Energy And Energy Transfers Flashcards
What are the different energy stores?
Chemical - food, fuels, batteries
thermal - hot objects
kinetic - moving objects
gravitational potential - position in a gravitational field
elastic - changing shape, stretching, or squashing
What are the different energy transfer pathways?
Mechanically (transferring energy over a distance using a force).
• Heating (if there is a temperature difference, then heat will move from a hotter place to a colder place).
• Electrical (carried by moving electrons in an electric current).
• Radiation (such as lightwaves, radio waves and microwaves can be energy pathways).
What is the unit of energy?
Joules
When calculating energy requirements for various situations what do you have to consider?
diet and exercise
What is dissipation?
Dissipation is a term that is often used to describe ways in which energy is wasted. Any energy that is not transferred to useful energy stores is said to be wasted because it is lost to the surroundings.
What is the law of conservation of energy?
Energy can not be created or destroyed, only transferred.
Give an example to show that energy and temperature are different?
You can have a swimming pool and a beaker of water at exactly the same temperature.
Even though they are at the same temperature the swimming pool represents a much bigger thermal store of energy than the beaker of water.
How is energy transferred in conduction?
In conduction particles transfer energy by colliding with other particles when they vibrate.
Energy transfer happens until the two surfaces are at the same temperature. If you keep one surface warm by heating it then you will maintain the temperature difference. The solid will continue to conduct.
How is energy transferred in convection?
The part in contact with the heat source gets hotter. The particles move faster, causing them to become further apart, and a decrease in density. The hot part, then rises, and cooler, denser parts full and take its place at the bottom. They now heat, so the cycle continues. We call this a convection current.
What are some sources of infrared radiation?
Burning coal, the sun etc.
Everything emits radiation
How is energy transferred by radiation?
You don’t need particles to transfer energy by radiation. Light and infrared reach the Earth from the Sun by travelling through space.
Space is a vacuum. There are no particles in a vacuum.
How can an insulator reduce energy transfer?
An insulator is anything that isn’t good at conducting energy so it is slower at tranferfing heat so it slows down the speed at which energy is transferred.
What is the differnece between renewabke and non-renewable energy sources?
Non-renewable energy sources means that you can not easily get more of them when they run out.
However, renewable energy sources means that they will not run out.
What are the advantages and disadvantages of using renewable energy sources?
Renewable resources do not produce much carbon dioxide when they produce a current. However, they do produce carbon dioxide when they are being built.
What are the advantages and disadvantages of using non-renewable energy sources?
One problem with burning fossil fuels is that they produce a lot of carbon dioxide. Carbon dioxide is a greenhouse gas, so it can contribute to climate change. Burning fossil fuels also produce pollutants such as sulfur dioxide, nitrogen oxides, and particulates. They will also run out quickly if we use them too much.
Some advantages would be their capacity to generate huge amounts of electricity in just a single location and fossil fuels are very easy to find.
