioned during the session include Anthony, Daniel, Matthias, Rodney, Tavy, Vivian, Ryan, and Rebecca.