SCIENCE HOMEWORK FOR 8TH A / B

SCIENCE HOMEWORK 8 A/B LCDA:DIANA MONTERO

WATER IN DESERTS Deserts are fantastic places to explore and make great destinations for hikers, backpackers, mountain bikers and horseback riders who have a yearning for solitude and wild natural beauty. But deserts are what they are because of their scarcity of water, and this lack of easily available drinking water makes desert travel both difficult and dangerous. Those who would travel off the beaten path in desert regions are, of course, well-advised to carry all the drinking water they plan to need for their excursion, but the unexpected can always happen, so it pays to have some knowledge of how to locate water in the event you run out, or get lost or injured and have to outstay your available supply. Most people simply assume there is no water to be found at all in the desert, but in truth, there are only a few extreme deserts in the world that are totally devoid of water. These are places like Death Valley and parts of the Sahara where there is absolutely no vegetation and little if any life. In most other desert and arid mountain regions, there is quite a bit of life, though species are limited and all are well-adapted to surviving in conditions of extreme drought. These deserts all receive some rainfall or snow, though it may be months between such events and there may not be any readily available surface water such as lakes or streams. In such deserts, one way to find water is to dig for it. Water often seeps just beneath the surface, where it is retained by underlying layers of rock and cannot evaporate since it is not exposed to the sun. The key to finding such hidden reservoirs of water is to know where to dig. Dry washes are often located in ravines or hollows between hills or in the bottoms of canyons in mountainous deserts. These washes are streambeds in times of rare rains and can become raging torrents in a flash flood. Water is often found by digging in such dry stream beds. You can make an educated guess as to where to dig by looking for signs of moisture, such as damp sand. If conditions are too dry for this to occur, look for areas along the streambed with the most vegetation and dig adjacent to this greenery. Chances are you’ll find moisture within a couple of feet of the surface if there is much plant life nearby. Water often collects beneath the surface in areas of the streambed where there are sharp bends. Dig near the outside of such bends if there is no indicating greenery anywhere to be found. If you do find water by digging like this, it may not be in large quantities. When you dig down and find wet sand or gravel, keep scooping out this material until water gradually seeps into the hole. If there is not enough water to dip out and drink in a conventional way, you can sponge it up with a shirt or other article of clothing and squeeze it out into your mouth. Another way to get water in the desert with this sponging method is to use cloth like this to mop up dew early in the morning. If there is any vegetation at all, there will usually be dew on it before sunrise, and you can collect surprisingly large quantities by mopping it up and squeezing out the cloth. Some desert vegetation such as certain species of cactus contains a lot of water. The barrel cactus is one example. If you can cut open some of these larger cacti to get to the pulpy inside, you can suck the water out them. Water can also be found in natural rock pockets that are common in arid mountains and hills. Sometimes these natural pools can contain a large quantity of easily obtained surface water. Before drinking such water look for signs of mineral poisoning by checking for signs of animals using the water. If you see lizard, rodent or other animal tracks leading to and from the pool, but don’t see any remains of small animals nearby, chances are the water is okay to drink. The most important thing to remember if you are stranded in a desert without water is to not give up. Don’t die of thirst when salvation may be just beneath your feet or nearby in a hidden rock grotto. If there are animals and plants living in the desert in which you are lost, then there is surely water if you know how to find it.