Editing 2073: Kilogram
Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.
The edit can be undone.
Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 8: | Line 8: | ||
==Explanation== | ==Explanation== | ||
+ | {{incomplete|Created by a CONSTANT PLANCK. Links to resources would be good. Explain motivation for characters' statements. Do NOT delete this tag too soon.}} | ||
− | Standard units such as the kilogram, meter, and second are redefined from time to time as measurement technologies improve. These redefinitions are generally done to improve the precision to which the various units can be known or reproduced, without changing their actual value. The joke here is that redefining the kilogram to equal one pound | + | Standard units such as the kilogram, meter, and second are redefined from time to time as measurement technologies improve. These redefinitions are generally done to improve the precision to which the various units can be known or reproduced, without changing their actual value. The joke here is that redefining the kilogram to equal one pound would not only fail to improve on its precision, but would also significantly change the value of what a kilogram is. |
− | + | On the day of this comic, the {{w|International Committee for Weights and Measures|International Committee for Weights and Measures}} voted to redefine the {{w|kilogram}} by fixing it to the value of {{w|Planck's Constant}}. This is done by passing a measured current through an electromagnet to exert a force to balance 1 kg. The change will take effect on May 20, 2019, when the platinum cylinder International Prototype Kilogram that defines the unit will be retired. This means that the mass of a kilogram will no longer be tied to a physical object, but to the fundamental properties of the universe. By fixing the value of Planck constant to 6.62607015×10<sup>-34</sup> kg⋅m<sup>2</sup>⋅s<sup>−1</sup>, the kilogram will be defined in terms of the second and the speed of light via the meter. | |
− | The | + | The previous method of confirming that a kilogram is accurate is to use physical metal weights measuring exactly one kilogram, periodically transporting them around the world to an official weight lab to confirm they still weigh the same. Over time these physical objects have changed very slightly in their mass making them unreliable in the long run -- thus running into the issue that a kilogram did not stay a constant measure of mass. Note that these weights and comparisons are so precise that a fingerprint on one of the weights could throw them off. |
− | + | In this comic, Black Hat announces that the kilogram has been redefined as equal to one {{w|Pound (mass)|pound}}. Ponytail and Cueball seem to think this makes things simpler, but Megan is alarmed. The metric system of measurement is the one used by most of the world and is the standard system used in science. Redefining the kilogram to be equal to the pound would be very disruptive and outrage supporters of the metric system. Redefining the kilogram as being a completely different size from before will create a lot of confusion, since now when people read a mass in kilograms they need to work out whether it was written in old kilograms or new (pound-sized) kilograms. | |
− | + | In real life, the pound is officially defined as 0.45359237 kilograms, or less than half a kilogram. This makes defining a kilogram as one pound even more impossible as they are then stuck in a loop, as the pound must weigh less than half of a kilogram, meaning the value of each would be equal to zero. | |
− | + | The title text continues the joke by saying that the meter has been defined as exactly three feet. The yard, the closest US measurement to the meter, is three feet. However, a meter is about 9 centimeters longer than a yard. As with the pound, the metric system is used to define the yard as it is officially defined as 0.9144 meters. | |
− | |||
− | The title text continues the joke by saying that the meter has been defined as exactly three feet. The yard, the closest US measurement to the meter, is three feet. However, a meter is about 9 centimeters | ||
==Transcript== | ==Transcript== | ||
Line 44: | Line 43: | ||
To expand on this even further, three additional universal constants that were previously measured and that had uncertainty values have been assigned fixed values, resulting in exact definitions of three corresponding units of measurement without affecting their applicability. Fixing the unit of elementary charge, ''e'', serves to define the unit of electric current, the Ampere. Fixing the unit of luminous efficacy ''K<sub>cd</sub>'' serves to define the unit of luminous intensity, the candela. And fixing the Avogadro constant ''N<sub>A</sub>'' serves to define the unit of amount of substance, the mole. | To expand on this even further, three additional universal constants that were previously measured and that had uncertainty values have been assigned fixed values, resulting in exact definitions of three corresponding units of measurement without affecting their applicability. Fixing the unit of elementary charge, ''e'', serves to define the unit of electric current, the Ampere. Fixing the unit of luminous efficacy ''K<sub>cd</sub>'' serves to define the unit of luminous intensity, the candela. And fixing the Avogadro constant ''N<sub>A</sub>'' serves to define the unit of amount of substance, the mole. | ||
− | A Wikipedia article about redefining the SI units of measure in terms of newly fixed values of things taken to be universal constants is {{w| | + | A very recent Wikipedia article about redefining the SI units of measure in terms of newly fixed values of things taken to be universal constants is {{w|Redefinition of SI base units}}. |
− | |||
− | |||
{{comic discussion}} | {{comic discussion}} |