Weekly Challenge 1: A Pound of Ants and the Capabilities of Intelligent Biomass

 Posted by DrJeff on May 26th, 2009

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This post is a Dr. Jeff’s Weekly Challenge and a Driving with Jordi.

A day late because of Memorial Day in the U.S.


I’m proud to post my first Driving with Jordi, so here we go!


Two weeks ago I was driving Jordi to school. We started down the road with 5 minutes of quiet contemplation, both of us just getting our heads wrapped around the new day, me with a cup of coffee in hand. Then, out of the blue came the question, “daddy, how many ants in a pound of ants?” I had to ask, “where did that come from?” So he explained that the day before he was hanging out in our big vegetable garden (he loves doing that), picked up a rock, and found lots of ants scurrying for cover. They were really small, and there were lots and lots of them. So he came up with this question to help him get a sense of their scale relative to a familiar ‘ruler’. He picked a pound. He came to me for the answer. I had no clue. So I decided to post this as part of this week’s challenge (see below.) You’ll be happy to know that I now have the answer and have already shared it with Jordi. But he promised not to tell.


Every time we drive together, his question launches a whole conversation. This time was no different. I remembered that in my presentations I sometimes liken the human race to a colony of ants scurrying around the surface of the planet. It’s a great teaching tool given kids know ants, and know ants are part of a ‘society’ in which each ant has a job.


So we talked about the human race as a colony of ants. We humans are all over the planet. We’re changing the environment on a global scale. I told Jordi about the term “biomass” which is the mass (equivalently the weight) of living things. You can imagine the biomass of all living things on the planet—the Earth’s biomass. You can also imagine the biomass of the entire human race. Surely with humanity’s ability to change the entire planet, its biomass must be huge!  Let’s see. Let’s make this the second part of your challenge this week, though this one is a little tougher (for, e.g., good for middle and high school students.)


Here now the challenge—


1.  How many ants in a pound of ants?

Hint: there is no single answer because there are lots of different species of ants. So do some research on ants, figure out an answer, and see if your answer falls in the range I’ll give you next week.


2.  How much does the human race weigh?

Hint: you’ll need to know how many humans are on the planet. Here you go, courtesy of the U.S. Census Bureau.


3. Wait, I hear Ellen in Detroit saying, “but Dr. Jeff, I’d rather know the total volume of the human race, in other words, how big a volume of space would you need to just fit the entire human race?” Good thinking Ellen! That’s another great way to look at it. So let’s make this a third part of the challenge. Once you calculate 2 above, figure out the total volume of the human race.


Hint: you can assume that we humans are made mostly of water, and every 1,000 kg of water takes up 1 cubic meter of space. For those of you who like to conceptualize using the English system of units, 1 ton of water (2,000 lbs) takes up 32 cubic feet of space.


Ok, get to work!


Answers are now posted here!


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One Response to “Weekly Challenge 1: A Pound of Ants and the Capabilities of Intelligent Biomass”

  1. steflong Says:
    May 26th, 2009 at 6:16 pm

    Thank you for the intellectual blog – thank you for the interesting questions – thank you for giving teachers something to use in their classrooms that is inspired by kids (and we know you’re a kid at heart 🙂 – THANK YOU, Dr. Jeff! I’ll be anxiously awaiting the answer next week, by the way.