Exponential Growth Explained

You’d have to be living under a rock to have not heard the words exponential growth sometime this year.  Some may have already been familiar with the words.  For others like me, I’d heard them before but had never really cared about them.   In 2020 though, it’s important to know what they mean and how they relate to the coronavirus pandemic.

But what, precisely, is exponential growth?  Christian Yates who is the Senior Lecturer in Mathematical Biology at the University of Bath describes it this way:

‘The mathematical definition says that a quantity that increases with a rate proportional to its current size will grow exponentially. This means that as the quantity increases so does that rate at which it grows. The more infected people we have in the early stages of a disease outbreak, the more people they will infect and the more the cases will rise.’

To understand more about exponential growth you can watch these videos.

 

Investigation Time

In this investigation, your task is to see if you can make a graph that shows an exponential curve.    To begin with you could try creating a graph using the data below which shows how a coronavirus cluster can grow from one person to many.

Example data

Day 1	1
Day 4	3
Day 7	9
Day 10	27
Day 13	81
Day 16	243
Day 19	729

If using a tool like Excel to create your graph, try changing the type of graph so you can see what the curve looks like in different formats such as clustered column, line or stacked area graphs.