YouTube: https://youtube.com/watch?v=Fnd-2jetT1w
Previous: Planetary Plants: Crash Course Kids #45.2
Next: Normal Stuff in Not-So-Normal Places: Crash Course Kids 46.2

Categories

Statistics

View count:170,808
Likes:1,437
Dislikes:74
Comments:148
Duration:04:20
Uploaded:2016-02-24
Last sync:2018-11-19 06:30
Ever heard of Oobleck? How about Non-Newtonian fluids? Well, today Sabrina is going to show us that things can sometimes behave like a solid, and sometimes like a liquid depending on how much force is applied to them. In this episode of Crash Course Kids, we'll talk about some weird stuff that's still... normal.

Watch More Crash Course Kids: https://www.youtube.com/user/crashcoursekids

///Standards Used in This Video///
5-PS1-3. Make observations and measurements to identify materials based on their properties. [Clarification Statement: Examples of materials to be identified could include baking soda and other powders, metals, minerals, and liquids. Examples of properties could include color, hardness, reflectivity, electrical conductivity, thermal conductivity, response to magnetic forces, and solubility; density is not intended as an identifiable property.] [Assessment Boundary: Assessment does not include density or distinguishing mass and weight.]

Want to find Crash Course elsewhere on the internet?
Crash Course Main Channel: https://www.youtube.com/crashcourse
Facebook - https://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/thecrashcourse
Tumblr - http://thecrashcourse.tumblr.com

Credits...
Producer & Editor: Nicholas Jenkins
Cinematographer & Director: Michael Aranda
Host: Sabrina Cruz
Script Supervisor: Mickie Halpern
Writer: Kay Boatner
Executive Producers: John & Hank Green
Consultant: Shelby Alinsky
Script Editor: Blake de Pastino

Thought Cafe Team:
Stephanie Bailis
Cody Brown
Suzanna Brusikiewicz
Jonathan Corbiere
Nick Counter
Kelsey Heinrichs
Jack Kenedy
Corey MacDonald
Tyler Sammy
Nikkie Stinchcombe
James Tuer
Adam Winnik

 Introduction


You know what we haven't talked about in a while? Things that matter. Like mass and materials and particles. I guess what I mean is things that have to do with matter.
We've already talked a lot about the different states of matter. You know, some matter comes in the form of a solid, others in a liquid, and still others in a gas. But are you ready for a question that will bend your brain a little? What if there's matter that fits into more than one of these categories? (0:33) Is there such a thing? If there is, what's it like? And can I make some? Maybe... in my kitchen.

 States of Matter


Before I answer any of these questions, let's take a closer look at different states of matter. (0:49) You remember what a solid is. It's matter that has a definite size and shape, like this desk that I'm sitting at or the clothes that I'm wearing and well all of me. I'm a person with a definite size and shape. 
(1:00) Liquid is matter that has a definite size, but no definite shape. The water in this glass is a liquid. It has a definite size, but no definite shape. Like you could say that my desk is "desk-shaped", but there's no such thing as "water-shaped".
(1:13) And a gas is matter that has no definite size or shape. The air around me and you is a gas. It's not shaped like anything and its size changes depending on how big the container is that it's in. 
(1:24) Now all solids, liquids, and gases are materials or objects made of matter. And all materials have properties, or traits that help identify them like their color or shape or size or temperature or weight.

 Non-Newtonian Fluids


(1:36)And now that you're properly refreshed on the states of matter, I'm going to cheat and answer our big question a little early. Or at least part of it.
Yes, some materials aren't so easily lumped into just one state of matter. (1:47) These unusual materials can actually act like multiple states of matter.   Neat, right?
(1:52) Wanna meet just such a material? Then let me introduce you to Non-Newtonian Fluids. The non-what-now?
(1:58) Non-Newtonian fluids are substances that don't behave like we'd expect them to. These fluids might look like one thing, but they behave like another. 
So, what makes a substance Non-Newtonian? (2:09) Let's find out by making a Non-Newtonian mixture of our own. Say hello to Oobleck. 

 Investigation


(2:18) Believe it or not, I didn't make this word up. It comes from a book written by Dr. Seuss. You know the guy who wrote The Cat in the Hat? In another book he wrote called Bartholomew and the Oobleck there's a king who gets bored with normal, everyday weather so  instead he makes sticky stuff fall from the sky. 
(2:33) That's where oobleck, the stuff that we're going to play with today, gets its name. But the stuff we're talking about is real. Our oobleck is a Non-Newtonian substance with a pretty simple recipe. No magical kings required.
(2:45) All you need is about one and a half cups of cornstarch, about one cup of water a big bowl, and a spoon. Pour the cornstarch into your bowl and slowly add some water. Keep stirring until the mixture feels kind of like honey. In the end, it should look like this. 
(2:58) Now  grab some of this goo in your hand. When you squeeze it, it will form a solid ball in your palm. But, when you unclench your fists and release the pressure it will slide between your fingers, like a liquid. 
(3:10) All fluids have a property known as viscosity, which is basically the rate at which a fluid flows. And Newtonian fluids or "normal fluids" flow at a consistent rate. But Non-Newtownian fluids or "non-normal" fluids flow at a different rate depending on how much force or pressure is applied to them. 
(3:27) So your oobleck flows at a much slower rate when pressure is applied to it, acting like a solid. But, when the pressure is removed, it flows faster and behaves like a liquid. 
(3:36) Good for you oobleck! Being normal is overrated, right?

 Conclusion


(3:44) So if an object's viscosity, or flow rate, is not constant, or changes depending on the pressure applied to it, it's a Non-Newtonian fluid. Which means, yes, some materials can fit into more than just one state of matter. 
(3:57) These materials are called Non-Newtonian fluids. And they don't play by your regular rules of matter. They'll be a solid sometimes and then a liquid at others. You do you, Non-Newtonian fluids. I like your style.