When you imagine the desert, you probably think of a very hot place covered with sand.Although this is a good description for many deserts. Earth's I with ice:Antarctica. In order for an area to be considered a desert, it must receive very little rainfall. More specifically, it must receive an average of less than ten inches of precipitation - which can be rain, sleet, hail , or snow - on the ground every year. Antarctica, the coldest place on earth, has an average temperature that usually falls below the freezing point. And because cold air holds less moisture than warm air, the air in Antarctica does not hold much moisture at all. This is evident in the low precipitation statistics recorded for Antarctica. For example , the central part of Antarctica receives an average of less than 2 inches of snow every year. The coastline of Antarctica receive a little bit more-between seven and eight inches a year. Because Antarctica gets so little precipitation every year, it is considered a desert. When precipitation falls in hot deserts, it quickly evaporates back into the atmosphere. the air over Antarctica is too cold to hold water vapor, so there is very little evaporation. Due to this low rate of evaporation, most of the snow that falls to the ground remains there permanently, eventually building up into thick ice sheets. Any snow that does not freeze into ice sheets becomes caught up in the strong winds that constantly blow over Antarctica. These snow-filled winds can make it look as if it is snowing. Even though snowfall is very rare there, blizzards are actually very common on Antarctica.
Africa's Sahara Desert is the second largest desert on is the earth. Based on the information in the passage what characteristic must the Sahara share with Antarctica?
Gold used in jewelry is mixed with harder metals to add strength and durability. The metals added can also be used to change gold's color, giving it a for the natural yellow tone of pure gold. Mixtures like these, of less costly metals with more valuable ones, are called alloys. Copper and silver are the most common metals mixed with gold to make yellow gold jewelry. White gold is usually made with an alloy of gold and nickel.The measure of is called gold's purity is called a karat. The higher the karat rating, the higher the amount of pure gold. 24 karat is pure gold,18 karat is 75% pure gold, 14 karat is 58.5% pure gold,and 9 karat is 37.5% pure gold. All other things being equal, the higher the percentage of pure gold used in the alloy, the more valuable and expensive the jewelry will be.Gold jewelry pieces are usually stamped with a marking to identify the karat amount. White gold that is 24K is too soft for jewelry, 18K,14K and 9K gold are all appropriate for jewelry, and they all make pieces that look great and wear beautifully.
Based on information in the passage,it can be understood that pure gold is