字幕表 動画を再生する 英語字幕をプリント Hey BrainStuff, Jonathan here. Lots of situations can leave you stranded in the wild without supplies: Camping miscommunications, unexpected side quests, alien abductions with imprecise return drops, and so on. Whatever the reason you find yourself out there, you'll need to find water. A minimum of two quarts per day to maintain good health – that is, to keep your blood circulating. Which you want to do. And that brings us to today's question: How do you find water in the wild? But first, I should mention that this information is for your education only. Legally speaking, I can't recommend that you do anything I say. Let's assume that you can't find any large sources of fresh water: There's not a raincloud in the sky, and no streams, rivers, or lakes nearby. You can dig a well. Look for mud, or damp soil in a dry riverbed -- there may be groundwater near the surface. Dig a hole about a foot wide and a foot deep. If there's water, your well will start filling up. Even in the desert, you can try digging at the low point between dunes, near vegetation. Put rocks in the bottom of your well to keep sediment from stirring up into the water, and line the sides with wood to prevent the walls from caving in. Well water needs to be purified before you drink it. Give it a boil for 10 minutes. Even water that looks clean can harbor nasty microbes that will make you sicker than I get after I have shrimp. But if your wells turn up dry, you can create structures to collect water from thin air. Like a solar still. You'll need some plastic sheeting, a container to collect the water, and a rock. Having a length of tubing or some definitely-non-poisonous vegetation would be a bonus. Choose a damp bit of ground that gets sunlight for most of the day. Dig a bowl-shaped hole about 3 feet across and 2 feet deep. In the bottom, dig out enough space to place your container. If you have a tube, place one end at the bottom of the container and secure the other end on the surface outside the hole. If you have some leaves or other greenery that you know for sure are not toxic, tear them up and add them to the walls of the bowl. Place the plastic loosely over the hole and hold down the edges with rocks. But, not the one you've put aside. That one, you want to put in the center of the sheet so that it sags in a little more than a foot, directly over the container. Add more rocks and soil to the edges of the sheet for stability. The heat of the sun will evaporate moisture in the ground, producing condensation on the plastic. It'll drip and collect in your container, and you can either sip it directly through your tube or retrieve the container at sunset. If your energy is low, you'll want to avoid all that digging. The transpiration technique yields less water, but all it requires is tying a knot in a plastic bag. Find a definitely-non-poisonous leafy tree or shrub that will be in the sun for most of the day. Tie the bag around a branch. Over the course of the day, the plant will 'exhale' (or transpire) water vapor that'll collect at the bottom of the bag. Untie it or poke a hole in it to collect the water, then tie it off again and reuse the bag. Plants transpire a lot – about 10 percent of the moisture in our air comes from transpiration. Water you get from a solar still or transpiration should be safe to drink, but it never hurts to give it a boil. But hey, have you ever been in a survival situation? What other survival how-tos would you like us to cover? Let us know, and to learn lots more, head to our home planet: HowStuffWorks.com.