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Describes the building blocks of matter.

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Shape Shifters

Shape Shifters

Credit: Jason Regan
Source: http://commons.wikimedia.org/wiki/File:Braces_smile_purple.jpg
License: CC BY-NC 3.0

Got braces? If so, you may have a cool type of alloy in your mouth!

Amazing but True!

  • Alloys are mixtures of metals that have properties that the individual metals don’t have. One property of some alloys is the amazing ability to change shape.
  • These alloys are called shape-memory alloys. The alloy named nitinol is an example. It’s a mixture of the transition metals nickel and titanium. Nitinol is used in braces to apply pressure to teeth and gently move them into new positions.
  • Credit: Lenore Edman
    Source: http://www.flickr.com/photos/lenore-m/9462152790/
    License: CC BY-NC 3.0

    Nitinol is also used to make stents that can keep arteries open [Figure2]

  • Watch this video to learn the science behind nitinol and other shape-memory alloys: http://ed.ted.com/lessons/ainissa-ramirez-magical-metals-how-shape-memory-alloys-work

What Do You Think?

At the links below, learn more about shape-memory alloys and their uses. Then answer the following questions.

  1. The science behind shape-memory alloys starts with atoms. How do atoms naturally arrange themselves?
  2. How do atoms of shape-memory alloys change when heated?
  3. What are some practical applications of shape-memory alloys?
  4. If you bend or twist a nitinol wire, how can you get it to return to its original shape?
  5. What are two limitations on shape-memory alloys?

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Image Attributions

  1. [1]^ Credit: Jason Regan; Source: http://commons.wikimedia.org/wiki/File:Braces_smile_purple.jpg; License: CC BY-NC 3.0
  2. [2]^ Credit: Lenore Edman; Source: http://www.flickr.com/photos/lenore-m/9462152790/; License: CC BY-NC 3.0

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