What happens when you leave a hot cup of tea out for a while? In general, what happens when two substances at different temperatures come into contact with each other? What is happening on the microscopic level?

Today’s Purpose
Today we will be answering these questions by using a computer model to analyze the microscopic and macroscopic levels of thermal equilibration (the phenomenon of two substances at different temperatures moving to states of equal temperature).

Thinking in Levels
Computational scientists investigate complex systems on multiple levels using computer models. Without a computer model, it’s not possible to view multiple levels of a system at the same time. In this lesson, we will be considering two levels: the level of individual particles and the level of a group of particles. These are called the individual level and aggregate level.

Predictions
Let’s start by making a couple predictions about what will happen when two substances at different temperatures come into contact with each other.