Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren Bogle bomb here. You can't easily put the toothpaste back into the tube. You can't expect molecules of steam to spontaneously migrate back together to form a panful of water. If you release a bunch of corky puppies into a field, it's very unlikely that you're going to be able to get all of them back together into a crate without doing a ton of adorable fluffy work.
These are the problems associated with the second law of thermodynamics, also known as the law of entropy. Thermodynamics is important to various scientific disciplines, from engineering to natural sciences, to chemistry, to physics, and even economics. A thermodynamic system is a confined space which doesn't let energy in or out of it. The first law of thermodynamics has to do with the conservation of energy. You know that the energy in a
closed system remains constant. That is, energy can be neither created nor destroyed, that is, unless the system is tampered with from the outside. However, the energy in a system constantly changes. Forms of fire can turn chemical energy from a plant into thermal and electromagnetic energy. Battery turns chemical energy into electrical energy. The world turns and energy becomes less organized. This is entropy, and it's one of the laws that demonstrates how our universe works. So entropy is
a measure of the disorder in a closed system. According to the second law of thermodynamics, entropy in a system almost always increases over time. You can do work to create order in a system, but even the work that's put into reordering increases disorder as a byproduct, usually in the form of heat. Because the measure of entropy is based on probabilities, it is of course possible for the entropy to decrease in the system on occasion, but it's
statistically very unlikely. It's harder than you think to find a system that doesn't let any energy in or out. Our universe is as good of an example as we have, but after accounting for the fact that it's usually not going to be mathematically perfect, entropy does help describe how disorder happens in a system as large as the galaxy
or small as a thermos full of coffee. However, entropy doesn't have to do with the type of disorder you think of when you lock a bunch of chimpanzees in a kitchen, it has more to do with how many possible permutations of mess can be made in that kitchen, rather than how big of a mess is possible. Of course, the entropy depends on a lot of factors, how many chimpanzees there are, how much stuff is being stored in
the kitchen, and how big the kitchen is. So if you were to look at two kitchens, one very large and stocked to the gills but meticulously clean and organized, and another that's smaller, with less stuff in it but pretty baseline messy, it's tempting to say that the messier room has more entropy, but that's not necessarily the case. Entropy concerns itself more with how many different states are
possible than how disordered it is at the moment. A system therefore, has more entropy if there are more molecules and atoms in it, and if it's larger, and if there are more chimpanzees. Entropy might be the truest scientific concept that the fewest people actually understand. Honestly, me sort of included. The concept of entropy can be very confusing,
partly because there are actually different types. The Hungarian mathematician John von Neumann lamented the situation by saying, whoever uses the term entropy in a discussion always wins, since no one knows what entropy really is, so in a debate, one always has the advantage. We spoke via email with one Marko Popovich, a post auctoral researcher in bio thermodynamics in the School of Life Sciences at the Technical University of Munich. He said, it's a little hard to define entropy.
Perhaps it's best defined as a non negative thermodynamic property which represents a part of energy of a system that cannot be converted into useful work. Thus, any addition of energy to a system implies that a part of the energy will be transformed into entropy, increasing the disorder in the system. Thus, entropy is a measure of disorder of a system. But don't feel bad if you're still confused. The definition can vary depending on which discipline is wielding
it at the moment. For example, in the mid nineteenth century, a German physicist named Rudolph Classius, one of the founders of the concept of thermodynamics, was working on a problem concerning efficiency in steam engines, and he invented the concept of entropy to help measure useless energy that cannot be
converted into eve full work. A couple decades later, Ludwig Boltzman entropies other founder used the concept to explain the behavior of immense numbers of atoms, like even though it's impossible to describe the behavior of every single particle in a glass of water, it's still possible to predict their collective behavior when they're heated using a formula for entropy,
Popovich said. In the nineteen sixties, the American physicist T. S. Jayne's interpreted entropy is information that we miss to specify the motion of all particles in a system. For example, one mole of gas consists of six times ten to
the power of twenty three particles. Thus, for us, it is impossible to describe the motion of each particle, so instead we do the next best thing by defining the gas not through the motion of each particle, but through the properties of all the particles combined temperature, pressure, total energy.
The information that we lose when we do this is referred to as entropy, and the terrifying and or fascinating concept of the heat death of the universe wouldn't be possible without entropy, because our universe most likely started out as a singularity, as an infinitely small ordered point of energy that ballooned out and continues expanding all the time. Entropy is constantly growing in our universe because there's more space and therefore more potential states of disorder for the
atoms here to adopt. The scientists have hypothesized that long after you and I are gone, the universe will eventually reach some point of maximum disorder, at which point everything will be the same temperature, with no pockets of order like stars and chimpanzees to be found. And if that happens, we'll have entropy to thank for it. Today's episode was written by Josceline Shields and produced by Tyler Klang. For more on this lots of other top x visit how
stuff works dot com. Brain Stuff is a production of I Heart Radio. For more podcasts from my heart Radio, visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.