Topic 3 - Conservation of Energy Flashcards
SP3a - What are the 9 energy stores?
- Kinetic
- Thermal
- Gravitational Potential
- Elastic Potential
- Sound
- Light
- Chemical
- Nuclear
- Electrical
SP3a - By what processes can energy be transferred?
- Heating
- Forces
- Electricity
SP3a - What is the law of the conservation of energy?
- Energy cannot be created or destroyed, only transferred between stores.
- In a closed system, the total start energy = the total end energy
SP3a - What is unit for measuring energy?
Joules (J)
SP3a - What diagram might you use to display the transfer of energy?
A sankey diagram, The width of the bars represent the amount of energy.
SP3b - What is it called when energy transfers to its surroundings by heating?
Dissipation
SP3b - What might you do to moving parts to reduce enrgy loss and why?
- Use a lubricant.
- Moving parts cause friction which causes enrgy to dissipate losing energy.
- Lubrication reduces friction and thus energy loss by friction.
SP3b - What is the most common form of wasted energy?
Thermal
SP3b - How do you calculate efficiency?
total useful energy output / Total energy input Efficiency is on a scale of 0 to 1. To calculate it s a percentage, x100
SP3b - How do you distiguish useful and wasted energy on a sankey diagram?
The useful energy has an arrow going staright while the wasted energy arrow turns off.
SP3c - How is a convection current formed?
Part of a fluid (Liquid/gas) that is warmer than the rest rises up once it reaches the top it looses thermale enrgy and sinks back down. This forms a current.
SP3c - Why do cavities in walls help insulate a house?
- When thermal energy wants to travel it requires particles to travel throgh.
- It gives energy to these particles which causes heat.
- A cavity in the wall means that there is air in which particles will collide less and heat will pass through less, so heat can’t escape as easily.
SP3c - How is a flask able to maintain the temperature of its contents?
- Silver coating on the outside and inside reflects radiation which would transfer thermal energy
- Glass walls with vacuums between create a cavity stopping heat from entering or escaping
- Plastic stopper stops heat from escaping
SP3d - What is the formula for change in gravitational potential energy.
ΔGPE = m x Δh x g
(change in GPE is mass x change in height x gravitational field strength)
SP3d - What is the gravitational field strength on earth?
9.81 (Can be rounded to 10) m/s² or N/Kg
SP3d - What is the formula for Kinetic energy?
KE = ½ x m x v²
(Kinetic energy = mass x velocity² divided by 2)
SP3d - As an object falls describe the change in energy stores in terms of GPE and KE.
- As an object looses height, it looses GPE this ‘lost’ energy transfers, mostly, into kinetic energy as it is moving.
- Some other energy may transfer into sound energy
SP3e - What are the four main types of non-renewable energy sources?
- Fossil fuels:
- Natural gas
- Coal
- Oil
- Nuclear
SP3e - Apart from the lack of sustainability, why is burning fossil fuels not beneficial?
It releases Carbon dioxide and other gases that are harmful for the environment as they contribute to climate change.
SP3f - What are the pros and cons of using solar panels and solar energy?
Pros:
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Energy output depends on sun and so may not always be available
SP3f - What are the pros and cons of using wind turbines?
Pros:
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Many have to be installed and they have low output
- Takes up large spaces and soem say this spoils the view
- Not reliable
SP3f - What are the pros and cons of hydroelectric energy?
Pros:
- Very reliable
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Habitats destroyed
- Only useful when water sources are nearby
SP3f - What are the pros and cons of Tidal energy?
Pros:
- Extremely reliable
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Some argue that it harms wildlife
SP3f - What are the pros and cons of wave energy?
Pros:
- Reliable
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Small scale and experimental
- Low output
SP3f - What are the pros and cons of geothermal energy?
Pros:
- Will never run out
- Won’t release carbon dioxide once installed
- Extremely reliable
Cons:
- Only useful near volcanic sites
SP3f - What are the pros and cons of biofuel?
Pros:
- Will never run out
- Carbon neutral (Burning fuels releases carbon put planting plants took in carbon so its neutral)
- Useful as they can power vehicles
Cons:
- Can take up space that could be used for food, this can increase the price of food.
