Margaret meets with a NASA material scientist, who helps invent polymers for extreme environments - think outer space!
Class Discussion Questions:
1) Consider the materials used in your shoes. Why are those materials appropriate?
2) Using clues from the video, what does "torsion" mean?
Read the Script:
[Margaret] Cotton shirt, polyester blazer, metal microphone, glass glasses, everything is made up of materials. And each meets a specific need. I wouldn't want to wear a metal jacket. And well, cotton glasses just wouldn't work. Turns out, when you need a very specific material, say for a spacesuit or a rocket, there are material scientists who go to work inventing what's needed. PhD Researcher, Tiffany Williams, is a Material Scientist at the NASA Glenn Research Center. She focuses specifically on polymers for extreme environments. She stopped by the studio to tell me all about her work. I started by asking her, "What exactly is a polymer?"
[Tiffany] Think of a polymer as a macromolecule. So you have small molecules, an example of that is salt, like sodium chloride, or water, H2O. But, a polymer is actually a macromolecule and so, on an atomic level, think of a pot of cooked spaghetti noodles, just a lots of entanglements. And so similar to how spaghetti noodles are prepared, if they're undercooked, they would tend to be a little stiffer, or if they're overcooked, they could be very fragile and soft. That's the same thing that we kind of do with polymers when we process them. Depending on how we process them, they can either be stiffer or more flexible, or more heat-tolerant. [Margaret] Well, let's take a look at some of the examples that you brought in.
[Tiffany] Right. So the first demonstration that I wanted to show is the difference between the mass. Both of those materials have a similar strength, but the polymer matrix composite is about 70-80% lighter.
[Margaret] Yeah. This metal here feels a lot heavier.
[Tiffany] Right. And one of the major benefits for using polymer matrix composites is the fact that they're lightweight. They have a much higher strength-to-weight ratio than a metal. So that helps with fuel consumption and also cost savings, which will help us reduce the cost of space travel.
[Margaret] Yeah. I could imagine it would be a lot easier to fly into space with this light polymer than it would with this heavy metal.
[Tiffany] Yes. It's definitely for better efficiency. [Margaret] And then, what about these two that you brought in?
[Tiffany] So another benefit to using polymer matrix composites, is the tailorability. If you look at this piece of glass fiber-reinforced composite, the fibers are lined up in this zero degree direction. So if you try to bend that, you'll see that it's very stiff.
[Margaret] Yeah. That does not bend.
[Tiffany] But if you try to twist it, it's very, very easy to twist in a torsional direction. But if you look at this material, and try to twist it in the same direction,
[Margaret] Okay.
[Tiffany] It's very stiff. But if you try to bend it
[Margaret] Yeah, that's not going.
[Tiffany] Right. But if you try to bend it, it's much more flexible. That's because the fibers in this composite is laid up in this crisscross formation. So, basically the direction where the fibers are laid is where the stiffness will be. So we can tailor the stiffness and the structure in the directions where we anticipate the highest loads.
[Margaret] Very neat. And so do you have any advice for a young person who might be interested in science, especially girls?
[Tiffany] Yes. I always say be willing to embrace challenges. Many times when we try to attempt our experiments the first time in the lab, the first few attempts may not be completely successful, but the important thing is to just learn from your mistakes, just like in life. Learning from mistakes is a part of the learning curve and that helps you to become an expert. The next thing that I recommend is enjoy solving problems and being curious and asking lots of questions, finding out why things or how things work the way they do.
[Margaret] Excellent. Well, thank you so much for answering my questions today.
[Tiffany] No problem. You're welcome.
[Margaret] Thanks.
