The Thinks You Can Think!

Oh, the Thinks You Can Think: “How much water can 55 elephants drink?”

I got the idea for this blog while reading Dr. Seuss to my 1 ½ year old daughter. It’s really about conceptualizing units and quantities of water.

Suppose one elephant can drink 5 gallons of water in approximately 2 seconds. See this link:

https://thumbs.gfycat.com/HopefulHighAsiansmallclawedotter-small.gif

That’s 150 gallons per minute (gpm)!

By contrast, humans typically only drink 0.5 to 0.75 gallons per day. That is only 0.00035 to 0.0005 gallons per minute, or less than one-millionth the rate of elephant drinking. One elephant could drink 50 gallons in 20 seconds and 55 elephants would therefore drink 2,750 gallons of water in one sitting.

2,750 gallons is approximately 10,400 liters, 0.008 acre-feet, and 368 cubic feet. In the water industry in the United States, water is often quantified in terms of gallons, cubic feet and acre-feet. In Colorado and many western states, legal documents such as decrees list volumetric limits and flow rights in terms of acre-feet and cubic feet per second, respectively. For those not used to these units it can be quite difficult to get a sense for how much water that really is. I am hoping a little bit of nonsensical thinking about elephants can help make these units clear as mud.

How quickly could 55 elephants drain a swimming pool?

Suppose the swimming pool is a rectangular swimming pool 20 ft by 40 ft and 4 ft deep on average. This pool can hold about 3,200 cubic feet of water or approximately 24,000 gallons of water. Using the assumptions laid out above, we can calculate that 55 elephants, if they are thirsty enough, could drain the pool in in 174.5 seconds. Now assuming that they can only drink continuously for about 5 seconds at a time and take a 55 second break between drinking, it would realistically take these elephants just over a half hour to drain the pool.

“Oh, the thinks you can think if only you try” (Dr. Seuss, 1975).

Unit volume conversion table

Unit flow rate conversion table

Reference: Dr. Seuss. (1975). Oh, the Thinks You Can Think! Random House.