What happens when you heat a plastic cup?

Shrinky dinks!

Well, it's the same science as shrinky dinks, anyway. 

Today we see Steve Mould heating up polystyrene cups (recycling code 6) and allowing them to shrink back toward their original, flat shape.

Fun times...

Smart Materials of the Future - with Anna Ploszajski

"Rock-paper-scissors is a game that you use to compare materials' properties. The rock blunts the scissors because rock is harder than stainless steel."

C'mon, nerd, rock-paper-scissors is just a game like mumbledepeg or roshambo.

The simplicity of showing a smart material via pine cones is brilliant.

Oh, I found a definition of smart materials that I very much like (via BBC): "[s]mart materials have properties that react to changes in their environment. This means that one of their properties can be changed by an external condition, such as temperature, light, pressure or electricity. This change is reversible and can be repeated many times."

Other smart materials mentioned in the video are lime mortar from the Egyptian pyramids, piezoelectric quartz crystals, thermochromic pigments (on a mug), NiTiNOL, and ferrofluids. Most of the latter materials are applied to the future of airplane design.

Mitch Anthamatten Explains a Shape-Memory Cycle Involving Strain Induced Crystallization

Wait, a shape memory polymer?

There's a bunch of good connections here to what we teach in our material science course.

• The polymer switches from being largely amorphous to largely crystalline on addition of strain.
• The addition of heat energy then causes the polymer to shift back to amorphism.
• The phase change happens around body temperature, like the stints we talk about.
• We have a solid-state phase change.
• At 0:55, the professor says the energy is 'enough to melt those crystals.' I'm way less knowledgeable and more a neophyte about all this than he is, but that sounds wrong to me. I don't think of a crystalline solid changing to an amorphous solid as 'melting.'

All that in less than two minutes time...

That's better than watching the Kentucky Derby.