Hi. I am Tracy V. Wilson and I'm Holly Fry. We are the co hosts of the Stuff You Missed in History Class podcast from how Stuff Works dot com. And as you might suspect from the name, what we like to talk about are the things that are of historical significance but maybe you didn't hear about in your standard history class. So sometimes they are famous figures and we're talking about the lesser known parts of their lives. Sometimes they are people in groups and places that are
often overlooked in history class. Lots of cool stuff, So come and join us. Welcome to brain Stuff from how Stuff Works. Hey, brain stuff, this is Christian Seger fracking. You've heard of it, you know it's controversial, but you might not know what it actually involves. Never fear. Here at brain Stuff, we're going to put some fracking knowledge
in your brain. Fracking is the delightfully cheeky sounding nickname for hydraulic fracturing, which sounds a little bit less delightful and less cheeky and more like something you would do to your enemies. And I don't know StarCraft, but no, it is something we do to rocks in the simplest terms. Hydraulic fracturing is a way of getting more of the valuable fluids like oil and natural gas out of geologic
formations under the ground. Deep under Earth's surface, there are deposits of rock that have huge reserves of oil and natural gas within them. But these fossil fuels aren't like big lakes where you can just stick a straw in and suck it. Is not a milkshake. No, these reserves of oil and natural gas are found locked up in pores distributed throughout vast layers of rock like shale. So how do you get them out at a reasonable pace? Okay, different processes are used, but let's look at the typical
fracking set up for something like shale gas. You start with a deep vertical well, drilling a hole down to the level of the shale that you want to mind. The depth will vary, but just for example, one company claims it's average fracking well depth is seven thousand, seven hundred feet. That's deep almost one and a half miles or about two point three kilometers. When you're at the right depth, you take a nine degree turn and you continue to drill horizontally parallel to the target rock layer.
This horizontal section of the well can also travel thousands of feet. Now here's where the fracturing comes in. First, you open up holes in the horizontal section of the pipe. Then you vigorously push a liquid cocktail known as fracking fluid down into the borehole under high pressure. This fracking fluid is usually a mixture of water, some chemical additives like acids to help dissolve the rock, and gels to
thicken the fluid, and finally solid particles called profits. And we're going to get to those profitts in a second. When the mixture reaches the horizontal section of the pipe, it bleeds out through those holes into the surrounding rock, and the extremely high pressure causes the rock to form tons of little fractures or cracks. Through these cracks, the reserves of fossil fuels contained in the rock can escape into the well to be pumped back up to the surface.
What once was entombed in ancient rock is now the way to powering your car or heating the water for your next shower. And those propins I mentioned, which are often just grains of sand, they help prop the cracks in the rock open, so the Earth's precious bodily fluids continue to escape into the well without the miners applying continuous pressure, So that's how it works. But then there's the entirely separate question of whether fracking is a good idea.
It's mega controversial in many parts of the world. Some people claim it consumes too much fresh water, and they worry about what will be done with the fracking fluid after it's been used, and some opponents wonder if it will create earthquakes or cause chemical contaminants to leak into our groundwater. Check out the brain stuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com.