SP3 Conservation of Energy Flashcards
What is the law of conservation of energy?
Energy can be stored, transferred between stores, and dissipated, but it cana never be created or destroyed.
What are the 8 energy stores?
- Kinetic
- Thermal
- Chemical
- Gravitational Potential
- Elastic Potential
- Nuclear
- Magnetic
- Electrostatic
(King Timothee Came Galloping Enthusiastically Near Mount Etna)
What is kinetic energy?
Energy in a moving object
Kinetic energy (J) =
KE =
0.5 x Mass (kg) x Velocity ² (m/s) ²
0.5 x m x v²
What is thermal energy?
Energy in any object (more in a heated object)
What is chemical energy?
Anything that can release energy by a chemical reaction
What is gravitational potential energy?
Anything in a gravitational field.
Raised objects store energy in GPE stores.
The higher the object is lifted, the more energy is transferred to this store.
Δ Gravitational Potential Energy (J) =
Δ GPE =
Mass (kg) x Gravitational Field Strength (N/kg) x Δ Vertical Height (m)
m x g x Δh
What is elastic potential energy?
Anything stretched e.g. springs, rubber bands
What is nuclear energy?
Energy in the nucleus of an atom (aka atomic energy)
What is magnetic energy?
Energy between magnets of different poles
What is electrostatic energy?
E.g. two charges that attract and repel each other
What are the 4 energy transfers?
- Radiation
- Mechanical
- Electrical
- Heating
(Red Motorbikes Excite Humans)
What is radiation as an energy transfer?
Energy transferred by waves
What is mechanical as an energy transfer?
A force acting on an object and doing work
What is electrical as an energy transfer?
A charge doing work
What is heating as an energy transfer?
Energy transferred from a hot to cold object
Efficiency =
Useful energy transferred by the device (J) / Total energy supplied to the device (J)
Given as a number between 0 and 1
The higher the number, the more efficient the machine.
What are the 3 methods of heat trasnferal?
- Conduction
- Convection
- Radiation
What is conduction?
- Happens in solids
- Happens because of vibrations of particles due to heating
- The vibration moves along the material, moving the heat energy
What is convection?
- Happens in liquids and gases
- Hot material rises and spreads out
- This creates a cycle called a convection current
What is radiation?
- Doesn’t need particles (can travle through a vacuum)
- Is infrared rays
- Travels in straight lines
What is a conductor?
Material where heat and electricity can pass through easily
What is an insulator?
Material where heat and electricity can’t pass through easily
What is thermal conductivity?
A measure of how quickly energy is transferred via conduction through a material
What are thermal conductors?
Materials with high thermal conductivity
What are thermal insulators?
Materials with low thermal conductivity
What are non-renewable resources and some examples of them?
Resources that are not replenished, they will run out.
1. Nuclear fuels: Uranium, Plutonium
2. Fossil fuels: Coal, Oil, Natural Gas
What are renewable resources and some examples of them?
Resoucres that are replenished, they won’t run out.
1. Solar
2. Hydro-electricity
3. Wind Power
4. Tidal
5. Biofuels
What are the advantages of nuclear fuels?
- they are clean - produce no harmful gases
- reliable
- cheap
What are the disadvantages of nuclear fuels?
- radioactivity exposure is bad
- overall cost is high
What are the advantages of fossil fuels?
- readily available in large amounts
- reliable
- cost effective
- low running costs and fuel extraction costs
What are the disadvantages of fossil fuels?
- release carbon dioxide into the atmosphere, contributing to the greenhouse effect and global warming
- release sulfure dioxide - causes acid rain
- oil spillages - cause environmental problems
What are the advantages of solar cells?
- directly into electrical energy
- energy is free
- no pollution
- can be used in power stations
What are the disadvantages of solar cells?
- not available all the time
- initial costs are high
- small scale of energy generated
- only generates in daytime
What are the advantages of hydro-electricity?
- available at most time
- can be stopped and startted quickly unlike fossil fuel power stations
What are the disadvantages of hydro-electricity?
- impact on environment - possible loss of habitat
- inconvenient
- needs constant supply of water
- flooding
What are the advantages of wind power?
- can be used to generate a lot of electricity
- produces as much energy as fossil fuel power stations
- 70-85% of he time produces energy
What are the disadvantages of wind power?
- works as long as wind speed isn’t too fast/slow
- noisy
- a lot of turbines needed
- spoils landscape
What are the advantages of tidal power?
- reliable because we can predict when we can use them (happens twice a day)
- fuel cost is low
What are the disadvantages of tidal power?
- not available at all times
- not many places available in the UK
- may affectr birds/other wildlife
What are the advantages of biofuels?
- can be used from naturally available animal wastes, plants, waste woods
- reliable
What are the disadvantages of biofuels?
- can’t respond to immediate energy demands
- land is cleared for it - loss of habitat
- carbon dioxide emissions affect environment
