Energy Flashcards
What are the 8 main energy stores
magnetic thermal chemical kinetic electrostatic elastic potential gravitational potential nuclear
What is magnetic energy
The energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart.
What is thermal energy
The total kinetic and potential energy of the particles in an object, in most cases this is the vibrations – also known as the kinetic energy – of particles. In hotter objects, the particles have more internal energy and vibrate faster.
What is chemical energy
The energy stored in chemical bonds, such as those between molecules.
What is kinetic energy
The energy of a moving object.
What is electrostatic energy
The energy stored when repelling charges have been moved closer together or when attracting charges have been pulled further apart.
What is elastic potential energy
The energy stored when an object is stretched or squashed.
What is gravitational potential energy
The energy of an object at height.
What is Nuclear energy
The energy stored in the nucleus of an atom.
Examples of magnetic energy
Fridge magnets, compasses, maglev trains which use magnetic levitation.
Examples of thermal energy
Human bodies, hot coffees, stoves or hobs. Ice particles vibrate slower, but still have energy.
Examples of chemical energy
Foods, muscles, electrical cells.
Examples of kinetic energy
Runners, buses, comets.
Examples of electrostatic energy
charges have been pulled further apart. Thunderclouds, Van De Graaff generators
Examples of elastic potential energy
Drawn catapults, compressed springs, inflated balloons.
Examples of gravitational potential energy
Aeroplanes, kites, mugs on a table.
Examples of nuclear energy
Uranium nuclear power, nuclear reactors.
How to calculate efficiency
Efficiency=useful output energy/total input energy
How do you increase the efficiency of a device or a process
- Reducing the amount of wasted energy – With mechanical processes you need to reduce friction and find ways to ensure all of the fuel is going into an engine
What is insulation
Insulation slows down the rate at which energy is transferred out of a house by heating
What is conduction
In conduction vibrations are passed on between particles in a solid. Metals are good conductors
What is convection
In convection part of a fluid that is warmer than the rest rises and sets up a convection current
What is radiation
Radiation is the only way which energy can be transferred through a vacuum. Infrared radiation can also pass through gases and some solid materials. Infrared radiation is absorbed and emitted easily by dull, dark surfaces and is absorbed and emitted poorly by light, shiny surfaces.
A vacuum flask is a good insulator because…
shiny surfaces reduce radiation and the vacuum does not allow any heat to pass through except radiation. The plastic spacer and stopper are good insulators because they do not conduct heat keeping the inside at the same temperature.
What is the rate of which thermal energy is transferred called
Thermal conductivity
What does low thermal conductivity mean
The material is a good insulator
What are trapped air convection currents not able to form
So good insulators such as straw and aerogel due to lots of air spaces
Equation of change in gravitational potential energy
Change of gravitational potential energy = mass x gravitational field strength x change in vertical height
(GPE=mgh)
Equation for kinetic energy
Ke = 1/2 x m x v^2
What is non renewable energy
Resource that will run out because it cannot be renewed
e.g coal, oil, fuel, nuclear gas
Advantages of non renewable energy
- Energy dense stores
- Reliable
- Easily stored and transported
Disadvantages of non renewable energy
- Environmental impact of mining extraction of fuel
- Fossil fuels release carbon dioxide –> global warming, climate change, release sulphur dioxide = acid rain
- Soot / particulates = breathing problems ie asthma
- Non being replaced
7 renewable energy sources
Solar, Hydroelectricity, Wind turbines, Tidal power, Bio-fuels, Waves and Geothermal
