Whether the world's population reached 7 billion people as of this past Monday is still in question, but the figure is close, if not over it. According to the running tally on Breathingearth, there are still about 50 thousand more births to go. More importantly, what does this look like when we try to explain it to our students? For most of them, the concept of understanding 7 billion people is writing out the number with a lot of zeros. Even though we can demonstrate this by having students compare the number 7 to 7,000,000,000 to see the difference, to them it is just a number. They have no real connection to it.
Knowing how large the population is today does not help them understand how we got there, nor does it explain why it continues to grow. An excellent visualization to help younger students grasp population size and the reason for its sustainability is the NPR video clip below, called Visualizing How a Population Grows to 7 Billion, by Adam Cole. It is a clear and creative demonstration using the concept of water in a glass to represent continents and countries over time. Liquid filling the glass symbolizes births and leaking from the glass signifies deaths. As advances in medicine and food production take hold, the leaks slow, and eventually births begin to outnumber deaths. This simple visual representation of population growth would fit into any history, math, or geography lesson.
