- Energy Unit
Energy: The ability to do work.
Potential Energy: stored energy that has not yet been used, such as energy stored in the oil in the furnace, the built-up electron charge on your clothes, or the rubber band that is fully stretched.
Kinetic Energy: When an object is moving. A faster-moving hammer has more kinetic energy when it hits a nail than a slower one. See the examples below.
Gravitational Potential Energy: When the potential energy is due to an object's position above the earth, such as how high a hammer is held, it is called gravitational potential energy.
Where does a roller coaster have the most potential and kinetic energy?
What are the potential and kinetic energy amounts at each level?
Thermal Energy: Thermal energy is the energy a substance or system has related to its temperature, i.e., the energy of moving or vibrating molecules.
Heat: Is the movement of thermal energy from hot to cold.
Temperature: is a measure of the average energy per molecule of a substance.
Energy Transformation: when energy changes from one type to another
Example: Potential Energy TRANSFORMS to Kinetic Energy as a roller coaster moves through the tracks.
Energy Transfer: when energy moves from one place to another. Energy moves from hot to cold. When you open a fridge the warm air around the fridge will move or TRANSFER to the cold air in the fridge.
Example: Energy is TRANSFERRED from a hammer to a nail.
Energy Efficiency: is the ratio of useful energy that is released to the total energy absorbed by the process.
Example: A car's engine transforms the chemical potential energy of gasoline into other types of energy. About 70% of the energy in the gasoline is released by heating, but only the remaining 30% is transformed into motion from the engine.
Types of Energy:
The Law of Conservation of Energy: This means that the total amount of energy before something happens must be equal to the amount afterwards, regardless of the process or energy types involved. The Law of Conservation of Energy doesn't say which kind of energy must be present before and after an event, just that the total energy doesn't change. Energy cannot be created of destroyed.
Conduction: is the process by which energy is transferred directly when materials touch each other. Conduction is a result of electron and atomic collisions inside the materials. Any solid, liquid or gas can transfer energy by conduction.
Examples of Conductors: Copper and aluminum
Insulation: Materials that are poor conductors and slow down the rate of energy movement
Examples of Insulators: Wood, wool, and paper
Electricity Generation: refers to any one of the several types of energy that is transformed into electricity.
Power Plant: distributes the electricity to the area around the plant.
Turbine: is like a large fan that uses mechanical energy to turn the blades.
Generator: transforms the rotating energy of the turbine into electricity.
Nonrenewable Resources: is a resource that has a limited supply; once it is used up there is no more of it. For example, coal, natural gas, and petroleum.
Fossil Fuels: Coal, petroleum, and natural gas. Fossil fuel efficiency is about 38-47%. A big problem is that it produces carbon dioxide, which contributes to global warming.
Nuclear Energy: when atoms of radioactive elements, such as uranium and plutonium are split apart, a huge amount of energy is release. The efficiency is about 35%. Plants can generate a lot of radioactive waste that can cause severe health and environmental problems.
Renewable Resources: is a resource that has a continuing supply, such as sunlight, water, wind, and biomass. To be considered renewable, a resource must be supplied faster than it is used up.
Tidal Energy: Captures the kinetic energy from the ocean water between high and low tides. The efficiency is about 90%
Hydroelectric Energy: Moving water turns the blades of turbines. It is done by transforming gravitational potential energy into electrical energy. It's efficiency can be nearly 95%.
Wind Energy: simply moving air, can turn the blades of turbines. They generate no pollution.
Solar Energy: Energy from the sun can be converted directly into electricity by solar cells. The efficiency is about 15%. We can collect solar energy using solar cells or photovoltaic cells.
Biomass: Some power plants can burn biomass, such as wood, paper, and organic material, and sometimes even garbage. The energy released by the burning is transformed into electricity. The efficiency is between 22-40%
Geothermal: this is the product of heat transferring from the interior of the earth to the surface. The efficiency is about 15%
Circuits: is any path along which electrical energy can TRANSFER (move from one place to another)
Series Circuit: Is one where all the components in the circuit are connected in succession with a battery. If one bulb goes out, they all go out. See the picture below:
Parallel Circuit:The components are set up in the circuit so that the electrical energy has more than one conducting path from the battery. If we unscrew one bulb, the other bulbs still stay lit.
As you can see from the chart, light bulbs are very inefficient, however if we had to select one light bulb to use that is the best, we should select CFL's or Compact Fluorescent light bulbs.
Calories: used as a measurement for energy.
Absorb or Absorption: light can be captured by an object and transformed into heat. The color black is good at absorbed light. Think about pavement in the summer time, it is very hot!
Transmit or Transmission: light can travel through the object and it is unaffected. Light can travel through glass. Clear film transmits light.
Reflect or Reflection: light can be bounced off of the surface of the object. Using a reflective film helps light bounce off of glass.
Additional Links to Help with Reviewing and Studying!
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