We have discussed heat transfer and defined it to be the movement of heat. Heat can be transferred from one object to another, like the steak transferring heat to the plate, or heat can be transferred through an object, such as the baking a potato example. But, what is heat? We know we can feel heat. We can say it is a hot day, or the stove is hot, but that doesn't explain what heat is.
Heat is energy transferred between two objects because of a temperature difference between them. Heat always travels from hot to cold. So what is the difference between heat and temperature? Temperature is a measure of the energy, or heat, of something. It is a property that an object has based on the random motions of the particles in that substance. The faster that the molecules move, the higher the temperature and therefore the more heat transferred to a new object. Therefore, heat transfer is the movement of energy from something with high energy (a hot object) to something with low energy (a cold object).
When describing energy or temperature, we need a way to reference how much energy or how much temperature. Saying that it is a temperature of 20 outside does not tell us any information, just like saying a light bulb has an energy of 60. Sixty what? Fahrenheit is a unit of temperature. Other temperature units are degrees Celsius, Kelvin, and Rankine. Units that measure the same thing, such as temperature, can be converted from one to the other. See units. See conversions.
Heat transfer can occur three ways.
Heat lost/gained by an object
Units in the heat transfer equations
Proceed to Conduction
Proceed to Convection and Radiation
[Introduction | Kinetics | Heat Transfer | Mass Transfer | Bibliography]
This project was funded in part by the National Science Foundation and is advised by Dr. Masel and Dr. Blowers at the University of Illinois.
© 2007 Arizona Board of Regents for The University of Arizona
The three types of heat transfer methods are condution convection and radiation.
Photosynthesis
electrical energy into hat energy
exothermic!!
electrical energy into chemical energy
Your muscle energy converts to kinetic energy.
Potential energy to sound energy.
the kettle boils and then the energy comes out as steam
Mode of energy transfer in fluids is convection.
kinetic energy is transfered to electric energy
kinetic to electrical to sound
The basic idea is that electrical energy is converted into chemical energy, which is what the battery stores.
Input energy = output energy + losses