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| 184_notes:batteries [2020/08/20 16:33] – dmcpadden | 184_notes:batteries [2021/02/16 20:09] (current) – [Mechanical Model of a Battery] bartonmo |
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| Part of Section 18.4 in Matter and Interactions (4th edition) | Part of Section 18.4 in Matter and Interactions (4th edition) |
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| [[184_notes:q_in_wires|Next Page: Surface Charges around Circuits]] | /*[[184_notes:q_in_wires|Next Page: Surface Charges around Circuits]] |
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| [[184_notes:motiv_movingq|Previous Page: Motivation for Moving Charges]] | [[184_notes:motiv_movingq|Previous Page: Motivation for Moving Charges]]*/ |
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| ===== Batteries ===== | ===== Batteries ===== |
| {{youtube>yLagh-mh5dk?large}} | {{youtube>yLagh-mh5dk?large}} |
| ==== Chemical Model of a Battery ==== | ==== Chemical Model of a Battery ==== |
| [{{ 184_notes:chemicalbattery.png?200|Redox reaction represents a chemical model of a battery}}] | [{{ :184_notes:chemicalbattery_new.png?250|Redox reaction represents a chemical model of a battery}}] |
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| A battery is ultimately a chemical separation of charge. The battery consists of two metal plates placed in a salt solution: one metal produces excess negative charges when reacting with the salt solution (leaving the metal positive) and one metal produces negative charge in the salt solution leaving the metal positive. Chemically this is often referred to as a [[https://en.wikipedia.org/wiki/Redox|redox reaction]]. When connected by a conducting wire, the excess charges in the negative metal are able to flow to the positive metal, while a similar process happens with the salt solution. This is a very similar process to what occurs when you have two charged plates connected by a conducting wire; however, it takes much longer for the metal plates to become neutral. This means there is a (roughly) constant electron current between plates for some time. After a while, the plates are no longer able to react with the salt solution, which reduces the electron current and causes your battery to "die". | A battery is ultimately a chemical separation of charge. The battery consists of two metal plates placed in a salt solution: one metal produces excess negative charges when reacting with the salt solution (leaving the metal negative) and one metal produces negative charge in the salt solution leaving the metal positive. Chemically this is often referred to as a [[https://en.wikipedia.org/wiki/Redox|redox reaction]]. When connected by a conducting wire, the excess charges in the negative metal are able to flow to the positive metal, while a similar process happens with the salt solution. This is a very similar process to what occurs when you have two charged plates connected by a conducting wire; however, it takes much longer for the metal plates to become neutral. This means there is a (roughly) constant electron current between plates for some time. After a while, the plates are no longer able to react with the salt solution, which reduces the electron current and causes your battery to "die". |
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| This is of course a very rough explanation of a chemical battery. Many physicists and chemists are [[https://www.sciencedaily.com/news/matter_energy/batteries/|currently studying how to make batteries last longer and be more efficient]]. Applications of which include: spacecraft (where replacing batteries is not an option) and fuel cells (to power vehicles with only water as a by-product). | This is of course a very rough explanation of a chemical battery. Many physicists and chemists are [[https://www.sciencedaily.com/news/matter_energy/batteries/|currently studying how to make batteries last longer and be more efficient]]. Applications of which include: spacecraft (where replacing batteries is not an option) and fuel cells (to power vehicles with only water as a by-product). |
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| ==== Mechanical Model of a Battery ==== | ==== Mechanical Model of a Battery ==== |
| [{{ 184_notes:mechanicalbattery.png?200|Mechanical model of a battery}}] | [{{ 184_notes:mechanicalbattery.png?250|Mechanical model of a battery}}] |
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| Oftentimes in circuits, we are less concerned with how the electrons in circuits are produced and are more concerned with what happens to the charges after they are produced. This means we will generally simplify our model of the battery to what we call a "mechanical model" of the battery. In this model, the battery consists of two charged plates, one that is positive and one that is negative, with a conveyor belt that pulls the electrons from the positive plate to the negative plate. In this model, //the conveyor belt represents the chemical reaction in the battery that maintains the separation of charge//. | Oftentimes in circuits, we are less concerned with how the electrons in circuits are produced and are more concerned with what happens to the charges after they are produced. This means we will generally simplify our model of the battery to what we call a "mechanical model" of the battery. In this model, the battery consists of two charged plates, one that is positive and one that is negative, with a conveyor belt that pulls the electrons from the positive plate to the negative plate. In this model, //the conveyor belt represents the chemical reaction in the battery that maintains the separation of charge//. |