Earth systems Essay Example | Topics and Well Written Essays - 1000 words

Earth systems - Essay Example posing a problem to the environment is the fact that the concentration of ozone in the ground-level is increasing while ozone in the stratospheric level is diminishing (Wright 774). This is a global environmental predicament because the stratospheric ozone has beneficial use while ground-level ozone produces detrimental effects. The stratospheric ozone layer was discovered sometime in the 1870s when scientists, led by G.M Dobson, observed the diminished amount of UV rays as they reach the earth’s surface, eventually attributing this phenomenon to ozone. By deduction, they concluded that the concentration of ozone in the upper atmosphere is higher than that nearer to the ground. A century later, it was discovered that certain elements could pose threat to this layer. When the US was planning to build supersonic transport planes (SST), studies revealed that the nitrogen oxide they would emit in the stratosphere layer, where they would be expected fly most of the time at a speed three times to that of sound and at an altitude of 12.4 miles, could destroy ozone (Konvicka 272). In the stratosphere, ozone is formed through a process called photolysis, when oxygen in the atmosphere is bombarded by solar UV radiation. This causes the two atoms of oxygen to split apart and merge with the atoms of other oxygen. The ozone gases then bond to form the ozone layer. This layer of ozone forms between 12 and 15 miles above the earth and protects it as well as life on it from dangerous UV solar radiation (Butz 376; Onursal et al 19). Ozone formation and destruction in the atmosphere occurs continuously and cyclically every time the UV rays of the sun act upon them, causing the breakdown of the gas and converting the resulting energy into heat. The heat raises the temperature at higher altitudes blocking the entry of the ultraviolet rays to the lower levels of the atmosphere. The split oxygen atoms then re-bond with the atoms of other oxygen to form new ozone. This continuous

The level of contamination on the things we use on daily basis Lab Report

The level of contamination on the things we use on daily basis - Lab Report Example The following tests were done: For Morphological test; culturing was done. The samples were cultured on MacConkey and r2a plate. These three items were compared to determine the level of contamination. After 24 hours of growth on both MacConkey and r2a plate, small growth was observed in all the samples. Similarly after 48 hours, large colonies were observed on both media for samples brush and Chap Stick but this was relatively higher on the brush. After undertaking Gram staining, it was observed that all the samples on both media had Gram positive bacteria. According to the result findings, the most probable bacteria identified were all cocci, bacilli, and spirilla. Besides, the brush sample seems to have high levels of contamination. These tests have been explored in the next section. Introduction By definition, Cross contamination is the transfer or physical movement of bacteria that are harmful from one place, person or object to another. It is a major factor which contributes to food poisoning, and it consists of 4 common sources that include people, work surfaces, food and equipment. Harmful bacteria live in or can be on our bodies, particularly around or on hands and faces as well as on clothing (McKillip, 2011). Due to the fact that they exist in small numbers they never cause a disease. If it happens that, there is a transfer of these bacteria from the clothes or bodies to food, and then given a chance to multiply, it can lead to food becoming unsafe to be eaten. Bacteria have the ability to multiply and live in any crevices and cracks in equipment including the chopping boards surface cuts. After using the equipment, food bits with bacteria can remain. If there is no proper cleaning of the equipment, there will be transfer of bacteria to another food when it is used next. Surfaces including bench tops might have bacteria on them as a result of contact with people, also dirty equipment, raw foods or other things like cartons stored on the floor can con tribute. If there is no proper cleaning of bench tops, there might be bacterial contamination of any food that is placed on them. The main objective of the study was to ascertain the level of cross-contamination on the thing we use on daily basis to make our faces that include brush, Chap Stick and mascaras. The experiment was conducted to test the amount of bacteria on the cosmetics we use daily. These products go to our face every time. Health is so critical and we need to give it a priority. The hypothesis of the experiment was that the brush had the highest level of contamination followed by Chap Stick then mascaras. Materials and methods Petri dishes Mascaras Brushes Chap sticks Method To begin the experiment there was a collection of the variety of cosmetics that included State brand and type od make up used. The next step was culturing as presented below; Culturing Techniques Incubation was done on agar media at of 37 oc . Streaked specimen using a loop, later flaming and coo ling was done, then streaked at 45o for a second time, this second streak over ­lap ­ped the first one.. There was less growth after 24 hours then after 24 hours a lot of growth was observed on both agar plate that was observed at 37 oc. There were large colonies, white in color, pink colonies, red colonies, circular in form, with margin that was filamentous Procedure for Tube method Five drops of 3% H2O2 was added to a 12 x 75-mm test tube. Small organism amount was collected with a wooden applicator stick from a ‘’well-isolated 18- to 24-hour colony’’ then it was put into the test tube. Care was taken not to pick up any agar. This is particularly crucial if the isolate of the colony was grown on agar that had red blood cells. The tube was Placed against a dark background and formation of immediate