# Lesson 1 - Unit 4 Overview

A poet physicist once calculated how many atoms from Plato’s body each of us has appropriated as our own – probably in excess of 1010. Behind the vertigo of the multiple reincarnations and the comforting thought of all the great people each of has been lies the profound and fundamental principle of the conservation of mass.

Francois M.M. Morel

Having introduced the fundamental concepts on which the Contaminant Transport Module is based, we are now ready to discuss the use of the Contaminant Transport Module in detail, using a variety of Examples and Exercises so that you can learn in a “hands-on” manner.

We will start to do so in this Unit by walking through and describing a simple Example model.  As we shall see, this particular example model is not particularly complex, but does serve to provide a nice overview of the primary components (Species, Fluids, Solids and Pathways) that are used to build contaminant transport models in GoldSim. Note that we will not talk in detail about the elements that we will see in this model.  At this point, you don’t need to worry about those details. We will discuss those in subsequent Units.  Our goal here is to simply provide an overview of what a contaminant transport model looks like in GoldSim and to show the kinds of results it can produce.

Before doing so, however, in Lesson 2 we will explore exactly what the Contaminant Transport Module adds to the GoldSim user interface.

In Lesson 3 we will then describe the conceptual model of the system we will be simulating in GoldSim.

Lessons 4 through 10 then walk through the model in detail, describing the various components used to simulate the system.  The model is deterministic (i.e., not probabilistic).  Lesson 11 introduces a probabilistic version of the model in order to illustrate some key concepts associated with representing uncertainty in contaminant transport models.

This Unit has a total of 12 Lessons (including this overview and a summary at the end).