In a well-known xkcd comic, Randall Munroe explains the Saturn V rocket in a diagram using only the ten-hundred most common words. (He says “ten-hundred” because “thousand” isn’t one of the thousand most common words.) And since “rocket” isn’t one of the ten-hundred most common words, the diagram is called “The Up-Goer Five.” The Up-Goer Five comic was so popular that Munroe made a whole book of such diagrams called The Thing Explainer. In it he explains such things as food-heating radio boxes (microwaves), the other worlds around the sun (the solar system), and the bags of stuff inside you (cells).

Munroe created a writing-checker to help other writers phrase things in the ten-hundred most common words. I’ve been experimenting with another writing-checker that was inspired by Munroe’s but is a little easier to use. This one was created by Theo Sanderson.

Here is my attempt to explain photosynthesis only using the ten-hundred most common words:


People and animals can eat. That is how they get the power they need to grow and move. A tree doesn’t eat. Other green growing things don’t eat either (except for a few green growing things that can catch flies and other small animals). But they do have power to grow, even though they can’t move. Green growing things get the power they need by turning light into food. The leaves (or other green parts) catch light. The bottom parts of the green growing things stick in the ground and get water. The parts that stick out of the ground get air. When the leaves catch light, the light somehow turns air and water into sweet stuff. The sweet stuff is food for the green growing thing. It is also food for people and animals. When green growing things turn light into food, they make power for themselves, but also for all the other living things that aren’t green.


You should try it. Pick a complex idea, explain it using the writing checker, and send me what you write.

The Up-Goer Five method of writing is instructive in a few different ways. On the one hand, it really exposes where one doesn’t know what one is talking about. I have a general sense of how photosynthesis works, but when I can’t hide behind words and phrases like chlorophyll, oxygen, and glucose molecule, I’m forced to reckon with the fact that I don’t really know what plants are up to. Is chlorophyll some kind of juice? Is it a molecule? Is it a receptor? A receptacle? A factory?

On the other hand—and this is just as important—the Up-Goer Five method reveals the extent to which we really do need big words if we’re going to talk about big ideas. The ten-hundred most common words just don’t cut it if you’re trying to explain how plants turn light into energy. It pains me to say this. I often encourage writers to dial down their diction, to stop showing off. But the real issue here is precision and clarity. Almost by definition, the most common words tend not to be the most precise words when we move beyond the realm of common knowledge and everyday experience.

As my Up-Goer Five account of photosynthesis demonstrates, “easy” words can actually be less clear than “hard” words. Unless you have less than a third-grader’s understanding of how plants work, I doubt you learned anything from my explanation of photosynthesis. I’m no botanist, but I could have done quite a bit better if I’d had a little more freedom of diction in my explanation.

I was first introduced to Randall Munroe’s Up-Goer Five comic through this episode of Seth Godin’s Akimbo podcast, or possibly the Q&A section in the second half of this episode, in which he answers questions about the previous episode. I’ll resist the temptation to summarize everything Godin says in those episodes. You can listen to them yourself, and I recommend that you do (they’re very short).

One of Godin’s most important ideas is this: Depth of understanding in a subject leads to a more nuanced vocabulary in that subject, but also, learning the vocabulary of a subject leads to a more nuanced understanding. You have probably heard that the Inuit people have something like a hundred words for snow. I’ve wondered if that’s really true, but as Godin points out, experienced skiers have dozens of words describing snow (powder, deep powder, spring powder, slush, corduroy, chop, ice, etc.), so why wouldn’t the Inuit have even more? I’ve only been skiing a couple of times, so much of the nuance is lost on me. I don’t know what the term corduroy means in the context of skiing, or why even such a term exists, but if I did, I would understand something new about skiing. In much the same way, when a child graduates from the 12-crayon box to the 64-crayon box, he is able to see colors he couldn’t see before.

Nobody likes a pedant—a person who uses big, unfamiliar words to inflate his own ego. But big, unfamiliar words can be a way to expand your reader’s horizons and give her new ways of making sense of the world. As is so often the case in writing, the principle at play is simply “Love your reader.”