Differences

This shows you the differences between two versions of the page.

--- 183_notes:internal_energy [2014/10/29 21:26] – pwirving
+++ 183_notes:internal_energy [2015/10/09 20:36] – [Thermal Energy is due to Random Motion] caballero
@@ Line 2: / Line 2: @@
 Up to now, you have read about systems that have no internal structure: [[183_notes:point_particle|point particle systems]]. Even when considering a [[183_notes:energy_cons#multi-particle_systems|multi-particle system]], you have worked with uniquely identifiable objects. Now, you will read about the energy associated with systems that have some structure. Here, you will read about the connection between [[183_notes:define_energy|the concept of energy]] to [[183_notes:model_of_solids|the ball and spring model of the solid]]. This leads to the concept of thermal energy and how thermal energy is transferred into and out of systems.
+==== Lecture Video ====
+{{youtube>SYggxyY7XH8?large}}
 ==== Systems With Structure Can Have Internal Energy ====
-[{{ 183_notes:mi3e_07-020.jpg?250|Two systems with different internal energies, but identical kinetic energies.}}]
+[{{183_notes:mi3e_07-020.png?150|Two systems with different internal energies, but identical kinetic energies. }}]
 Until now, you have considered systems of point particles, which have no internal structure. You will now relax that condition.
@@ Line 15: / Line 19: @@
 === Internal energy can take different forms ===
-{{ 183_notes:mi3e_07-021.jpg?150}}
+{{ 183_notes:mi3e_07-021.png?150}}
-{{ 183_notes:mi3e_07-022.jpg?150}}
+{{ 183_notes:mi3e_07-022.png?250}}
 You have already seen one form of internal energy (i.e., when a spring is compressed). It can be useful to be able to unpack the different forms of internal energy to work on a particular problem of interest. An object that is rotating about its center of mass will have internal energy associated with rotation: //rotational energy//. While an object that is oscillating with respect to its center of mass will have energy due to vibrations: //vibrational energy//. When you eat food, you increase your internal energy in the form of //chemical energy//. A system whose temperature increases will increase its //thermal energy//.
-As you read previously, the total mass of the system is related to the system's total energy ($M_{sys} = E_{sys}/c^2$). This indicates that system's with more internal energy will have more mass. However, from a practical standpoint, the enormous rest mass energy associated with macroscopic system overshadows these contributions to the total energy meaning it only makes sense to worry about changes in internal energy whether they be rotational, vibrational, thermal, et cetera.
+As you [[183_notes:point_particle|read previously]], the total mass of the system is related to the system's total energy ($M_{sys} = E_{sys}/c^2$). This indicates that systems with more internal energy will have more mass. However, from a practical standpoint, the enormous rest mass energy associated with macroscopic system overshadows these contributions to the total energy meaning it only makes sense to worry about changes in internal energy whether they be rotational, vibrational, thermal, et cetera.
 The total internal energy of a system is given by the sum of all the possible forms of internal energy that the system can have,
 $$\mathrm{Internal\:energy} = E_{thermal} + E_{rotational} + E_{vibrational} + E_{chemical} + \dots $$
 ==== Thermal Energy is due to Random Motion ====
-In this section, we will focus on thermal energy. You have modeled atoms in a solid as single particles with connected by a spring. As you might have learned in your chemistry course, these atoms can have [[http://en.wikipedia.org/wiki/Rotational_transition|rotational states]] and [[http://en.wikipedia.org/wiki/Molecular_vibration|vibrational states]]. The internal energy associated with vibrational and rotational states does not increase the thermal energy (or temperature) of the solid material.
+In this section, we will focus on thermal energy. You have [[183_notes:model_of_solids|modeled atoms in a solid as single particles connected by a spring]]. As you might have learned in your chemistry course, these atoms can have [[http://en.wikipedia.org/wiki/Rotational_transition|rotational states]] and [[http://en.wikipedia.org/wiki/Molecular_vibration|vibrational states]]. The internal energy associated with vibrational and rotational states does not increase the thermal energy (or temperature) of the solid material.
+Thermal energy is associated with random motion of the atoms in the solid and is not recognized as collective behavior. It is distinct from the rotation and vibration of atoms as well. This random component of the internal energy is thermal and we associate it with the temperature of the solid. The higher the thermal energy of a particular solid, the more the atoms //jiggle// randomly, and the higher the temperature of that solid.((In fact, the temperature is related to both the energy and the [[http://en.wikipedia.org/wiki/Entropy|entropy of the system]]. In particular how the energy changes with entropy, but for now, you think of thermal energy as having a direct connection to the temperature of the solid.))
+==== Lecture Video ====
+{{youtube>J__LrHm2-6g?large}}
-Thermal energy is associated with random motion of the atoms in the solid and is not recognized as collective behavior. It is distinct form the rotation and vibration of atoms as well. This random component of the internal energy is thermal and we associate it with the temperature of the solid. The higher the thermal energy of a particular solid, the more the atoms //jiggle// randomly, and the higher the temperature of that solid.((In fact, the temperature is related to both the energy and the [[http://en.wikipedia.org/wiki/Entropy|entropy of the system]]. In particular how the energy changes with entropy, but for now, you think of thermal energy as having a direct connection to the temperature of the solid.))
 ==== Quantifying Thermal Energy using Temperature ====