In Part 1 I made the case that Amps are the electrical equivalent of a current of leaking Coke and Volts are the electrical equivalent of the pressure causing that Coke to leak. This was fascinating (I’m sure it was), but I ran out of time to address the original question: why did I nerd-cringe when I listened to this line from Marissa Meyers’ Archenemies?
Only the digital readings on its side indicated that amps were flowing through the system. Nova adjusted the dials, increasing the voltage.
Only the digital readings on its side indicated that amps were flowing through the system. Nova adjusted the dials, increasing the voltage.
Marissa Meyer, Archenemies, Cover Reveal
Well, the first reason has to do with persnicketiness on my part, but the second reason has to do with batteries.
Note that Marissa mentioned “amps flowing through the system.” This is fine – amps are the flow of electrons, so when Nova hooked her battery up to her box-dissolving setup, amps would indeed begin to flow. My cringe came at the last line:
Nova adjusted the dials, increasing the voltage.
In school, batteries are almost always a constant voltage source. This is because a battery is kind of like a shaken-up bottle of Pepsi – it has a given amount of pressure (read: voltage) that gives it the potential to create a flow of electrons. You can get a 1.5V battery (AA, AAA, D), a 9V battery (the lickable kind with both prongs on one side), a 3.7V battery (your typical phone battery), a 12V battery (like the one in your car), etc.
But the voltage of a battery is pretty much fixed by the chemistry. It drops slightly over time as you use up the charge in the battery, but you can no more “increase the voltage” in a battery than you can “increase the pressure” in a pressure vessel like a bottle of Pepsi or an air tank.*
*OK, you sort of can… keeping batteries warm will keep the chemical reaction happening correctly and sort of ‘increase the voltage’ relative to a cold depleted battery voltage. And they do sell ‘adjustable voltage batteries’ (e.g. for vaping), but these are really constant-voltage batteries with a circuit that sort of bleeds off some of the voltage available from the battery so you can use a lower voltage to drive your circuit (kind of like a pressure regulator on an air tank). So yes, Nova could technically have had a high voltage battery with a circuit that only provided low voltage at first, and she then turned the dials to allow more of the battery’s voltage to be available to her box-dissolving setup… so OK, I surrender, the quote from the book stands as feasible.
Before we abandon batteries, though, let’s look briefly at a common point of confusion: voltage does not tell you how powerful the battery is. For example, car batteries are 12V and are very powerful (you can even weld with them), but the little 12V batteries you can get for your car’s key fob are also 12V and are not very powerful.
Well, the first reason has to do with persnicketiness on my part, but the second reason has to do with batteries.
Note that Marissa mentioned “amps flowing through the system.” This is fine – amps are the flow of electrons, so when Nova hooked her battery up to her box-dissolving setup, amps would indeed begin to flow. My cringe came at the last line:
Nova adjusted the dials, increasing the voltage.
In school, batteries are almost always a constant voltage source. This is because a battery is kind of like a shaken-up bottle of Pepsi – it has a given amount of pressure (read: voltage) that gives it the potential to create a flow of electrons. You can get a 1.5V battery (AA, AAA, D), a 9V battery (the lickable kind with both prongs on one side), a 3.7V battery (your typical phone battery), a 12V battery (like the one in your car), etc.
But the voltage of a battery is pretty much fixed by the chemistry. It drops slightly over time as you use up the charge in the battery, but you can no more “increase the voltage” in a battery than you can “increase the pressure” in a pressure vessel like a bottle of Pepsi or an air tank.*
*OK, you sort of can… keeping batteries warm will keep the chemical reaction happening correctly and sort of ‘increase the voltage’ relative to a cold depleted battery voltage. And they do sell ‘adjustable voltage batteries’ (e.g. for vaping), but these are really constant-voltage batteries with a circuit that sort of bleeds off some of the voltage available from the battery so you can use a lower voltage to drive your circuit (kind of like a pressure regulator on an air tank). So yes, Nova could technically have had a high voltage battery with a circuit that only provided low voltage at first, and she then turned the dials to allow more of the battery’s voltage to be available to her box-dissolving setup… so OK, I surrender, the quote from the book stands as feasible.
Before we abandon batteries, though, let’s look briefly at a common point of confusion: voltage does not tell you how powerful the battery is. For example, car batteries are 12V and are very powerful (you can even weld with them), but the little 12V batteries you can get for your car’s key fob are also 12V and are not very powerful.
Images from Amazon, left and right
How can two batteries with the same voltage be so different? The answer is capacity. That 12V battery used for RVs or home backup power has 200Ah of capacity (a confusing unit for energy that can be converted to Joules), while the one used in the key fob has only 0.033Ah. You can think of these like two air tanks at the same pressure, except one is the size of a CO2 cartridge you’d put in your Airsoft gun and one is the size of the tank you’d see on a train car. They might have the same pressure, but one has much more energy than the other.
Alright, that’s enough for electricity. Until next time, read more fantasy.
How can two batteries with the same voltage be so different? The answer is capacity. That 12V battery used for RVs or home backup power has 200Ah of capacity (a confusing unit for energy that can be converted to Joules), while the one used in the key fob has only 0.033Ah. You can think of these like two air tanks at the same pressure, except one is the size of a CO2 cartridge you’d put in your Airsoft gun and one is the size of the tank you’d see on a train car. They might have the same pressure, but one has much more energy than the other.
Alright, that’s enough for electricity. Until next time, read more fantasy.