Making inferences in informational texts

0:00- [Narrator] Readers, hello. Greetings from my secret lab, deep beneath Khan Academy, where I combine what I read with what I already know to make a mysterious chemical substance, known as an inference. (speaker laughs) Sorry, what is an inference? Great question, readers.

0:19Thank you for asking it. An inference is something you figure out by combining your background knowledge with evidence from a text or some other source. An inference allows you to fill in the gaps, to put in the missing puzzle pieces between what you read and what you know.

0:35If you're reading something and it's muddy or confusing, making an inference can help you figure it out or help you answer questions about what you're reading. Let's work this out real quick. Let's say I hate lemons, but love cookies. And this is information you already know about me.

0:51That's your background knowledge. And someone says to me, "David, would you like one of my Girl Scout cookies?" And I say, "Gross, no." Background knowledge, David hates lemons, but loves cookies. New evidence, "Would you like some cookies?" And I, a known lover of cookies say, "No."

1:08What kind of inference can you make about the cookies? Connect the dots, what's a missing puzzle piece? I shall pause, shout your answers in 5, 4, 3, 2, 1. Wow, not so loud. Okay, I got delicate ear drums. Yeah, so one inference you could make is that those are lemon cookies that I'm being offered, right?

1:33Me, David, certified lemon hater. I don't want those cookies. Inferences aren't always right, but it's more likely that I don't want the gross cookies because they've got lemon in them than for some other unknown reason, especially if I like cookies in general.

1:47Let's try another inference, this time based on a text. Many animals mark their territory in order to say to other animals, "This is my zone. Don't mess with it." For example, deer rub their antlers on trees, leaving behind their scent, but Australian wombats don't have antlers and other scent-marking activities don't work well in their steep, rocky habitats.

2:11Instead, they use their droppings to mark where they live. But here's what makes wombats unique. Their poop is cube shaped. So that's gross and fascinating, and it allows me to draw a cube instead of getting Khan Academy banned from your school's intranet, win-win.

2:29I make inferences as I read when I have unanswered questions. And my unanswered question when it comes to this paragraph is, why does having cube-shaped poop help a wombat mark its territory? Take some time and do your own background info plus evidence equals inference table.

2:47I'll put on some music, pause the video if you need to, and meet me back here in 10. Please, Mr. Music, will you play? (light music) All right, so here's what I know going into this text, my background information. Square things don't roll. And here's the evidence that I learned from reading the text.

3:13Wombats live in steep rocky habitats. They use their droppings to mark their territory and their poop is cube-shaped. So given what I know and given what I've just read, I can infer that cube-shaped poop helps a wombat mark its territory because it stays put in a steep, rocky habitat.

3:33Droppings that roll downhill would be useless for marking territory because they'd just roll away. But a cube, a cube stays where you put it. So I'm gonna simplify that to cube poop stays put. So that's how a cube shaped poop helps a wombat mark its territory, and that's the skill of inference, folks.

3:51I'll be here all week, you can learn anything. David out.