Heat and Energy
Concepts of Heat and Temperature
Scope: Heat as energy; S.I. unit joule, 1 cal = 4.186 J exactly.
- Heat is a form of energy transfer between systems
- Temperature measures the average kinetic energy of particles
- Specific heat capacity determines how much energy is needed to change temperature
Anomalous Expansion of Water
Scope: Anomalous expansion of water, graphs showing variation of volume and density of water with temperature in the 0 to 10°C range. Hope's experiment and consequences of anomalous expansion.
- Water reaches maximum density at 4°C
- Expands when cooled below 4°C (unlike most substances)
- Critical for aquatic life survival in winter
Energy Flow and Its Importance
Scope: Understanding the flow of energy as linear and linking it with the laws of thermodynamics: 'energy is neither created nor destroyed' and 'no energy transfer is 100% efficient'.
- First Law: Conservation of energy
- Second Law: Energy tends to disperse (entropy increases)
- Energy quality degrades in conversions
Energy Sources
Scope: Solar, wind, water and nuclear energy (qualitative discussion). Renewable versus non-renewable sources.
Renewable Energy:
- Biogas, solar, wind, hydro, tidal
- Economic viability challenges
Non-renewable Energy:
- Coal, oil, natural gas
- Inequitable urban/rural distribution
Global Warming and Greenhouse Effect
Scope: Meaning, causes and impact on life on earth; projections for the future; what needs to be done.
- Greenhouse gases trap infrared radiation
- CO₂ levels have increased 50% since industrial revolution
- Potential impacts: sea level rise, extreme weather, ecosystem disruption
Energy Degradation
Scope: Meaning and examples of energy degradation.
- Energy becomes less useful as it transforms
- Example: Car engine loses energy as heat
- Related to the concept of entropy
Thermal Applications
Additional Concepts: Practical applications of heat and energy principles.
- Heat engines and refrigerators
- Thermal insulation techniques
- Phase change materials for energy storage
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