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Glossary of words for Energy
Glossary of words for Energy
Energy
Electrical
Chemical Potential
Kinetic
Potential Energy
Sound
Gravitational Potential
Nuclear
Elastic Potential
Solar (radiant)
Active Energy
Energy Transformations
Energy Conservation
Renewable alternatives
Transforming energy
Transferring energy
Joule
What is energy?
What is energy?
Energy is the ability to do work.
Energy gives us and everything else the ability to do things. For example when we throw a ball, cook on a barbecue, drive in a care or let off fireworks energy is involved.
Energy comes to us from the sun and is passed through food chains to all living things.
Types of energy
Types of energy
There are two types of energy- Potential energy and kinetic energy
Potential energy
Potential energy
Potential energy is stored energy, and energy from somethings height due to gravity. E.g. A ball sitting on a table has potential energy with respect to the floor because gravity acts upon it.
There is a range of different forms of potential energy:
Chemical energy- is energy stored in the bonding that holds particles together in substances, e.g. petrol.
Elastic energy- is the energy in stretched or compressed springy objects, e.g. a stretched rubber band.
Nuclear energy- is the energy in the nucleus or every atom that is released when the atom is split, e.g. in the production of nuclear power, energy released by fission and fusion.
Gravitational energy- is the energy an object had due to its height in a gravitational field, e.g. a rock on a hillside.
Kinetic energy
Kinetic energy
Kinetic energy is the energy of movement. It comes from the motion of waves, electrons and moving objects. E.g. A swinging pendulum has kinetic energy.
There is a range of different forms of kinetic energy:
Electrical energy- is from the movement of charged particles or electrons moving through a conduction or jumping through the air like a spark. e.g. lightning has electrical energy.
Radiant or light energy- is in visible light, X-rays, radio waves and other forms of what is called the electromagnetic spectrum. E.g. sunlight has radiant or light energy.
Thermal energy or heat- is the energy from the movement of particles making up a substance. The faster the movement, the greater the energy. E.g. a hot bath has thermal energy.
Motion energy- is the energy that a moving object has that makes it harder to stop or change direction. E.g. wind has motion energy
Sound energy- is the movement of energy through substances as a vibration. E.g. thunder has sound energy.
Kinetic energy is determined by the speed of an object and its mass. The faster it moves, the more kinetic energy it has. The greater the mass of a moving object, the more kinetic energy it has.
The magnetic field created by this bar magnet is shown using iron filings
Elastic potential energy
Energy transfers
Energy transfers
Energy can transfer or move from one store to another in different ways. Devices such as lamps and heaters may be involved, or processes such as combustion. For example, energy can be transferred:
by heating
mechanically
electrically
by radiation
Heating
Heating
Some objects are hotter than others. Energy is transferred from the hotter object to the cooler one, and the difference in temperature between them decreases.
Mechanical transfer
Mechanical transfer
Energy can be transferred mechanically through the movement of the parts in machines, and when the motion or position of an object changes. Sound waves and seismic waves (formed during earthquakes) are mechanical waves that transfer energy through materials and from place to place.
Electrical transfer
Electrical transfer
Energy is transferred when an electrical circuit is complete. A simple circuit may consist of a battery, lamp and wires. Internal energy stored in the battery is transferred to moving charged particles in the wire.
Transfer by radiation
Transfer by radiation
Visible light, infrared light, microwaves and radio waves are forms of radiation. They are carried by waves (although unlike sound, these are not mechanical waves and can travel through empty space). Electric lamps and burning fuels transfer visible and infrared light to the surroundings.
Other common transfers
Other common transfers
When an object falls the gravitational potential energy it possessed is converted to kinetic energy. When it has fallen half of the way down, half of the energy will have been transferred and so on.
Food contains internal energy stored in the bonds between particles. This is sometimes called chemical energy. This is converted into the energy all living organisms need during respiration. This conversion is similar to burning, for example wood. Here internal energy in the wood is converted into heat and light given out by the flames.
Energy transfer diagrams
Energy transfer diagrams
Energy transfer diagrams may be used to show the locations of energy stores and energy transfers.
For example, consider the energy transfers in this simple electrical circuit:
Conservation of energy
Conservation of energy
Total energy has the same value before and after a change .
The amount of energy stays the same.
Law of conservation of energy states that energy can be shifted from one form to another (transformed), or from one place to another in the same form (transferred), but the total amount doesn't change.
Examples of energy transformation:
Energy chains and efficiency
Energy chains and efficiency
What is an energy chain?
What is an energy chain?
An energy chain shows how energy is transferred from one object to another and transformed from one type to another in a given scenario.
Energy is measured in units called Joules or Kilo-joules and symbols are J and kJ respectively.
The change of energy from one object to another is never totally efficient. Some energy changes into forms that are not as useful. In food chains a lot of energy is lost as heat. In the same way, cars only change about 25% of the chemical potential energy in fuel into kinetic energy. The rest is given out as heat from the burning of the fuel and from the friction of the moving parts.
Producing energy in useful forms is the efficiency of an object, appliance or process.
For example:
If petrol with 100 J of chemical potential energy is used to run a car, only about 25 J of kinetic energy is produced.
Calculate the car's efficiency...
Energy sources
Energy sources
Worldwide we use a million billion kilo joules of energy every day, and this is increasing as the world's population and average energy consumption rise. Nearly all (90%) of this energy is supplies by burning fossil fuels like coal, oil and natural gas. These fuels can be used directly but are also burned to generate electricity.
There are two types of energy sources:
Renewable energy
Non renewable energy
What is renewable energy?
What is renewable energy?
Renewable energy resources are those that will not run out.
What is non-renewable energy?
What is non-renewable energy?
Non Renewable energy is energy which comes from sources that will run out or will not be replenished for thousands or even millions of years.
Types of renewable energy
Types of renewable energy
Wind power:
Wind power uses of wind to provide the mechanical power through wind turbines to turn electric generators
Wind turbines are sites in the windiest places, for example, on hilltops and on flat, open plains. Some are being built offshore to take advantage of the strong winds that blow over oceans.
Wind farms provide a limitless source of clean energy, but are expensive to maintain.
They are noisy and therefore cannot be sited near houses
Solar power:
Solar panels produce electricity directly from sunlight.
Unfortunately they are at their least efficient on cold wet days, when demand is at its highest.
Geothermal energy:
In geothermal energy production, heat stored in the Earth is used to heat water for use in electricity generation
This method of electricity production is at present limited to active geothermal areas, where the hot rock is near the surface.
Elsewhere it would prove to costly to dig to the depths needed to reach warm rock.
Tidal energy:
Tidal energy is the form of hydro power that converts the energy obtained from tides into electricity.
Turbines or floats that move as the tide comes in and goes out are very effective
However, they can only be used in strong tidal areas, which makes them expensive to maintain.
Hydroelectric power:
Hydroelectric power is a form of energy that harnesses the power of water in motion to generate electricity.
Most hydroelectric power is produced by building dams across rivers, and using the gravitational force of falling or flowing water to turn turbines.
NZ is fortunate in having many rivers suitable for generating hydroelectricity and much of our electricity is now generated in this way.
The cost for future hydroelectric projects is high, but they are clean and efficient.
The environmental impact of building dams has recently become a concern, as has the associated flooding of farmland.
Nuclear power:
Nuclear power is a clean and efficient way of boiling water to make steam, which turns turbines to produce electricity.
Nuclear power does not contribute to global warming however, people worry about accidents releasing radioactive and dangerous chemicals. The disposal of radioactive waste produced in nuclear power generation is also of concern.
Plant based fuels:
Plant or biomass is a source of sugars that can generate fuels by yeast of bacteria.
To produce significant amounts of biomass fuels requires large areas of land to be planted - this has to be weighed against other potential lang uses, such as farming and environmental concerns.
Types of non-renewable energy
Types of non-renewable energy
Fossil fuels coal, oil and gas are formed deep under ground from plant and animal remains that have only partly decomposed. Since these fuels takes thousands of years to form they are said to be non-renewable.
Coal
Coal-fired plants produce electricity by burning coal in a boiler to produce steam. The steam produced, under tremendous pressure, flows into a turbine, which spins a generator to create electricity. The steam is then cooled, condensed back into water and returned to the boiler to start the process over.
Oil
Oil can be burned in many ways to heat water and produce hot exhaust gases to create steam and spin a turbine to generate electricity.
Gas
The fuel gets burned and the boiler heats water which produces steam. This steam then turns the turbine to create electricity.
Electricity
Electricity
Electrical energy:
Electrical energy:
Electrical energy is required by all appliances (e.g. heaters, torches and Iphones). These appliances convert electrical energy to other forms of energy such as heat, light and sound.
Electricity
Electricity
Electricity is a very convenient form of energy because it can be readily generated, there is no time delay, and it can be easily converted into other forms of energy.
Electricity involves charged particles. They have either a positive or a negative electrical charge.
Normally objects and materials are uncharged- they have equal amounts of positive and negative charges.
Charge separation occurs when charge is transferred from one object to another. One object gains extra positive charge and the other extra negative charge. This occurs when you brush your hair and it stands up.
When charge separation has occurred it is possible to make electrical charge flow between the two objects. This is what we call an electrical current.
Conductors and Insulators
Conductors and Insulators
Metals are made of atoms whose electrons can roam freely. moving from atom to atom. Such substances are called conductors.
The free electrons of a conductor can be made to flow in a particular direction along the wire.
An electrical current is a flow of electrons along a conductor.
An electrical current will only occur when there is a difference in charge between the two ends of the conductor due to charge separation.
The atoms of other substances, such as plastic or glass, do not allow their electrons to travel freely from atom to atom. They are called insulators.
Electrical current
Electrical current
Electrical current occurs when electrons flow through a conductor from an area which is negatively charged to an area which is positively charged.
A circuit is a continuous pathway around which electrons can flow. A circuit is a conducting loop.
Components of a circuit:
A circuit needs an energy supplier- battery
An energy user- lamp
A complete conducting pathway- (wires) from supplier to user and back again
The metal wires used in a circuit are very good conductors and provide a huge number of free electrons which are able to travel around the circuit.
Electrical circuit
Electrical circuit
Drawing circuit diagrams
Drawing circuit diagrams
Scientists have developed a way of drawing electrical circuits to show the components involved and how they are connected. These diagrams are called circuit diagrams.
Each type of component has a special symbol but wires are shown by straights lines.
Series and Parallel circuits
Series and Parallel circuits
Types of circuits
There are two types of circuits:
Series and parallel circuits
Series Parallel
Series circuits
Series circuits
The components are connected end to end one after the other in a series circuit
They make a simple loop for the current to flow
If one bulb 'blows' it breaks the whole circuit and all the bulbs go out.
Parallel circuits
Parallel circuits
The components are connected side by side
The current has a choice of routes
If one bulb ‘blows’ there is still be a complete circuit to the other bulb so it stays alight.
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