Stellar Temperature Measurement

Do all the big words got you confused? Check out these sites for help.
or the
High-Energy Astrophysics Dictionary

Temperature Scales

There are several temperature scales in use today. One degree of temperature difference is not the same in the various scales, and which temperature is called zero degrees also varies. The two most widely used temperature scales for everyday use are the Fahrenheit and Celsius scales. A temperature scale that is used a lot in science (and astronomy in particular) is the Kelvin scale. These scales are described below:

Celsius scale

The Celsius scale was invented by the Swedish astronomer Anders Celsius (1701-1744, Sweden). It is fixed by two temperatures: zero degrees Celsius is the freezing temperature of water (at a standard sea-level air pressure), and a hundred degrees Celsius is the boiling temperature of water at the same pressure.
The zero point of the Celsius scale is practical, because below zero degrees Celsius you have to watch for ice on the roads and for frozen water pipes.
Zero degrees Celsius corresponds to 32 degrees Fahrenheit and 273.15 kelvin. A hundred degrees Celsius corresponds to 212 degrees Fahrenheit and to 373.15 kelvin. To change from degrees Fahrenheit to degrees Celsius, use this link: Temperature Conversion Calculator.

Fahrenheit scale

The Fahrenheit scale was invented by the German scientist Daniel Gabriel Fahrenheit (1686 Poland - 1736 Dutch Republic). It is fixed by two temperatures: zero degrees Fahrenheit was the temperature of a mix of water, ice, and salt. Ninety degrees Fahrenheit was what people in those days thought was the normal temperature of the human body.
These two fixed points on the Fahrenheit scale were perhaps not the most practical choices, because most people do not spend a lot of time trying to keep water fluid by adding salt to it, and we now know that the temperature that people then thought was the normal temperature of the human body was in fact a few degrees wrong.
Zero degrees Fahrenheit corresponds to about -17.8 degrees Celsius and about 255.4 kelvin. One hundred degrees Fahrenheit corresponds to about 37.8 degrees Celsius and to about 310.9 kelvin. To change from degrees Fahrenheit to degrees Celsius, use this link: Temperature Conversion Calculator.

Kelvin Scale

The Kelvin scale is named after the British scientist Lord Kelvin,
(William Thompson), Baron Kelvin of Largs. It is fixed by one temperature and a temperature difference: zero kelvin (don't say degree. kelvin and don't write kelvin with a capital K) is the lowest possible temperature, at which not even atoms move around anymore. A difference of one kelvin corresponds to a difference of one degree Celsius. This scale was invented by scientists for use in physics, because some formulas (those relating pressure of a gas to its temperature, or brightness to temperature, for instance) become easier if you use the zero point of the Kelvin scale. You'll notice that the formulas for the equilibrium temperatures above are also simpler when the Kelvin scale is used. The symbol for kelvin is K, so you can write 100 kelvin also as 100 K.

Zero kelvin corresponds to -273.15 degrees Celsius and to -459.67 degrees Fahrenheit. A temperature difference of one kelvin corresponds to a temperature difference of one degree Celsius, and 9/5 = 1.8 degree Fahrenheit. To change from degrees Fahrenheit to degrees Celsius, use this link: Temperature Conversion Calculator.

The National Institute of Standards and Technology (NIST) maintains databases for standardizing thermometers.

solar surfer iconsolar surfer icon
As you surf each web site listed below, look for information
about the questions listed directly below. At the quiz section,
you will be given an chance to check your learning.
right arrowWhat is the Kelvin Scale ?
right arrowWhat is the Celsius scale ?
right arrowWhat is the Fahrenheit scale ?
right arrowWhat is the temperature of sunspots ?

HOTsite 1 link iconHOT

click here to see the site

The Solar-Terrestrial Physics division of the National Geophysical Data Center is the focal point
for data pertaining to solar activity, the ionosphere, and geomagnetic variations.

HOTsite 2 link iconHOT

click here to see the site

NRL - Researchers in the Solar Physics Branch of the Naval Research Laboratory have been involved in observational and theoretical studies of the solar atmosphere since the early years of the space age. Experiments developed at NRL have flown on NASA missions such as Skylab/ATM, the OSO satellite series, the Space Shuttle STS-3, Spacelab-2 and Atlas missions.

Take The On-Line Quiz  prepared by Stanford Solar Center Here  HOT  site 3 link icon

Quicktake Sunspot quiz. On this page, bite-sized portions of some of the most fascinating aspects about the Sun, in the form of questions. Along the way, we point to sources for more information so that you can explore the topics on your own ( Stanford Solar Center) This site presents a collection of fun educational activities based on Solar Oscillations Investigation (SOI) and Solar and Heliospheric Observatory (SOHO) data.
Have a Solar Question?
Then ask a Solar Physicist !
HOTright arrow sun-question icon

Now.......Let's look at some HOT images of the sun
High Altitude Observatory
The Sun: a Pictorial Introduction
Welcome to the High Altitude Observatory, which is dedicated to the study of the Sun and of the response of the Earth's upper atmosphere to the Sun's output. As a National Science Foundation sponsored laboratory, the High Altitude Observatory is committed to the dissemination of its new knowledge to the community at large. by P. Charbonneau and O.R. White.
general facts about the Sun exploring temperature development thermometers thermal radiation & equilibrium temperature scales Hertzsprung-Russell Diagrams
Return to the Table of Contents
Return to Beginning

The Science Museum of Virginia
Mail comments, questions or suggestions to: Web Curators.

Copyright 1997
Regents of the University of California. All rights reserved.

This page last updated 06/25/02