Conservation of energy GapFill

In any process, energy is conserved, meaning that energy  can be created and destroyedcannot be created or destroyedcan be destroyed but cannot be createdcan be created but cannot be destroyed. However, energy can be transferred between stores; for instance, when a ball is thrown straight up, its kinetic energy is converted into  stasisgravitygravitational potential energyweight, or when boiling a kettle, electrical energy is transferred to the  temperaturenon-electrical energymotionkinetic energy of the water particles.

If energy is transferred irreversibly in a way that we don't consider useful (often to thermal energy lost to the environment), we say that this energy has  been lostdissipatedbeen used upbeen destroyed. An example of this could be that when a stone is thrown against a rigid wall and it ‘bounces back’, some energy is transferred as  wasted energyinefficiencyan imprint on the wallsound and heat.

 EfficiencyPowerInsulationLubrication is a measure of how much energy has been transferred in a way we consider useful and can be calculated by useful energy transferred ÷ total energy transferred. If less energy has been transferred usefully than we'd like, there are a few ways we can reduce the wasted energy. If a moving part is dissipating energy because of friction,  distributioninsulationdissipationlubrication will cause more energy to be transferred usefully. If a heated building is losing a lot of thermal energy to its surroundings, the walls can be  lubricatedheated moredistributedinsulated.

The modern world depends on energy resources for a variety of applications, including electricity generation, transport and heating. Energy resources are categorised as either  replenishable or non-replenishablegood or badrenewable or non-renewablenew or old, based on whether or not there is a finite amount of a resource or whether more of the resource is produced continuously.

Some energy resources, such as  solar powerfossil fuelswind powernuclear power, give off a lot of by-products, and can contribute to pollution and climate change. Others don't have these same by-products, but might have other drawbacks, such as  their environmental impactbeing dependent on weather or locationbeing difficult to minethe type of electricity they generate. The amount of power generated in the UK from renewable sources has  increased a small amountdecreasedmore than doubledstayed the same between 2014 and 2021.