A plasma is a state of matter that is formed when gas is heated to extremely high temperatures, causing the electrons to become separated from the atoms and creating a mixture of positively charged ions and negatively charged electrons.
Examples of hot plasmas include the sun, stars, lightning, and the interior of a fluorescent light bulb.
Examples of cold plasmas include neon signs, plasma televisions, and plasma jets used in medicine and industry.
Hot plasmas can reach temperatures of millions of degrees Celsius, such as in the core of the sun, while some laboratory plasmas can reach temperatures of over 100 million degrees Celsius.
In hot plasmas, temperature is measured using spectroscopy, which analyzes the light emitted by the plasma. In cold plasmas, temperature is measured using plasma diagnostic tools, such as probes or sensors.