It’s been an odd week here at HowStuffWorks.com. We’re preparing for the Thanksgiving holiday next week. So far, the TechStuff crew has painstakingly determined how turkeys work, whether cranberry sauce makes a good cooling system for your PC and how much pie Chris can eat before he says he’s not feeling well (it’s more than you’d think!). We’re also creeping toward that magical time of year when Chris and I have to revisit the predictions we made for 2010 and consider what technological advancements we’ll see next year. But before we open that can of worms, we have a few other episodes to talk about.

Do you use rechargeable batteries? Have you ever wondered what makes them special? Or pondered at what might happen if you put normal batteries into a recharging dock (note: never, ever do that — it’s bad news). On Monday’s TechStuff, Chris and I talk about what makes rechargeable batteries work. On the surface, it’s a pretty simple concept — just reverse the flow of electrons in a battery and you’ll reverse the chemical reactions inside it.

But to do that safely is a bit more complicated. Without the proper precautions, you could overcharge a battery and cause it to short circuit. Some batteries contain flammable materials and can burst into flame or explode! Fortunately, most rechargeable battery systems have safety measures in place that prevent catastrophe.

Wednesday’s episode was about rare earth metals. As Chris says in the show, these metals are neither rare nor earth. But they can be difficult to mine. That’s because most of these metals occur naturally as oxides, combined with other materials. You’re not going to find many neodymium mines scattered around the world.

Electronics manufacturers use rare earth metals in a number of applications. Some become magnets used in speakers like an mp3 player’s earbuds. Others are necessary components for displays. And almost all the world’s supply of rare earth metals come from one place: China. China has driven down the cost of rare earth metal mining so low that it makes more sense to buy materials from China than it does to invest in mining operations.

That’s turned out to be a problem. In Martin LaMonica’s article about rare earth metals, he points out how dependence upon China for these metals can lead to shortages. In some cases, China may need more of the metals than it produces and so it may cut off exports. In other cases, China may deny a country the chance to purchase rare earth metals as a political maneuver. Ultimately, what this means is that the world needs to invest in other rare earth metal mines if we’re to continue producing electronics without worrying about our supply of rare earth metals disappearing.

That wraps it up for this week on TechStuff. Remember to follow us on Twitter and Facebook!