What is Energy?
Look at the pictures and state the form of energy shown.
Inter-conversion of Energy
|
View the video and then answer the following questions:
1. What type of energy does the pencil possess when it held at a height? 2. What type of energy does the pencil possess when it is falling? 3. Where does the energy go after the pencil hit the bottom? 4. What is the law of conservation of energy? |
What is inter-conversion of energy?
In basic terms, this is the changing of energy from one form to another. For instance, energy may change from potential energy to kinetic energy and from kinetic energy back to potential energy. It is important to remember that energy simply can change forms leading to a conservation of energy.
Interconversion of mechanical energy and electrical energy
Mechanical energy can be converted to electrical energy by generators, and that the reverse, the conversion of electrical energy to mechanical energy, can be accomplished by motors.
Interconversion of chemical energy and electrical energy
A battery is a device that converts chemical energy to electrical energy. For some batteries this is a process than cannot be reversed, but for others it can. Batteries for which the process can be reversed are called rechargeable batteries. Fuel cells are similar to batteries in that they convert chemical energy to electrical energy. Fuel cells differ from batteries, however, in that the chemicals that are consumed by the fuel cell can be continually replaced while the device is in operation.
Interconversion of light energy and chemical energy
Most of us are familiar with devices that convert chemical energy to light energy, and that can convert light energy to chemical energy. Every living plant converts light energy, sunlight, to sources of chemical energy, typically sugars and starches by photosynthesis. It is the chemical energy thus produced, that provides us humans with the energy we need to stay alive. Yes; our diet consists exclusively of chemicals.
Interconversion of electrical energy and light energy
One type of electric light is the incandescent light bulb. In this device the light is produced indirectly. The electricity heats a wire, the filament, which glows “white” hot. An electric toaster or toaster-oven operates in the same way, but at a lower temperature, only “red” hot. Incandescent lights produce far more heat than light, and for that reason are said to be inefficient since the main purpose is to produce light. Another type of light is the fluorescent light tube. In this device the light is also produced indirectly. The electricity pops electrons out of the gas atoms in the tube, and as the electrons, now high in potential energy, fall back to their ground state their excess energy is emitted as photons of light. In a fluorescent light a larger fraction of the electrical energy is converted to light energy, and for this reason fluorescent lights are said to be more efficient than incandescent lights. Light energy can also be converted to electrical energy. In a “solar cell”, a photon of sunlight pops an electron up in energy, as in the photoelectric effect. These higher energy electrons can then be used to operate electrical devices.
Other interconversions of forms of energy
Almost any form of energy can be converted into another form of energy.
In basic terms, this is the changing of energy from one form to another. For instance, energy may change from potential energy to kinetic energy and from kinetic energy back to potential energy. It is important to remember that energy simply can change forms leading to a conservation of energy.
Interconversion of mechanical energy and electrical energy
Mechanical energy can be converted to electrical energy by generators, and that the reverse, the conversion of electrical energy to mechanical energy, can be accomplished by motors.
Interconversion of chemical energy and electrical energy
A battery is a device that converts chemical energy to electrical energy. For some batteries this is a process than cannot be reversed, but for others it can. Batteries for which the process can be reversed are called rechargeable batteries. Fuel cells are similar to batteries in that they convert chemical energy to electrical energy. Fuel cells differ from batteries, however, in that the chemicals that are consumed by the fuel cell can be continually replaced while the device is in operation.
Interconversion of light energy and chemical energy
Most of us are familiar with devices that convert chemical energy to light energy, and that can convert light energy to chemical energy. Every living plant converts light energy, sunlight, to sources of chemical energy, typically sugars and starches by photosynthesis. It is the chemical energy thus produced, that provides us humans with the energy we need to stay alive. Yes; our diet consists exclusively of chemicals.
Interconversion of electrical energy and light energy
One type of electric light is the incandescent light bulb. In this device the light is produced indirectly. The electricity heats a wire, the filament, which glows “white” hot. An electric toaster or toaster-oven operates in the same way, but at a lower temperature, only “red” hot. Incandescent lights produce far more heat than light, and for that reason are said to be inefficient since the main purpose is to produce light. Another type of light is the fluorescent light tube. In this device the light is also produced indirectly. The electricity pops electrons out of the gas atoms in the tube, and as the electrons, now high in potential energy, fall back to their ground state their excess energy is emitted as photons of light. In a fluorescent light a larger fraction of the electrical energy is converted to light energy, and for this reason fluorescent lights are said to be more efficient than incandescent lights. Light energy can also be converted to electrical energy. In a “solar cell”, a photon of sunlight pops an electron up in energy, as in the photoelectric effect. These higher energy electrons can then be used to operate electrical devices.
Other interconversions of forms of energy
Almost any form of energy can be converted into another form of energy.
Test the Law of conservation of energy
|
Try this experiment to see if you would get the same result.
|
Mass converting to energy
|
1. Compare nuclear fission and nuclear fusion.
|