In 1612 Santorio Santorio made the Thermometer, a Thermoscope would just show if some was hotter or colder, but the Thermometer would show the numbers and data.
Wouldn't it be cool if we could measure the thermoscope to scale with numbers?
112 Years Later in 1724, Daniel Gabriel Fahrenheit created the Fahrenheit Scale—that was used to record changes in temperature in an accurate fashion. It divided the freezing and boiling point of water.
So at 32 Degrees the water turns into ice and at 212 degrees the water starts to boil.
In 1848 Lord Kevin wanted to measure the extreme hot and extreme cold. He thought of the "Second Law of Thermodynamics", and developed the dynamical theory of heat. Later in the 19th Century scientists figured out what the coldest temperature is, it was 273 Degrees Celsius. This is known as the Kevin Scale.