**The Essential Exponential**

**"The greatest shortcoming of the human race is our
inability to understand the exponential function."**

- Dr. Albert A. Bartlett, emeritus Professor of Physics at the University of
Colorado at Boulder, USA.

**Rule of 70**

You can quickly estimate the length of time it would take for any given quantity
to double if it increases at a fixed rate. The doubling time is approximately
70 divided by the percentage rate.

**Doubling Time = 70 ÷ rate**

For example, if the population increases by 2% per year, then the total population
would double in 35 years.

## Understanding Exponential Growth

### Are humans smarter than yeast?

## Arithmetic, Population and Energy

Dr. Albert Bartlett has given his lecture over 1500 times since
1969.

Video 74 min