Measuring extremely high/low temperatures

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In summary, there are multiple ways to measure extreme temperatures ranging from 0K to 15 million K, including thermocouple thermometers, blackbody radiation, and optical pyrometers. The temperature of the sun can be calculated by examining its emission spectrum using Planck's Law for black body radiation. In addition, for temperatures close to absolute zero, a Bose statistic can be used based on the number of atoms in the ground state. These methods can be helpful in understanding the physical limits of temperature and can be used in introductory physics courses for self-teaching.
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dank
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I understand that the range of extreme temperature is from 0-15million K. What are the ways that we can measure this? How did they figure out the temperature of the sun?

thermocouple thermometer? blackbody radiation? optical pyrometer? I've tried searching for general information on these online but they usually take me to pages that sell thermometers and pyrometers.

I just registered because I'm taking an introductory online physics course where I have to teach myself basically. This looks like a great site which I will be reading very often to help myself get through physics. I'm pretty intimidated by this subject (and this forum!) because I have never taken a physics class and I'm having some issues already so any help would be greatly appreciated.

Thanks
 
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While the lowest possible temperature is absolute zero, I do not know of any existing upper temperature limit. Temperature is the average kinetic energy of the atoms/molecules making up whatever it is you're taking the temperature of after all. But physically speaking, there may be a limit where the energy is so high matter cannot exist as we know it (i.e. atoms).

This is probably not the only way, but the temperature of sun can be calculated by simply looking at its emission spectrum. Planck's Law for black body radiation should have the math needed. It says that any black body at any temperature will have a maximum emission at a specific wavelength. This wavelength gets smaller as the temperature increases. And if I have my facts right, the sun radiates most of its energy in the visible spectrum, peaking at around the green band.
 
  • #3
For temperatures approaching 0K, they use a Bose statistic which measures temperature based on the number of atoms in the ground state.
 
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thank you, i appreciate it
 

1. What is the range of temperatures that can be measured using scientific instruments?

Modern scientific instruments can measure temperatures ranging from -273.15°C (absolute zero) to over 100 million degrees Celsius, depending on the specific instrument and application.

2. How do scientists measure extremely high temperatures such as those found in the sun or nuclear reactors?

Scientists use specialized instruments such as pyrometers, spectrometers, and calorimeters to measure extremely high temperatures. These instruments use principles such as radiation, emission spectra, and thermal conductivity to accurately measure temperatures in these extreme environments.

3. Can extremely low temperatures be measured with the same instruments used for high temperatures?

No, extremely low temperatures require different instruments such as cryogenic thermometers and dilution refrigerators. These instruments use methods such as thermal expansion and superconductivity to accurately measure temperatures as low as 0.0001 degrees above absolute zero.

4. Are there any limitations to measuring extremely high/low temperatures?

Yes, there are limitations to measuring these temperatures. For extremely high temperatures, the instruments may be damaged or destroyed if they are not specifically designed for those temperatures. For extremely low temperatures, there is a limit to how close we can get to absolute zero, and there may be uncertainties in the measurements due to external factors such as heat transfer.

5. How do scientists convert between different temperature scales when measuring extreme temperatures?

Scientists use mathematical equations to convert between different temperature scales, such as Celsius, Fahrenheit, and Kelvin. These equations take into account the different reference points and unit sizes of each scale to accurately convert temperatures. However, for extremely high or low temperatures, specialized scales such as the Kelvin scale (which starts at absolute zero) may be used to avoid negative or extremely large numbers.

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