18 complicated scientific ideas explained simply

&quot;Now, explain it to me â€” like I&#039;m a 4-year-old.&quot;

(Image credit: ThinkStock/iStockphoto)

last updated 8 January 2015

A few months ago, Randall Munroe of the webcomic xkcd published a description of the Saturn V rocket using only the 1,000 most frequent words in English. Under this restriction, the rocket was called "up-goer five," the command module was "people box," and the liquid hydrogen feed line was "thing that lets in cold wet air to burn." The comic inspired Theo Anderson, a geneticist who supports accessible science education, to build a text editor that would force the user to write with only the 1,000 most frequent words. He then invited scientists to describe what they do using the editor.

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"Computers are used to share pictures, words, and movies (usually of cats) with other computers. The computers need to show the cats on boxes with tiny lights in them, but don't know how. People like me tell the computer many words so that it knows how to change the tiny lights to look like a cat. We try to make the lights change very fast so that you don't have to wait for your cats. Some days the lights are all wrong, and we have to tell the computer more words to make them look like cats again." Brandon Jones, Google Chrome GPU Team

"Deep inside our world is a huge ball of hot stuff. This is the stuff that turns the black rock we use to find our way when we go far away. I used to study tiny bits of the same black rock, inside real rocks, to know the pull of the deep hot under world ball long, long ago — before people, or animals, or trees, or almost any living things were here. I studied bits of the black rock, like the pieces we use to find our way, inside other rocks that formed in fire under the ground. The hot under ground ball gave these black rock pieces a direction long ago, and they did not forget." Peter Selkin, paleo/rock-magnetist

"I look at how water from the sky reaches the ground when there are trees in the way. Especially trees that are burned or dying. I try to figure out if the trees change: (1) how much water gets to the ground, and (2) what happens to the water when it's on the ground. I also try to figure out what will happen to this water in the next tens of years. This is important for things growing on the ground and living in the water, and for the water we use and drink." Sarah Boon, environmental scientist

"I tell space buses on a big, cold red rock in space to take pictures of the rocks and the sky. I look at the small rocks that go around the big red rock. The small rocks tell us about what it is like inside the big red rock. I like to look for ice water in the sky. I also take pictures of the Sun to learn about how much ice water and other stuff is in the sky. My favorite thing to do with the space buses is look at the stars in the night sky to look for ice water in the sky." Keri Bean, planetary scientist

"I look at how numbers play with other words when we speak. I think a lot about the way we mark words (like marking 'eats' different from 'eat'), and what that tells us about what they mean, and what other words around them mean (I show that it tells a lot). I also think a lot about whether the things we say allow more than one meaning. Like if someone says 'twenty boys ate a hot dog,' if it means they all shared one hot dog or if it means each one ate a hot dog, or if it means both." Sarah Ouwayda, linguist (syntax, semantics, Arabic, Semitic languages)

"There are bad people who want to make the things you see on the computer go away. Sometimes it is for money and sometimes it is a game. The simple way of making computer stuff go away is like shouting very loud so no one can hear. This makes it so you can not see the things on the computer you want until they stop shouting. I try to make them be quiet." Christian Ternus, information security researcher

"If we want to know how the brain makes memory and uses memory, we need to make people do things like learn stuff and then remember it. I want to know how we imagine things, and how memory makes this possible. So, I ask people to imagine things, and see how good they are with different words. Then, we look at their brains at work using a big noise box that takes pictures inside the head. We also ask people who are missing a piece of brain to also do stuff to see what they can and can't do. Then we'll know what different brain pieces do, and one day put all the pieces together to understand the mind." Kristoffer Romero, PhD student at the University of Toronto

"So imagine this. You are holding a bright thing and pushed by a friend so hard for so long that it seems to her that you are nearly as fast as the light leaving the bright thing. To her, the light is moving just a little bit faster than you, so only getting away from you slowly. But to you, the light is still moving away from you faster than anything else can ever move. You and your friend don't agree on how quickly you and the light are moving away from each other. What's going on?" Euan

"Our body doesn't like to have visits from other things that don't look like friends. When they come inside us, our cells look at them with many different types of eyes. Different eyes see different figures and forms, so they can find out what they are and what to do with them. They are not usual eyes, they work like little hands too and grab things. I am studying one of these eyes that sees weird stuff, like those things that grow on your food when it goes off. But this eye doesn't do it alone. And that makes it exciting. It has some other friends helping; the more eyes the better! All-in-one they catch the stranger and they eat it. Once eaten, they show the left-over little pieces to their cell-friends. So that they know what kind of bad guys to fight. They also call more friends in if there is a lot of it to eat. This is how our body keep us free from being sick and stay happy, isn't it amazing?" @Analobpas, talking about C-type lectins

"When it is cold the Big Water becomes ice. In the long night the Big Water near the place of the long night which has no big white animal becomes ice more quickly than it does in the place of the long night which does have big white animals. I felt the ice and the big water under the ice with better senses than people have, and now know why the ice that grows from the big water sometimes grows with ice leaves on its bottom." Alex Gough, PhD thesis, University of Otago

"People ask how many of a kind of thing there are; the thing might be a kind of number, or something like a number. I, together with others, work out how many of those things there are by understanding the way some kinds of spaces look; these spaces are, in a way, the same as the things about which we ask, 'how many,' but in another way they are different. This allows us to use different ideas when we think about them, and answer some questions about numbers which could not be answered before."â€¨ Jordan Ellenberg, number theorist. (Blog, professional homepage)

"Now, you have your two things that you think will help the sick people get better. Give one to the people in group one, and the other to the people in group two. If you can, it's a really good idea to make sure that the sick people don't know which group they are in, or what they are having to make them get better. The same is true for the people working on the problem. This is for a good reason: we have found that people get better faster when they think they have been given something that works well to make them feel better, even if they haven't really.

Arika Okrent is editor-at-large at TheWeek.com and a frequent contributor to Mental Floss. She is the author of In the Land of Invented Languages, a history of the attempt to build a better language. She holds a doctorate in linguistics and a first-level certification in Klingon. Follow her on Twitter.

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