Mathematical Modelling and Earth Day

Earth Day is April 22nd each year. To celebrate we made a few resources for you and your students to explore the world around us using mathematical models.


We can use scatterplot graphs to create our mathematical models using a linear equation. Here’s a short video explaining what these graphs are and how we use them. Including how to calculate slope, y-intercept, and the equation of the line. 


In order to answer our question we need to collect data, and that data comes in the form of variables. But what are the different types of variables and what do they mean?

Calculating the Slope of a Linear Model

In order to be able to use our mathematical model we need to be able to create an equation.

For a linear graph this is y = mx + b.

      • y: what we are looking for (response variable)
      • x: what we are looking at to find y (explanatory variable)
      • m: the slope of the line, where m = (y2 – y1)/(x2-x1); two points on our line of best fit (not two of our data points)
      • b: the y-intercept, or what y equals when x = 0 (need to find slope first to find this value)

We first start with the line of best fit (a line we either draw or use a program like Excel to help us find) that is as close to as many points as possible. We then choose our two points (x1, y1) and (x2, y2) from this line in order to find our slope (and equation) of our line.

You can also use Excel to find this equation as well if you ask Excel to show the equation of the line as a label.

Your Turn

Now it’s your turn! Go out in your community or search national databases to come up with a question that you can model and make predictions about our world and our impact on it!

Remember the 6 steps:

    1. Think of a topic
    2. Turn it into a question
    3. Gather data
    4. Build your model
    5. Explore results/make predictions
    6. Present your results

And then think of something you’d like to investigate. Here are some ideas:

      • Water usage vs # of household members
      • Neighbourhood greenspaces vs average building height
      • Changes in temperature vs time

If you find a good one to explore please  share it with us on Twitter @FieldsInstitute and @DrPamB