Final answer:
The three primary temperature scales are Fahrenheit, Celsius, and Kelvin; Fahrenheit and Celsius have respective freezing and boiling points of water as references, whereas Kelvin starts at absolute zero. Conversions between the scales involve specific mathematical equations.
Step-by-step explanation:
The three most common temperature scales are Fahrenheit, Celsius, and Kelvin. The Fahrenheit and Celsius scales are relative temperature scales with the Fahrenheit scale using 32°F as the freezing point of water and 212°F as the boiling point. The Celsius scale uses 0°C as the freezing point and 100°C as the boiling point of water at standard atmospheric pressure. The Kelvin scale, on the other hand, is an absolute temperature scale starting at absolute zero, where 0 Kelvin is theoretically the lowest possible temperature where all kinetic motion of particles stops.
Temperature conversions between these scales can be performed using various equations. To convert from Celsius to Fahrenheit: (°C × 9/5) + 32 = °F. Conversely, to convert from Fahrenheit to Celsius: (°F - 32) × 5/9 = °C. As for Kelvin, converting from Celsius is direct by adding 273.15: °C + 273.15 = K. Thermometers measure temperature by using materials like mercury or alcohol, which expand or contract when heated or cooled, causing the visible liquid column to lengthen or shorten in response to temperature changes.