Elements of Literature foreshadowing and Flashback Flashcard

Elements of Literature foreshadowing and Flashback Elements of Literature foreshadowing and Flashback Flashcard Elements of Literature foreshadowing and Flashback

Mohs Scale of Hardness - Identify Rocks Minerals

Mohs Scale of Hardness - Identify Rocks Minerals There are many systems used to measure hardness, which is defined several different ways. Gemstones and other minerals are ranked according to their Mohs hardness. Mohs hardness refers to a materials ability to resist abrasion or scratching. Note that a hard gem or mineral is not automatically tough or durable. About the Mohs Scale of Mineral Hardness The Mohs (Mohs) scale of hardness is the most common method used to rank gemstones and minerals according to hardness. Devised by German mineralogist Friedrich Moh in 1812, this scale grades minerals on a scale from 1 (very soft) to 10 (very hard). Because the Mohs scale is a relative scale, the difference between the hardness of a diamond and that of a ruby is much greater than the difference in hardness between calcite and gypsum. As an example, diamond (10) is about 4-5 times harder than corundum (9), which is about 2 times harder than topaz (8). Individual samples of a mineral may have slightly different Mohs ratings, but they will be near the same value. Half-numbers are used for in-between hardness ratings. How to Use the Mohs Scale A mineral with a given hardness rating will scratch other minerals of the same hardness and all samples with lower hardness ratings. As an example, if you can scratch a sample with a fingernail, you know its hardness is less than 2.5. If you can scratch a sample with a steel file, but not with a fingernail, you know its hardness is between 2.5 and 7.5.   Gems are examples of minerals. Gold, silver, and platinum are all relatively soft, with Mohs ratings between 2.5-4. Since gems can scratch each other and their settings, each piece of gemstone jewelry should be wrapped separately in silk or paper. Also, be wary of commercial cleaners, as they may contain abrasives that could damage jewelry. There are a few common household items on the basic Mohs scale to give you an idea of how hard gems and minerals really are and for use in testing hardness yourself. Mohs Scale of Hardness Hardness Example 10 diamond 9 corundum (ruby, sapphire) 8 beryl (emerald, aquamarine) 7.5 garnet 6.5-7.5 steel file 7.0 quartz (amethyst, citrine, agate) 6 feldspar (spectrolite) 5.5-6.5 most glass 5 apatite 4 fluorite 3 calcite, a penny 2.5 fingernail 2 gypsum 1 talc

Trends in Giving Research Paper Example | Topics and Well Written Essays - 250 words

Trends in Giving - Research Paper Example A second trend seen over the past decade is the increasing levels of contributions gathered by NGO’s (Non-Governmental Organizations). Funds have been pouring into these organizations because they have been billed as being able to address global issues such as famine or AIDS better than individual governments. A trend within this segment of giving is the increase of funds flowing from mega private funds such as the Soros Fund, the Bill and Melinda Gates Foundation and Ted Turner. Greater transparency in NGO’s have attracted these mega private donors because they can be more assured that their funds are going to the delineated cause. The problem of needing to steer the NGO towards the agenda of the mega private donor is a real risk, but one many NGO’s must take due to declining volunteerism and donations from other private sources (Greensmith, 2001) Another interesting gauge of trends in giving that is extremely current is the development of the PGI (Philanthropic Giving Index) at the University of Indiana. The PGI works on a similar concept as the Consumer Confidence Index. It attempts to measure the likelihood that potential donors will give to charity in the coming year. It gauges the public’s reaction to various fundraising techniques currently employed and surveys them as to how likely they would be to give if approached using these techniques. Currently, the PGI is at an all time low of 64.8. This is down 27% from the PGI that was recorded in December of 2007 (Raiton,