183_notes:internal_energy

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183_notes:internal_energy [2021/04/15 16:58] – [Systems With Structure Can Have Internal Energy] stumptyl183_notes:internal_energy [2021/06/02 22:49] (current) – [Internal Energy Can Take Different Forms] stumptyl
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 ==== Systems With Structure Can Have Internal Energy ==== ==== Systems With Structure Can Have Internal Energy ====
  
-[{{183_notes:mi3e_07-020.png?150|Two systems with different internal energies, but identical kinetic energies. }}]+[{{183_notes:week10_internalenergy1.png?150|Two systems with different internal energies, but identical kinetic energies. }}]
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 ==== Internal Energy Can Take Different Forms ==== ==== Internal Energy Can Take Different Forms ====
  
-{{ 183_notes:mi3e_07-021.png?150}} +{{ 183_notes:week10_internalenergy2.png?150}} 
-{{ 183_notes:mi3e_07-022.png?250}}+{{ 183_notes:week10_internalenergy3.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**.  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**. 
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 {{youtube>J__LrHm2-6g?large}} {{youtube>J__LrHm2-6g?large}}
  
-==== Quantifying Thermal Energy using Temperature ====+==== Quantifying Thermal Energy Using Temperature ====
  
 /* Left out part about thermometers */ /* Left out part about thermometers */
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 In the 1800s, [[http://en.wikipedia.org/wiki/James_Prescott_Joule|James Joule]] connected energy with temperature in [[http://en.wikipedia.org/wiki/James_Prescott_Joule#The_mechanical_equivalent_of_heat|his famous paddle wheel experiment]]. In his experiment, a rotating paddle wheel submerged in water was connected to a falling mass. Joule was able to measure the gravitational potential energy change associated with the falling mass and the temperature change of the water. In the 1800s, [[http://en.wikipedia.org/wiki/James_Prescott_Joule|James Joule]] connected energy with temperature in [[http://en.wikipedia.org/wiki/James_Prescott_Joule#The_mechanical_equivalent_of_heat|his famous paddle wheel experiment]]. In his experiment, a rotating paddle wheel submerged in water was connected to a falling mass. Joule was able to measure the gravitational potential energy change associated with the falling mass and the temperature change of the water.
  
-He discovered that it required 4.2 J to raise the temperature of a single gram of water by 1 Kelvin (1 K). This lead to the idea of //heat capacity//. The heat capacity of an object is the amount of energy needed to raise its temperature by 1 Kelvin. The //specific heat capacity// is a property of the material. It is the amount of energy needed to raise 1 gram of the material by 1 Kelvin. For example, the specific heat capacity of water (as measured by Joule) is 4.2 J per gram per Kelvin (4.2 J/K/g). For other materials, their specific heat capacities are different (e.g., 2.4 J/K/g for ethanol and 0.4 J/K/g for copper). Water has a very large specific heat capacity, so it requires a lot of energy to change its temperature.+He discovered that it required 4.2 J to raise the temperature of a single gram of water by 1 Kelvin (1 K). This lead to the idea of **heat capacity**. The heat capacity of an object is the amount of energy needed to raise its temperature by 1 Kelvin. The **specific heat capacity** is a property of the material. It is the amount of energy needed to raise 1 gram of the material by 1 Kelvin. For example, the specific heat capacity of water (as measured by Joule) is 4.2 J per gram per Kelvin (4.2 J/K/g). For other materials, their specific heat capacities are different (e.g., 2.4 J/K/g for ethanol and 0.4 J/K/g for copper). Water has a very large specific heat capacity, so it requires a lot of energy to change its temperature.
  
 The relationship between the thermal energy change of a material ($\Delta E_{thermal}$), the specific heat capacity ($C$), and the temperature change ($\Delta T$) is given by, The relationship between the thermal energy change of a material ($\Delta E_{thermal}$), the specific heat capacity ($C$), and the temperature change ($\Delta T$) is given by,
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