So it's bugged some people (me included, briefly), as to why Pegasi have to make the weather. This was magnified when Hurricane Fluttershy came out and we saw that not only do Pegasi have to make the weather, they have to manually get their own water. Ideas that water doesn't evaporate in Equestria like it does in ours.

This was further confused by the fact that steam can be seen several times in the show. Evaporation is the same as steam rising off a hot tub, right?

Well, kind of.

So, water molecules all have energy and are constantly moving around. When water boils, what is actually happening is that the heat is adding more and more energy to the molecules, causing them to move faster and faster, until eventually the have enough energy to overcome the surrounding air pressure, float out, and become a gas (this is a simplified version; there's more to it, and there are multiple ways it can happen, but this is the basics). An interesting side note: even though outer space is about 3 Kelvin (about -454 Fahrenheit or -270 Celsius), if you threw a glass of water out of a space ship, it wouldn't freeze, it would boil. In space, there are so few particles that the "air" pressure would be exerting far less pressure on the water than the photons coming from the sun.

Evaporation is very similar. You, see, even at room temperature, the molecules are moving around quite a lot. They inevitably bump in to each other and transfer energy. Sometimes, a molecule will end up with enough energy to escape the tyranny of air pressure. It gets into the air, floats around, and ends up in a cloud.

The simplest way to explain both the lack of natural evaporation and weather is that Equestria (or at least the majority of it) has a higher natural air pressure than our world. The pressure is too high for water to evaporate, or at least, to evaporate enough. Local pressures may vary. For example, we know that the Everfree Forest has natural weather (or at least, more natural). Things such as humidity, temperature, and even wind currents can all influence local air pressure. It's not out of the question that the area where the Forest grew has lower air pressure. After all, high humidity lowers air pressure (water molecules are lighter than air molecules, interestingly enough), and the plants seen in the Forest thrive in high humidity.

Now, pressure is reduced at higher elevation, so water existing and floating around in a gaseous form (i.e. clouds) wouldn't be a problem. I'm not going to touch how Cloudsdale works, or how Pegasi can walk on clouds, though

I'm thinking of making a new blog for stuff like this, if people enjoyed this. Any criticisms or ideas for future topics?