MIflyer
1st Lieutenant
"...if someone tells me it's 50ºF, I have no idea how hot or cold that is ... "
That is because it is neither.
That is because it is neither.
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Well not exactly...It is one or the other as soon as the reference temperature is statedThat is because it is neither.
Just asked google... it's 10ºC - that's cold."...if someone tells me it's 50ºF, I have no idea how hot or cold that is ... "
That is because it is neither.
That is a matter of opinion, there are 7.5 billion of them all maintain the same body temperature from the arctic to equator and for periods of up to 110 years.OK, so we're talking about the PHYSICAL sensation of hot and/or cold. The human skin does indeed have neurons that react not to heat but to heat LOSS and heat GAIN.
In the case you mentioned your temperature sensors were NOT reacting to the actual temperature but to the rapid loss of heat from your body as heat was carried away by the wind. That's why they post a "FEELS LIKE" temperature or "WIND CHIIL" generally speaking in the colder months.
One can easily go into hypothermia in 75F water due to the rapidity with which water conducts heat. In Vietnam during the monsoons it was easy to slip into hypothermia during +85F temperatures as wet clothing and wind carried heat rapidly from the body.
Those same neurons, like any other sensory organ can adapt to a continual sensory input (my house smells OK but yours stinks).
Put out three bowls of water one hot, one lukewarm, and the third cold water. Put one hand in the hot and the other in the cold. Let them adapt for 5 min or so. Now put both hands in the lukewarm water. To the hot hand it will feel cold and to the cold had it will feel hot.
Thermometers were developed BECAUSE of humans inability to sense actual temperatures
OK, so we're talking about the PHYSICAL sensation of hot and/or cold.
I thought it was metre only in France. My spell check prefers meter.
I thought it was metre only in France. My spell check prefers meter.
And that would be a US gallon which is smaller than an Imperial gallon.Yea, I've seen that mix in the bigger plastic bottles of pop though I tend to stick to the 2 L as they drop to 88 cents from time to time. Never seen the 1 L milk around here just gallon, 1/2 Gal and 1 qt
Gasoline by the gallon still
There is in a relative sense. If we have two bars of metal and (A) is at a temperature of 100F and bar (B) is at 90F then by all means scientific or non it is perfect correct to say that bar (A) is hot in comparison to bar (B). Like other relative terms HIGH -LOW; GOOd - BAD; TALL - SHORT they take meaning only with respect to each otherThere is no concept of 'HOT' in a scientific term
And that is a big NOPE. Human body temperature averages 98.6F/37C BUT that is a AVERAGE temperature and you may never have exactly that temperature or have in transiently at points during the day/night. Age, activity, external temperature, time of day cause temperature swings from 97F(36.1C) to 99F(37.2). Temps above 100.4F(38C) generally signal a fever which can rise to 102F(38.9) to 103F(39.4) in the normal course of the fever. 105F(40.5) and above signal a severe fever with potential brain damage.That is a matter of opinion, there are 7.5 billion of them all maintain the same body temperature from the arctic to equator
The fact is, that the human body is better at maintaining its temperature at a constant than the "constants" that the Celsius scale is based on. Water can exist at minus 40C under some conditions and at 20,000 ft water boils at 83 deg C. There is a variation in temperature with every person, but each person during a day is remarkably uniform to about 0.5C. Women have a greater variation with ovulation and pregnancy but again the variation is constant. seven and a half billon produced with this temperature control is remarkable.There is in a relative sense. If we have two bars of metal and (A) is at a temperature of 100F and bar (B) is at 90F then by all means scientific or non it is perfect correct to say that bar (A) is hot in comparison to bar (B). Like other relative terms HIGH -LOW; GOOd - BAD; TALL - SHORT they take meaning only with respect to each other
And that is a big NOPE. Human body temperature averages 98.6F/37C BUT that is a AVERAGE temperature and you may never have exactly that temperature or have in transiently at points during the day/night. Age, activity, external temperature, time of day cause temperature swings from 97F(36.1C) to 99F(37.2). Temps above 100.4F(38C) generally signal a fever which can rise to 102F(38.9) to 103F(39.4) in the normal course of the fever. 105F(40.5) and above signal a severe fever with potential brain damage.
During any and all of these gyrations those neurons that sense heat movement in and out of the body play no role whatsoever. On the body (axon) of these neurons are pores (ion channels) that can be opened (allowing an influx of ions) at specific temperatures. In 1997 a specific ion channel TRPV1 that opens at temperatures above 108F(42.2C) was discovered. As ions rush into the suddenly opened ion channel the change in potential causes the neuron to fire carrying the signal to the brain.
The actual "thermostat" of the body is a small portion of the brain known as the hypothalamus. Through its coordination of the autonomic nervous system it responds to external and internal stimuli to regulate body temperature. It regulates the activities of the skin, sweat glands, and blood vessels to regulate body temperature.
Sweating with the accompanying evaporation of water (an endothermic process) acts to remove heat from the body. An electric fan moves air (actually heating it a bit in the process) which increases the rate of evaporation or heat loss. Hence the sensing neurons report a cooling sensation. A metal plate and a piece of wood are at the same temperature but touching the metal (an excellent conductor of heat) it will feel cool while the wood (a non-conductor) will feel warm. The water for sweat is stored in the dermis (skin layer #2). When/if this layer becomes depleted sweating stops, evaporation ceases and body temperature rises rapidly. The term is heat stroke and can prove fatal
If it were only that simple. You missed: Roman mile, Italian mile, Arabic mile, Irish miles, English mile, Welsh mile, Scots mile, Irish mile, International mile, U.S. survey mile, Geographical mile, Metric mile, and Scandinavian mile
In 1754 Daniel Fahrenheit wished to exclude negative numbers since they made little sense,i.e. less than no temperature. In addition they were difficult to use correctly in mathematical formula. Therefore he made his zero the coldest temperature he could achieve at the time which was a concentrated salt, ammonium chloride, and ice mixture. His second fixed point was the blood temperature of a healthy man which he determined from a earlier temperature scale to be 90 on his new scale. He then adjusted his scale to make ice melt at 32 degrees and that put body temperature at 96. Using his new thermometer he found that water boiled at a constant temperature of 212 degree. After Anders Celsius published his metric temperature scale with fixed points at freezing/melting point of ice and boiling point of water the Royal Society fixed Fahrenheit's scale at the same points +32 degrees for the freezing point and 212 degrees for the boiling point. That gives the Fahrenheit scale 180 degrees between the two point rather than the 100 degrees on Celsius' scale and humans an oral temperature of a bit above 98 degrees
*meter
My Volt Ohm Metre uses Metric measurements..
The fact is, that the human body is better at maintaining its temperature at a constant than the "constants" that the Celsius scale is based on. Water can exist at minus 40C under some conditions and at 20,000 ft water boils at 83 deg C. There is a variation in temperature with every person, but each person during a day is remarkably uniform to about 0.5C. Women have a greater variation with ovulation and pregnancy but again the variation is constant. seven and a half billon produced with this temperature control is remarkable.
The international unit of measure is the metre and should be used globally (IMHO). In British English, a meter is a device used for measuring something (eg speedometer, gas meter, electric meter etc).
I read years ago the reason that the US and Imperial Gallon are different is that when the US first laid down its standards in the late 1700s Britain was using three different gallons so the Yanks took the most common and made it the US gallon. When the Brits later decided to have a standard gallon they (naturally) chose a different one.
Way back we had used the Queen Anne's gallon of 3.785l to measure wine. We also had different volumes and names to measure both beer and grain. When we realised that this was silly, in 1824, the UK chose a single imperial term and lumped together all three measurements, picking a roughly-average volume and calling it a gallon. American colonists, though, stuck to tradition and kept just the Queen Anne's volume for their own gallon definition.
In 1824, Britain adopted a close approximation to the ale gallon known as the imperial gallon and abolished all other gallons in favour of it. Inspired by the kilogram-litre relationship, the imperial gallon was based on the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury and at a temperature of 62 °F.
The whole concept of HOT or COLD is only about a physical sensation. There is no concept of 'HOT' in a scientific term