Daniel Gabriel Fahrenheit, a Polish-born Dutch physicist, maker of scientific instruments, and inventor of the alcohol and mercury thermometers, developed the Fahrenheit temperature scale commonly used in the United States. Anders Celsius, a Swedish astronomer, developed the Celsius temperature scale, also called the centigrade scale, which is used in most countries and for scientific purposes worldwide. This book explores the path these men took to develop their respective temperature scales and provides readers with biographical information about their lives. The addition of STEM concepts helps readers understand the science behind the development of these temperature scales.