Energy Flashcards
Explain how energy is conserved
Energy can neither be created nor destroyed- only converted from one form of energy to another
Examples of energy being moved between different stores
An electric kettle is used to heat water
What happens to wasted energy in energy transfers?
The wasted energy is dissipated into the surroundings
Explain ways of reducing unwanted energy transfers in mechanical processes
Reducing friction (lubrication from oil or other liquids)
Explain some ways in which energy is transferred wastefully by mechanical processes
When a machine gets hot
Define efficiency
Efficiency is a way of describing how good a machine is at transferring energy into useful forms
How can efficiency be increased?
Lubrication, thermal insulation, streamlining
What is the formula for calculating energy efficiency?
Efficiency= (useful energy transferred by the device)/(total energy supplied to the device)
Describe ways in which energy can be transferred by heating?
Conduction, convection, radiation, thermal conductivity
Describe ways of reducing unwanted energy transfers using thermal insulation
Double glazing, loft insulation, cavity wall insulation, fitted carpets, curtains, draft excluders
Define thermal conductivity
The ability of a material to conduct heat from its one side to the other
Describe the effects of the thickness and thermal conductivity of the walls of a building on its rate of cooling
the thicker the wall the smaller the rate of thermal conductivity
What are the different factors that affect the gravitational potential energy stored in an object?
Gravitational field strength, mass and height
What is the equation for GPE?
Change in GPE= mass x GFS x change in height
What are the different factors that affect the kinetic energy stored in an object?
Mass and speed
Kinetic energy formula
Kinetic energy= 0.5 x mass x (speed)^2
List non-renewable resources
Fossil fuels, natural gas, coal, steel, uranium, oil
How is use of non-renewable energy changing?
the use of non-renewable energy sources are being shut down as most countries are switching to renewable energy sources
List renewable energy resources
Solar, wind, hydro, tidal, geothermal, biomass
Explain why we cannot always use renewable resources
unreliable, not useful for increased demand
How is the use of renewable energy changing?
There is an increased shift from fossil fuels to renewable energy and more countries are investing more in renewable energy.
What are the advantages of using non-renewable energy sources?
Affordable, easy to produce, high in energy
What are the disadvantages of using non-renewable energy?
Produces greenhouse gases, can threat human health, will run out one day, contributes to climate change
What are the advantages of using renewable energy?
Less global warming, improved public health, more jobs and economic benefits
What are the disadvantages of using renewable energy?
Low efficiency, high upfront costs, limited storage capabilities, not available all the time, lots of land required to obtain energy from bio-fuels and solar farms
