Quantum Physics
After spending all of this time discussing the laws of thermodynamics, we're going to throw a curveball. There's pretty good evidence that these thermodynamic laws only apply to big stuff like heat engines, power plants, and chihuahuas. Wait, how big are we talking here?
When objects get very small, like molecular sized, the laws of thermodynamics aren't as accurate3. For a long time scientists didn't know that, because they couldn't study the behavior of single molecules. Turns out, getting a bigger magnifying glass just doesn't cut it.
For example, for a long time scientists couldn't study exactly how the polymerase that replicates our DNA works. They could study the average behavior of the millions of polymerases in our personal test tubes (bodies), though, and that average behavior obeys the laws of thermodynamics.
Because of the relentless march of science, we can now study a single DNA polymerase or a kinesin (a little motor that acts like a tow truck, moving things around our cells). Check out this video that shows how a virus can stuff DNA into itself. The giant leaps in technology that now allow us to study single molecules allow us to build detailed models of what goes on inside of our cells.
Why do we care about all of this? As long as the hundreds of polymerases in our test tube behave like the thermodynamic laws predict, who cares if the individual polymerases are a little more fickle?
We care because the things we are able to observe are getting smaller and smaller. People want to build molecular motors that can be turned on and off by light particles, and quantum computers that would be able to process information much faster than the digital computers we work with today. We need to understand the thermodynamics of tiny things to develop these of nano-technologies. This is where quantum dynamics comes into play. And plays with our minds, too.
Professor Jonathan Oppenheim at University College London recently found that for very tiny objects, processes are nearly always irreversible. There are no efficient Carnot engines on the nano-scale. His research suggests that any heat engine or micro-powerplant that technologists want to build will be far less efficient than its bigger counterparts. Talk about a major bummer. This just goes to show we are never done learning and discovering. And sometimes getting bummed out along the way.