On the left hand side of the sheep simulation above, you can watch the sheep shuffling between the farms at random. There doesn’t seem to be any pattern to their motion. The Chimney Balloon is made from plastic, and is designed to be inflated, using a pump or by blowing into a pipe, to fill the chimney and prevent cold air from coming in and warm air from travelling up and out.

The Chimney Balloon was started up by an engineer in the 1980s, although many other companies have since set up offering similar products. In 2017, The Chimney Balloon Co. was bought by Chimney Sheep Ltd and although the products they offer are different they now work together. At this point, you might be wondering what this has to do with entropy. Well, entropy is just a fancy word for ‘number of possible arrangements’. Entropy is a count of how many ways you can rearrange the ‘insides’ of a thing (its microscopic internals), while keeping its ‘outwardly’ (macroscopic) state unchanged. (Technically it’s the log of the number of these arrangements, but that’s just a mathematical convenience and doesn’t affect our discussion.) It’s important to keep in mind that there’s no special guiding force driving these sheep to spread out and increase entropy. It’s just that there are fewer ways to keep the sheep concentrated, and more ways to spread them out. There are fewer arrangements where the sheep (energy) are concentrated, and more arrangements where the sheep (energy) are spread out. Going down this road leads us to some of the biggest unanswered questions about the cosmos: how did our universe begin, how will it end, and why is our past different from our future? Counting Sheep About a month later, on Nov. 21, Pilâtre de Rozier and theMarquis d'Arlandes, a French military officer, made the first free ascent in a hot air balloon. The pair flew from the center of Paris to the suburbs, about 5.5 miles (9 km), in 25 minutes. Benjamin Franklinwrote in his journal about witnessing the balloon take off:

Where Are We Going?

And yet, for some reason, when we get to large collections of atoms, a one-way street emerges for the direction in which events take place, even though this wasn’t present at the microscopic level. An arrow of time emerges. We observed it lift off in the most majestic manner. When it reached around 250 feet [76 m] in altitude, the intrepid voyagers lowered their hats to salute the spectators. We could not help feeling a certain mixture of awe and admiration."

So why are we picturing this pastoral scene? Because we can use it to understand the physics of solids. When you heat a solid, you're adding energy to it. We usually think of energy as something continuous, something that flows. But when you get down to the atomic level, quantum mechanics teaches us that energy comes in discrete chunks. On Jan. 19, 1784, in Lyons, France, a huge balloon built by the Montgolfiers carried seven passengers as high as 3,000 feet (914 m), according to the U.S. Centennial of Flight Commission.

The Solution to Our Mystery

So although the sheep are shuffled at random, over time, a pattern emerges. Some states are more likely than others. Why Sheep Spread Out