Determination of Variables Affecting Surface Tension Using Simple Bubble Method Essay Example

Determination of Variables Affecting Surface Tension Using Simple Bubble Method Essay Example Determination of Variables Affecting Surface Tension Using Simple Bubble Method Essay Determination of Variables Affecting Surface Tension Using Simple Bubble Method Essay 2002. Surface Tension [online]. Available at: http://mysite. du. edu/~jcalvert/phys/surftens. htm [accessed 05 July 2008]. Cheak Ching Hui, et al. , 2004. Bubbles and Surface Tension [online]. Available at: http://www1. moe. edu. sg/[emailprotected]/quest/winners/secondary/raffles_girls_sch_nc/Folders/SurfaceTension1. htm [accessed 17 June 2008] Haber, Howard. Surface Tension [online]. Available at: http://scipp. ucsc. edu/~haber/ph5B/bubble. pdf [accessed 17 June 2008] KRUSS. Theory Behind the Bubble Pressure Method [online]. Available at: kruss. info/index. php? content=http%3A//www. kruss. nfo/techniques/bubble_pressure_e. html [accessed 15 July 2008] Laidler, K. J. Meiser, J. H. , 1999. Physical Chemistry. 3rd ed. Boston: Houghton Mifflin Company. Probstein, R. F. , 1994. Physicochemical Hydrodynamics: an Introduction. 2nd ed. John Wiley Sons, Inc. Roman, F. L. Velasco, S. , Surface Tension [online]. Available at: http://www2. physics. umd. edu/~mfuhrer/course/spr02/AJP/AJP00917. pdf [accessed 09 July 2008] APPENDICES Measurement of Tube Radius Tube No. Dinside (mm)Doutside (mm)average (mm)average(m) 13. 343. 543. 440. 00344 23. 94. 44. 50. 00415 34. 7254. 860. 00486 45. 445. 95. 670. 00567 56. 386. 96. 640. 00664 Maximum Pressure Difference Conc100%75%50%25%5% cm H2O? P (Pa)cm H2O? P (Pa)cm H2O? P (Pa)cm H2O? P (Pa)cm H2O? P (Pa) Tube 11. 1107. 911. 1107. 911. 15112. 8151. 15112. 8151. 2117. 72 Tube 20. 8583. 3850. 988. 290. 988. 290. 9593. 195198. 1 Tube 30. 878. 480. 878. 480. 8583. 3850. 988. 290. 9593. 195 Tube 40. 6563. 7650. 6563. 7650. 768. 670. 768. 670. 878. 48 Tube 50. 658. 860. 658. 860. 6563. 7650. 6563. 7650. 768. 67 Calculated surface tension (N/m) Concentration100%75%50%25%5% Tube 10. 046400. 046400. 048510. 048510. 05062 Tube 20. 043260. 045800. 045800. 048340. 05089 Tube 30. 047680. 047680. 050660. 053640. 05662 Tube 40. 045190. 045190. 048670. 048670. 05562 Tube 50. 048850. 048850. 052920. 052920. 05700 Sample Calculations: where din = inside diameter of tube dout = outside diameter of tube where ? P = difference between pressure inside the bubble and outside pressure, in Pa h = manometer reading, in meters ? = density of H2O = 1000 kg/m3 g = acceleration due to gravity constant = 9. 81 m/s2 where ? = surface tension, in N/m

How to Purchase and Prepare Trees for Planting

How to Purchase and Prepare Trees for Planting Nurseries provide nearly 1.5 billion trees for planting in the United States each year. This represents over six trees annually propagated for every U.S. citizen. The United States Forest Service reports that nearly 3 million acres are forested with those billion and a half baby seedlings. For those that are interested, here are answers to questions on Tree Planting Statistics for the United States. I now want to break down planting trees in manageable bits for you. I will provide answers to the following questions with links for further information: Â   Why and Where Should You Plant Trees?When Do You Plant a Tree?How Do You Plant a Tree?Where Do You Get Trees to Plant? Why Plant a Tree? Planting a tree can have tremendous influences on communities. Tree planting improves our environment. Planting a tree can add to our incomes and decrease energy costs. To plant a tree can enhance our quality of life and improve our health. I cant think of many things that touch us so completely as does planting a tree. My point is, we need trees to be planted! Art Plotnik, in his book The Urban Tree Book, indicates eight reasons to plant trees . Trees reduce sound, produce oxygen, store carbon, clean the air, gives shade and cools, reduces wind and erosion and increases property values. This book, a big seller, attests to the fact that people also enjoy studying and identifying trees. Identifying trees is a hobby that millions of Americans practice. There are plenty to ID with over 700 tree species growing in North America alone. My most popular destination sites at About Forestry deal with identifying and naming trees. People cant seem to learn enough. First, take this simple quiz and find out how much you really know about tree planting! Where Should You Plant a Tree? Use common sense when planting a tree. If the planted tree is expected to grow tall or expand widely, give it the room it needs for future growth. Understanding species moisture, light and soil needs is extremely important. Plant according to the nursery instructions. A USDA tree and plant hardiness zone map is one good guide in helping you determine a tree’s ability to withstand an average minimum temperature. I refer to plant hardiness zones a lot when reviewing individual trees: See: USDA Tree Hardiness Zone Maps by Region More on Where You Should Plant a Tree Wildland tree planting (the most practical method of tree planting for reforestation) is done during dormant winter months, most often after December 15th but before March 31st. You may need to do it a little earlier or a little later in warmer or colder climates. Your nursery can help you decide. Always observe the ten commandments after seedlings are delivered. Although you do not plant most wildland trees during the summer you should make sure you have ordered your trees for the season by early summer. Many people who wait until fall to find available trees just might not find any seedlings. Always order your seedlings as early as you can. Planting urban trees is a little different. Horticultural planting has evolved into an all year operation because of the extra protection of a root ball with each tree. Any season is OK for planting balled or burlaped trees. More on When You Should Plant a Tree For simplicity, I want to divide planting into two categories - horticultural and wildland planting . Horticultural tree planting is geared toward urban situations where landscaping is of primary concern. Generally speaking, because these trees contain an intact root ball, they can be planted in any season. Where these higher valued saplings and trees are planted to enhance property, more effort should be spent on each individual tree. Kim Powell, Extension Horticultural Specialist, explores the types of trees available for transplanting and gives tips on purchasing, planting, and maintaining tree transplants . Here is a how to on planting balled in burlap saplings: Planting Balled Saplings Also, you would be well advised to take my Tree Wellness Quiz before planting the saplings. Dont worry about your score. The object here is to find out what you know and to give you some help with the things you dont know. Wildland planting, the preferred method for reforestation, is done over a much broader area. Even though this type of planting is cheaper on a per tree basis, it can be very expensive in total and should be done correctly. A plan can make your planting effort more effective. Reforestation using bare-root seedlings is done by government, industry, and private individuals. The plantings are most often made using coniferous species. Hardwood wildland planting is also a viable practice, but hardwood regeneration techniques also include sprouting and dormant seeds. Many times these non-planting techniques are the preferred methods of regeneration. Also, federal and state cost-share programs have historically supported funding pine, spruce, and fir planting over hardwood planting. Here is a how to on planting bare-root seedlings: Planting Bare-root Seedlings Coniferous planting techniques are similar for most species. I have included planting guides for the western United States created by Colorado State Forest Service and for the southern United Sates created by South Carolina Forestry Commission . These sources give you a good overview on how to deliver, handle, store, and transplant seedlings. You must use proper care with a big emphasis on the correct temperature range and moisture level. Again, always observe the ten commandments. More on How You Should Plant a Tree By now you have either decided to plant some trees, or have chucked the whole idea. If you are not too discouraged, let me help you get in touch with a nursery that can provide you with trees and suggest companies that can supply you with equipment necessary to the task of tree planting. First off, you can purchase trees over the Internet. I have a short list of reliable companies where you can buy a seedling or sapling online. Check out my seedling supplier source page An excellent forest nursery directory providing most tree species and covering the entire United States is maintained by the U.S. Forest Service. Also, you can find tree nurseries at most state forestry departments. You also may need some special planting tools. There are on-line specialty supply companies that provide equipment for natural resource managers. These forestry supply companies have a variety of planting equipment as well as other forestry equipment. So, the Tree is in the Ground... Things are pretty much out of your hands after the trees are planted. You have to leave things to Mother Nature. My experience has been that even when considering a freeze, insects, or fire, moisture is the most critical element in seedling survival for the first year or two. Trees and Drought is a short feature explaining the effect of the lack of moisture on trees, especially seedlings and saplings. Actually, most well-established trees will tolerate drought quite well, although much depends on the species and whether they are growing on an appropriate site.