How many turkeys are consumed each year in the U.S. on Thanksgiving? And how many extraterrestrial civilizations might exist in the universe? Umm…wait…what?! Although these seem like unrelated questions, they’re really not. As we'll soon find out, they’re united by math.
My family and I cooked and consumed an entire turkey this week. We certainly weren’t alone in this endeavor/achievement since turkey is—for better or worse—the big cheese on most Thanksgiving menus. In our case, the turkey was rather delicious. As, of course, was the conversation with my delightful family.
At some point early on in the meal someone began pondering aloud about just how many turkeys must have met the same misfortune as our ill-fated fowl. While sort of a morbid thought to have while eating this particular meal, it’s nonetheless a good question.
Mid-way through the meal the conversation turned to the topic of intelligent life in the universe and whether or not it exists. The joke around the table was that the existence of intelligent life is debatable since we humans do a lot of things that might exclude us from the club. But all joking aside, humans are undoubtedly one example of intelligent life in the universe. The question is: Are there any others?
Both of these are very good and seemingly very unrelated questions. But they actually aren't entirely unrelated. Because it turns out we can use the same type of thinking to answer both. In particular, we can use a little logic and some simple math to make what physicists like to call “back-of-the-envelope” calculations and obtain approximate answers to each. Which is exactly what my family and I did this Thanksgiving. And it’s exactly what we’re going to learn how to do today.
Thanksgiving Day Turkey Math
According to statistics from the National Turkey Federation (which, by the way, is the same group that provides the president of the United States with a turkey to pardon each Thanksgiving—a particularly strange tradition given what everybody else is doing to them), around 212 million turkeys were consumed in the United States in 2015. This is, obviously, a lot of turkeys. But the question that I and my Thanksgiving companions had was how many of those 212 million birds were, shall we say, contributing to dinners around the country on this particular holiday (rather than just on any old day).
Around 212 million turkeys were consumed in the United States in 2015.
This kind of question seems tough to tackle. Of course, you could simply look up the answer (as we’ll see in a few minutes the National Turkey Federation will be happy to provide it to you)—but that’s not much fun. Instead, I and my intrepid family preferred to figure it out on our own by making a good old-fashioned back-of-the-envelope approximation! OK, I’m sure that some members of my family probably would have preferred the “look it up” approach; but they humored the rest of us and at least pretended to be amused by our quest.
Anyway, the best way to reason your way through a problem like this is to break it down into small pieces that can each be tackled easily. It’s important to not get too hung up on being overly precise along the way since high precision isn’t the goal here. In this case, we're just interested in a ballpark estimate—say to within 30%—of the total number of turkeys consumed on Thanksgiving. After all, we don't need to know the number down to the nearest turkey to learn about the magnitude of their contribution to the holiday.