Changes in Heat and Energy Diagrams - Video & Lesson Transcript | socialgamenews.info
David explains "work" as the way forces transfer energy to and from objects. Work and the work-energy principle Thermal energy from friction . Nine anxiety scores taken before and after counseling show the following differences ( before-. Work. Work = Force x “parallel distance”. (parallel component heat, sound, light , etc Work-Energy Relationship . therapy” following a poor practice. The Gases do expansion or compression work following the equation: Like heat, the energy change from work always occurs as part of a process: a system can do.
These changes from one phase to another are referred to as phase changes. Did you know that the temperature of water doesn't increase when it boils?
Work as the transfer of energy (video) | Khan Academy
The water's temperature increases up to boiling and then remains constant as it boils. We will use diagrams that illustrate the relationship between temperature and heat to explain how this works. Before we do that, however, we need to describe the relationship between temperature and heat. Let's discuss temperature first. You are likely familiar with temperature as it is a common topic of conversation.
We express temperature in degrees Fahrenheit, degrees Celsiusand even Kelvin, which is an absolute scale.
But, what is temperature? Temperature is a measure of how fast the molecules of a substance are moving. The faster the molecules move within the substance, the higher the temperature. For example, hot water molecules move faster than cold water molecules.
- Internal energy
- Work and energy
- Key Points:
Hot water molecules move faster than cold water molecules and create more energy. Temperature can be defined as the average kinetic energy of a substance, where energy is the ability to do work. Kinetic energy is energy of motion and thus reflects how fast an object is moving.
The faster the object moves, the more kinetic energy it contains.
The faster the molecules move that make up a substance, the greater the temperature of that substance. Now, let's talk about heat.
As substances are heated on a stove, in a microwave, or by the sun, energy is added to the substance. Heat can be defined as the total amount of energy contained within the substance. Where temperature reflects the average amount of kinetic energy, heat reflects the total energy.
For example, two liters of boiling water have the same temperature as one liter of boiling water. However, two liters contain more heat - that is, more total energy.
Heat and Temperature Are Related Now, let's consider the relationship between temperature and heat. A person lifting books from the ground to a shelf does work against gravity. A battery pushing electrical current through a circuit does work against resistance. A child pushing a box along the floor does work against friction. In thermodynamics, we are mainly interested in work done by expanding or compressing gases.
Work done by a gas Gases can do work through expansion or compression against a constant external pressure. Work done by gases is also sometimes called pressure-volume or PV work for reasons that will hopefully become more clear in this section!
Work/energy problem with friction
Let's consider gas contained in a piston. Wait, what is a piston?? Pistons are actually used in many mechanical applications all around us, such as inside a gasoline engine. I usually imagine a piston looking very similar to a bicycle tire pump, but here's some more information about what real pistons look like in case you are interested!
Here is a picture of the insides of a gasoline engine that shows two pistons side-by-side: A picture of a petrol-engine that has been cut in half to show the cross section of 2 side-by-side pistons. The piston on the left is arranged with a larger volume than the piston on the right. Schematic of a piston showing the movement of the piston head as the volume inside the piston changes.