eli5: Why is it temperatures can go up to the trillions but only down to -273?
In: Physics
Because cold doesn’t exist. It’s just a lack of heat. Just like shadow is lack of light.
You’re confused because you’re using wrong scale, -273 Celcius is 0 Kelvin. And you can’t go below zero.
Cold isn’t equal to warmth. Warmth is the effect of moving molecules, whereas cold is the lack of movement. Similar to how there is no limit to how bright something can be, but dark is absolute because it’s just the absense of light, rather than its own thing. Cold is the absense of heat, and nothing else.
because water melts at 273.15 kelvin.
if you measure in Kelvin temp only goes up. it is a historical accident that Celsius scale was set to zero at water’s melting point.
For the same reason that the number of pies you eat in your life can never go below 0.
Temperature measures something. Every degree you go down, a little more of that something is taken away. At some point, there’s no more to take away.
That ‘something’ is a type of energy.
Why -273? Because a long time ago, somebody said “Tom ate 273 pies in his life. So, let’s measure how many pies you eat relative to Tom. If you eat more pies than Tom, that’s a positive number. If you eat fewer, it’s a negative number.”
Because degrees celsius or fahrenheit are not units of measurement like meter or second, they have an offset. 0m is the same as 0inch, and 2m is twice as long as 1m.
But 0°C is not the same temperature as 0°F, and 20°C is not twice as hot as 10°C.
The real 0 for temperature is 0 K or -273°C. The Kelvin unit does not have an offset.
So it just cannot get negative, just like mass or length, unless some meaning for this is defined. For length, for example, a negative value can mean that it extends in the opposite direction.
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