SP3 - Conservation of Energy Flashcards
SP3a
1) Where is chemical energy stored?
2) Where is kinetic energy stored?
3) Where is thermal energy stored?
4) Where is elastic potential energy stored?
5) Where is gravitational potential energy stored?
6) Where is nuclear energy stored?
1) Chemical energy is stored in food, fuel and batteries.
2) Kinetic energy is stored in moving objects.
3) Thermal energy is stored in hot objects.
4) Elastic potential energy is stored in stretched, squashed, or twisted materials.
5) Gravitational potential energy is energy stored in objects in high positions.
6) Nuclear energy is energy stored in atoms.
SP3a
1) What is the law of conservation of energy, and what is the units for energy?
2) How can energy be transferred?
3) What are the two types of diagrams that can be used to show energy stores and transfers and describe how they work?
1) Energy cannot be created or destroyed. It can only be transferred from one store to another. This is called the law of conservation of energy. The units for measuring energy are joules (J).
2) Energy can be transferred: by light, by heating, by sound, by electricity, and by forces.
3) A flow diagram uses boxes to show energy stores and arrows to show energy transfers.
A Sankey diagram shows the amount of energy transferred. The width of the arrows represent the amount of energy in joules.
SP3a
Describe energy store changes in:
1) An object projected upwards
2) Object projected up a slope
3) Moving object hitting an obstacle
1) In an object projected upwards, kinetic energy is transferred to gravitational potential energy, then vice versa as it falls back down.
2) In an object projected up a slope, kinetic energy is transferred to gravitational potential energy (and also by heat if friction is present).
3) In a moving object hitting an obstacle, kinetic energy is transferred by sound, by heat, and also kinetic energy is transferred to the obstacle if that moves as well.
SP3a
Describe energy store changes in:
1) Object being accelerated by a constant force
2) Vehicle slowing down
3) Boiling water in a kettle
1) In an object being accelerated by a constant force, the object is having work done to it, the work is converted into kinetic energy. Whatever supplies the force is having its energy transferred to kinetic energy.
2) When a vehicle is slowing down, kinetic energy is being transferred by heat (through brakes).
3) When boiling water in a kettle, energy is transferred by electricity into a store of thermal energy in the hot water.
SP3b
1) How is energy dissipated?
2) How can friction be reduced (to reduce waste energy)?
3) Why is energy wasted in machines (state 4 reasons)?
1) In mechanical processes (ie. when forces are involved on objects), energy transferred to it can cause a rise in temperature. This energy is dissipated (it spreads out into the surroundings), so it is wasted.
2) Friction between moving parts can be reduced by lubrication. Oil, other liquids, and sometimes even gases can be used as lubricants.
3) Machines waste energy due to:
- Friction between their moving parts
- Air resistance
- Electrical resistance
- Noise
SP3b
1) What is efficiency?
2) How can efficiency be measured?
3) What is the equation to calculate efficiency?
4) How can the efficiency of a device be increased (state 2 ways)?
1) Efficiency is a way of describing how good a machine is at transferring energy into useful forms.
2) The efficiency of a machine is measured using a number between 0 and 1. The higher the number, the more efficient the machine is. No machine can have the efficiency of 1 (be 100% efficient).
3) Efficiency = useful energy transferred by the device/ total energy supplied to the device
4) This can be done by reducing the amount of energy wasted, or recycling the waste output (finding another way to use the energy that would otherwise be wasted).
SP3c
1) What does insulation do?
2) How can energy be transferred by heating?
1) Insulation slows down the rate at which heat is transferred.
2) Energy can be transferred in heating through conduction, convection and radiation.
In conduction, vibrations are passed on between particles in a solid.
In convection, part of a fluid that is warmer than the rest rises and sets up a convection current.
Radiation is the only way in which energy can be transferred through a vacuum.
SP3d
1) What is gravitational potential energy?
2) How can it be calculated?
3) What is the gravitation field strength on Earth?
1) Gravitational potential energy (GPE) is energy that is stored because of an object’s position in a gravitational field.
2) The formula is: change in gravitational potential energy = mass(kg) x gravitational field strength (N/kg) x change in vertical height (m)
3) The gravitation field strength on earth is approximately 10 N/kg.
SP3d
1) What is kinetic energy?
2) What is the formula for kinetic energy?
1) Kinetic energy is energy stored in moving objects.
2) It is calculated using the following formula: 1/2 x mass (kg) x (speed)² (m/s)²
SP3e
1) State the different non-renewable energy resources
2) What is the definition of non-renewable?
3) What does burning fossil fuels do?
1) Non- renewable resources are nuclear fuels and fossil fuels: coal, oil and natural gas.
2) Non-renewable means that it will eventually run out and cannot easily be replaced.
3) Burning fossil fuels releases carbon dioxide and other gasses. Carbon dioxide emissions contribute to global warming.
SP3e
1) How is the use of non-renewable energy resources changing?
2) How were fossil fuels used during the industrial revolution (in the past)?
3) How is the use of renewable energy resources changing?
1) Most countries in the word are trying to cut down the use of fossil fuels. This will reduce pollution and also help to make supplies of fuels last longer. This also ensures that less carbon dioxide is being released into the atmosphere, which contributes to global warming.
2) During the industrial revolution, fossil fuels became an important source of energy as it was easy to mine, and provided a lot of energy.
3) Renewables are preferred because governments have agreed to cut down on their CO2 levels. New technology means that renewables are more efficient/ cheaper. Renewables reduces pollution, and ensures that less carbon dioxide and less of other greenhouse gases are being released into the environment.
SP3f
1) What are renewable energy resources?
2) List examples of renewable energy.
3) What are biofuels?
1) Renewable energy resources are energy resources that will not run out and can easily be replaced as they are used.
2) They include: solar energy, hydroelectricity, wind turbines, tidal power, geothermal and biofuels.
3) Biofuels are made from animal waste and plants. They are called carbon neutral, meaning that they release the same amount of energy that they took in form the atmosphere.
SP3f
What are the advantages and disadvantages of non-renewable resources (state 4 advantages and 4 disadvantages)?
Advantages
1. Costs to run fossil fuel extraction plants are cheaper than renewable energy plants
2. Fuel extraction costs are low
3. Fossil fuels are reliable
4. They are extracted at a rate fast enough to ensure that there is always some in stock
Disadvantages:
1. Burning fossil fuels releases carbon dioxide into the atmosphere, contributing to global warming
2. Oil spillages kill sea life and mammal living near the sea
3. Fossil fuels are slowly running out and are not easily replaced
4. Burning coal and oil also releases sulphur dioxide, which causes acid rain
SP3f
What are the advantages and disadvantages of generating energy from:
- Wind
- Solar
- Tidal
- Hydroelectricity?
Wind + Solar
Advantages: Low running costs, and does not produce pollutants.
Disadvantages: Energy generation depends on the weather, they take up a lot of space, they have a high upfront cost, and you can’t increase supply in times of peak demands.
Hydroelectricity + Tidal
Advantages: reliable, produces large amount of energy with no pollution, they work on large and small scales, hydroelectricity is able to produce a large amount of energy at short notice.
Disadvantages: they stop boats and fish from travelling up or down the river, the initial set up is expensive, it has negative effects on the surrounding environment.
SP3f
2) What are the different non-renewable energy resources used for?
2) What are the different renewable energy resources used for?
1) Fossil fuels are used for transport, heating, electricity generation. Nuclear fuels are used for electricity generation.
2) All the renewable energy resources are used for electricity generation, apart from geothermal energy which is used for heating and electricity generation.
