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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?

Video 8:28

Watch Video


Arithmetic, Population and Energy

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

Video 74 min

Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7 | Part 8

Newer Version - 66 min

Eat plenty of fruit and learn to multiply

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