Water purifiers are already portable, but not as portable as this crazy invention. Created by Marcus Triest and Ryan Lynch, the Solar Bag can be worn like a shoulder bag and holds up to 2.5 gallons of water. In a feat of ingenuity, the bag is designed to use sunlight to purify the stored water, allowing you to filter drinking water on the go.
The bag is made from two layers of polyethylene—a clear, high-clarity layer on the outside and a black layer on the inside. The top layer allows the maximum amount of UV rays to enter, while the black layer traps the heat which then disinfects the water.
The purification process takes around six hours; afterwards, the water can be poured through a built-in spigot on the bottom. Best of all, the designers stated that the bag uses less than $5 worth of materials.
While the bag is being designed for use in developing nations, I imagine it would be just as useful for long-distance hikes, camping, and military applications. I also imagine it'd be pretty easy to make at home. It's basically just two layers or plastic, right? As long as you can get your hands on some high-clarity polyethylene and black polyethylene.
If you don't feel like hunting down plastic, you can always try the more used SODIS method with just a PET bottle. And if you don't feel like hunting down water, maybe you'd like to purify your urine instead?