Energy resources Flashcards
What is energy?
The potential to do work.
What is the principle of conservation of energy?
Energy cannot be created or destroyed, only transferred from one form to another.
What is the total energy in the universe?
It stays constant.
What is kinetic energy?
Energy of movement.
What is gravitational potential energy?
Energy related to anything about to fall or falling.
What is chemical energy?
Energy stored in fuels, food, batteries.
What is elastic energy?
Energy stored in elastic objects like rubber bands or trampolines.
What is magnetic energy?
Energy involving magnets.
What is electrostatic energy?
Energy related to electric charges.
What is nuclear energy?
Energy stored in the nucleus of atoms.
What is thermal energy?
Heat energy.
What is energy transfer?
How energy changes from one store to another.
How is energy transferred mechanically?
By moving parts or machinery, including energy transferred by friction.
How is energy transferred electrically?
Through wires.
How is energy transferred thermally?
By heating.
How is energy transferred by radiation?
As sound and light energy.
What unit is energy measured in?
Joules (J).
What is power?
The number of joules transferred every second.
What is the relationship between watts and joules?
1 Watt = 1 joule per second.
How is efficiency calculated?
(useful energy output / total energy input) x 100%.
What are all the energy stores?
Kinetic energy, GPE, chemical energy, elastic energy, magnetic energy, electrostatic energy, nuclear energy, thermal energy.
What are all the ways energy can be transferred?
Mechanically, electrically, thermally, radiation
What do Sankey diagrams represent?
Energy transfers
Sankey diagrams visually depict the flow of energy, showing both useful and wasted energy.
How is the size of each arrow in a Sankey diagram determined?
Proportional to the amount of energy it represents. Remember to label all arrows.
The width of the arrows corresponds to the quantity of energy transferred.
What do straight arrows in a Sankey diagram represent?
Useful energy transfers
Straight arrows indicate energy that is effectively utilized.
What do curved arrows in a Sankey diagram represent?
Wasted energy
Curved arrows indicate energy that is not effectively utilized.
What is conduction?
Transfer of thermal energy in solids or liquids by particle vibration
Conduction occurs when heat is transferred from hot regions to cold regions through direct contact.
How do molecules behave during conduction when heated?
Molecules vibrate more
Increased temperature causes molecules to gain kinetic energy and vibrate more vigorously.
What role do intermolecular forces play in conduction?
Allow adjacent molecules to vibrate
These forces enable the transfer of thermal energy from hotter to cooler areas.
What are conductors?
Materials that conduct thermal energy well
Conductors allow for the efficient transfer of heat.
What are insulators?
Materials that do not conduct thermal energy well
Insulators resist the transfer of heat, making them useful for preventing energy loss.
What are examples of good conductors?
Metals (e.g., copper, aluminum) and diamond
Metals have delocalised electrons that facilitate quick energy transfer.
What are examples of insulators?
Glass, rubber, plastic
These materials are commonly used to reduce heat transfer.
What is convection?
The transfer of molecules in liquids or gases by convection
Convection involves the movement of fluid due to temperature differences, resulting in the circulation of the fluid.
How do convection currents work?
- A heat source transfers thermal energy to the surrounding liquid or gas
- The liquid or gas heats up and expands
- It becomes less dense and rises
- Cold, dense liquid or gas falls to take its place
- The cycle repeats
This process creates a continuous loop of rising and sinking fluids.
What happens to a heated liquid or gas in convection?
It expands, moves further apart, becomes less dense, and rises
As the heated fluid rises, it creates a region of lower pressure that allows cooler fluid to move in.
What causes cold, dense liquid or gas to fall in convection?
It becomes denser as it cools and contracts
The cycle continues as the cooler fluid displaces the warmer fluid.
Give an example of convection in everyday life.
- Hot air balloons
- Boilers
- Temperature differences in houses
These examples illustrate how convection plays a role in heating and fluid movement in daily scenarios.
What is radiation?
The transfer of thermal energy by infrared radiation
Unlike convection, radiation does not require a medium for transfer.
What part of the electromagnetic spectrum does infrared radiation belong to?
Infrared radiation
Infrared radiation can travel through a vacuum and does not require a medium.
Which states of matter allow radiation to pass through best?
Gases allow radiation through better than liquids, and liquids better than solids
This property affects how heat is transferred through different materials.
What type of surfaces absorb and emit radiation the best?
Dark, dull surfaces
The color and texture of a surface significantly influence its thermal radiation properties.