Question: can yo make stuff grow/shrink yet?

Luke Fry answered on 15 Jun 2014:

Great question!
There are a number of ways that we do this. Primarily, heating or cooling an object will cause it to expand or contract. We might do this if for instance we have a shaft that has to fit very tightly in a hole and they are so close in size that the shaft won’t fit by hand. If we either cool the shaft down using liquid nitrogen or heat the hole up they will shrink or grow respectively. We can then press the shaft into the hole, beware though, this is known as an ‘interference fit’ and the shaft won’t come out easily!
We also have a class of materials called ‘smart materials’ and within this class are some materials known as ‘Piezoelectric.’
This is a property where if an electric current/voltage is put through the material, then it will change shape. It also works in reverse. We use this phenomenon in components called piezoelectric actuators. We take very thin slices of this material and layer them on top of each other. When we apply the electricity the combined tiny change in size of each piece creates a meaningful change in size overall. We can very accurately control motion using these components.
As for a ‘honey I shrunk the kids’ type invention we may be a little way off!