Investigating the effect of different liquid densities on the time taken to release 25 ml of alcohols Essay Example for Free

Investigating the effect of different liquid densities on the time taken to release 25 ml of alcohols Essay * Research question: * Does the change in liquid densities at the same temperature affect the time taken to release 25 ml of the alcohol from a 50 ml burette? * Variables: * Independent variable: The liquid density / g ml-1. * Dependent variable: The time taken to release 25 ml of the alcohol from a burette / s. * Controlled variables: * The volume of alcohol in a burette / ml. * The temperature of the alcohols / oC. * The absence of unnecessary substances or ions. * The same burette for the entire experiment. * Prediction: * The time taken to release 25 ml of the alcohol from a 50 ml burette is, stated by F. Weinberg (1984) [1], dependent on flow velocity and in particular are very sensitive to small changes in the density difference between the two liquids. * My prediction is, the higher the liquid density is, the more time taken for 25 ml of the alcohol to be released from the burette. The time taken to release 25 ml of alcohol increases in order: Methanol, Ethanol, Propan-1-ol, Butan-1-ol and Octan-1-ol. * Method: * Apparatus: * 50 ml burette (Uncertainty: à ¯Ã‚ ¿Ã‚ ½ 0.500 ml). * Retort stand. * 125 ml ethanol C2H5OH 95.0%. * 125 ml methanol CH3OH 99.5%. * 125 ml propan-1-ol CH3(CH2)2OH 98%. * 125 ml butan-1-ol CH3(CH2)3OH 99%. * 125 ml octan-1-ol CH3(CH2)7OH 94%. * Thermometer (Uncertainty: à ¯Ã‚ ¿Ã‚ ½ 0.0500 oC). * 5 x funnels. * 50 ml conical flask. * Casio stop watch (Uncertainty: à ¯Ã‚ ¿Ã‚ ½ 0.0100 seconds). * Distilled water. * Risk assessment: * The procedure uses poisonous alcohols. Notably, suggested by Department of Chemistry Imperial College London (2006) [2], less than 2 teaspoons (2 ml) of methanol can cause blindness, and 2 table spoons (30 ml) can cause death. This toxicity is mainly due to it being converted in the body to formic acid and formaldehyde, which first attack the cells in the retina, then the other vital organs. Plus, propan-1-ol is used as a common solvent and cleaning agent in chemistry laboratories. Also, because it evaporates rapidly, IPA is widely used in astringents to cool the skin and constrict surface blood vessels. * Goggles and lab coat are therefore needed to be worn throughout the experiment. * Procedures: 1. Close the tap and run some distilled water into the top of the burette, then swish the burette up and down to let the water clean all the inside of the burette. Open the tap, let the water drain out. 2. Attach the burette to the retort stand and take care that the burette is upright and stable. 3. Close the tap and use the funnel to put 25 ml of ethanol into the burette. 4. Remove the funnel, make sure that there is no air bubble inside the burette. Measure the temperature of ethanol by the thermometer. 5. Put the conical flask under the burette, adjust the height of the burette so that the tip of the burette is just above the lip of the conical flask. 6. Open the tap and immediately start the stop watch. 7. Stop the watch when 25 ml of ethanol is fully released from the burette. 8. Continue to open the tap and collect the remained ethanol in the burette. 9. Repeat step 1 to 8 four more times. 10. Then change ethanol with methanol, propan-1-ol, butan-1-ol and octan-1-ol. Experiment step 1 9 with each alcohol. * Range and repetitions of experiment: * There are 5 different ranges (The lowest value: 0.789 g ml-1 the highest value: 0.826 g ml-1, Please refer to Data Collection and Processing - Processed data). * The initial procedure is repeated 5 times and thus 25 results are recorded. * Control of variables: * The volume of each alcohol sample remains constant for every test at 25 ml. Different volumes of the alcohol sample may cause inaccuracies in terms of measuring the time taken to release. For instance, larger volume of the same alcohol sample certainly takes longer time to be released. * The temperature of each alcohol sample need to remain constant for every test at 20 oC (293 K). The analysis, written by Weirauch, D. A., Jr. (1998, December) [3], of the high-temperature spreading kinetics for liquids affecting density shows that they can be modified with a constant shift factor. Therefore, higher temperature of the same alcohol sample may reduce the time taken for the alcohol to be released. * The burettes and funnels are rinsed carefully with distilled water prior to the experiment to ensure that inside the burettes do not contain any unnecessary substances/ions. If present, they may react with the alcohols to form products which have different liquid density, as opposed to original liquid densities of the alcohols at 20 oC (293 K). * The same burette is used for every measurement. This is because burettes from the same manufacturer cannot be guaranteed to have the same radius of the tips (possessing relatively small values). The use of different burettes can result differences in the time taken for the alcohol to be released. DATA COLLECTION AND PROCESSING * Raw data table: Alcohols Dependent independent variables Ethanol Methanol Propan-1-ol Butan-1-ol Octan-1-ol Liquid density / g ml-1 at 20 oC (293 K) [4] 0.789 0.791 0.804 0.810 0.826 1st repetition: Time taken to release 25 ml of alcohol from a burette / seconds à ¯Ã‚ ¿Ã‚ ½ 0.0100 39.0 43.0 67.0 82.0 112 2nd repetition: Time taken / seconds à ¯Ã‚ ¿Ã‚ ½ 0.0100 41.0 44.0 69.0 81.0 115 3rd repetition: Time taken / seconds à ¯Ã‚ ¿Ã‚ ½ 0.0100 38.0 46.0 70.0 83.0 111 4th repetition: Time taken / seconds à ¯Ã‚ ¿Ã‚ ½ 0.0100 39.0 42.0 71.0 80.0 114 5th repetition: Time taken / seconds à ¯Ã‚ ¿Ã‚ ½ 0.0100 40.0 45.0 70.0 79.0 110. Table 2.1 shows the collected raw data table. * Processed data: * Calculating the mean time taken to release 25 ml of alcohol from a burette: * Mean time taken / s = (1st + 2nd + 3rd + 4th + 5th trial data) à ¯Ã‚ ¿Ã‚ ½ 5. Alcohols Dependent independent variables Ethanol Methanol Propan-1-ol Butan-1-ol Octan-1-ol Liquid density / g ml-1 at 20 oC (293K). 0.789 0.791 0.804 0.810 0.826 The mean time taken to release 25 ml of alcohol from a burette / à ¯Ã‚ ¿Ã‚ ½ 0.0100 seconds 39.4 44.0 69.4 81.0 112 Table 2.2 shows the processed mean time taken to release 25 ml of alcohol from a burette. * Presentation of processed data: Graph 2.1 shows the relationship between the liquid density and the mean time taken to release 25 ml of each alcohol from a burette. * Treatment of uncertainties: * I try to read off carefully volume of the burette from the bottom of the meniscus with my eye level at the meniscus in order to make sure that the volume of each alcohol sample used is only 25 ml. CONCLUSION AND EVALUATION * Graph analysis: * According to the presented graph of the mean time taken to release 25 ml of different alcohols, there is a very strong positive correlation between the liquid density and the mean time taken to release 25 ml of alcohol from a burette as a very good line of best fit can be observed. (Please refer to Data Collection and Processing - Presentation of processed data - Image 2.1). * Conclusion: * The results demonstrate that, the higher the liquid density is, the longer time taken for 25 ml of the alcohol to be released from the burette. * The conclusion totally agrees with my hypothesis. * Evaluation of procedures: * Strengths: * Safety in the laboratory is highly maintained (by wearing goggles, lab coat and being careful with glass apparatus to avoid any poisonous alcohols that may splash). * Standard ranges and repetitions are met, a very strong positive correlation between the liquid density and the mean time taken to release 25 ml of alcohol from a burette is observed. * Quantitative investigation, with repeats strongly supporting each other, successfully proves that the expectations based on scientific knowledge are totally correct. * Weaknesses: * Several inevitable uncertainties occur throughout the whole experiment which may account for inaccuracies in the collected data. * The concentrations of the alcohols vary from 94.0 % to 99.5 %. The differences in concentration of each alcohol affect the reliability of the data, since 25 ml of pure alcohols (or 5 alcohols with the same concentration) may take different time to be released from the burette. * Although there is a very strong positive correlation between the liquid density and the mean time taken to release 25 ml of alcohol from a burette, the independent variables (liquid density) do not increase constantly due to the limited number of available alcohols (Please refer to Data Collection and Processing - Presentation of processed data - Image 2.1). * The entire procedures, although are simple, take a long time to finish because of the 50 ml burette need to take at least 3 times to add 5 alcohol samples (5 repetitions for each alcohol), 25 ml each. Overall there are 15 times to add 25 alcohol samples since I decide to investigate 5 different alcohols. The more time I need to add more alcohols into the burette, the more likely inaccuracies to occur. * Improving the investigation: * The procedures can be partially replaced by computer data logging suggested by Laurence Rogers (1995) [5] to prevent uncertainties from human errors when stopping the watch. The experiment can be programmed to collect the data (Time taken for 25 ml of the alcohol to be released from the burette) automatically. * More alcohols with liquid densities within the ranges (The lowest value: 0.789 g ml-1 the highest value: 0.826 g ml-1) can be tested to fill the 2 gaps between methanol and propan-1-ol, butan-1-ol and octan-1-ol in the presented graph. For instance, penta-1-ol has the liquid density of 0.815 g ml-1 at 20 oC (293 K) [6]. * Pure alcohols should be bought in the same concentration to ensure the reliability of the collected data. Otherwise, diluting the alcohols to the same concentration can be less expensive, yet time consuming. * A larger burette, for instance, with measuring volume of 75 ml (only 2 times to add 5 alcohol samples, 25 ml each) will reduce the times need to pour more alcohols into the burette to 10. Not only this change in equipment may save time of experimenting, but also minimise the uncertainties. Bibliography [1] Weinberg, F. (1984, December). Fluid flow from a low to a higher density liquid. Metallurgical and Materials Transactions B, 15(4), 681. Abstract retrieved March 8, 2009, from Springer Link. Web site: http://www.springerlink.com/content/n84726w432072592/ [2] Department of Chemistry. (2006, August 25). Biological effects of Methanol and Larger Alcohols. In Ethanol. Retrieved March 8, 2009, from Imperial College London. Web site: http://www.ch.ic.ac.uk/rzepa/mim/environmental/html/ethanol_text.htm [3] Weirauch, D. A., Jr. (1998, December). Predicting the spreading kinetics of high-temperature liquids on solid surfaces (Vol. 12). Alcoa Technical Center. Retrieved March 8, 2009. doi:10.1557/JMR.1998.0478 [4] Process Calculator. (2009). SG. In Liquid Density. Retrieved March 8, 2009, from Radix Business Models Pvt Ltd. Web site: http://www.processcalculator.com/Liquid_Density.aspx [5] Rogers, L. (1995, May). Sensors and The Data-Logger. In Hardware and software. Retrieved March 9, 2009, from School of Education, University of Leicester Web site: http://www.le.ac.uk/se/lto/logging/test1.html [6] Process Calculator. (2009). SG. In Liquid Density. Retrieved March 8, 2009, from Radix Business Models Pvt Ltd. Web site: http://www.processcalculator.com/Liquid_Density.aspx

Humor and Healing : The Mind Body Connection :: essays research papers fc

Humor and Healing: The Mind-Body Connection "As it is not proper to cure the eyes without the head, nor the head without the body; so neither is it proper to cure the body without the soul." —Socrates(Cousins, 56) The word, to heal, comes from the root word "haelen" which means to make whole. Bringing together the body, mind and spirit can be healing. The word humor itself is a word of many meanings. The root of the word is "umor" meaning liquid or fluid (Moyers, 221). In the Middle Ages, humor referred to an energy that was thought to relate to a body fluid and an emotional state. This energy was believed to determine health and disposition. In modern dictionaries, humor is defined as "the quality of being laughable or comical" or as "a state of mind, mood, spirit". Humor enhances the creative process and is one of the coping devices used to combat stress and disease. Humor can be used successfully in the classroom, in the workplace, in therapy and counseling, and in medicine to assist in the healing process (Cousins, 78). Laughter improves self-esteem, enhances social interaction, and generally makes life more enjoyable. Laughter can provide a cathartic release, a purifying of emotions and release of emotional tension. Laughter, crying, raging, and trembling are all cathartic activities which can unblock energy flow. Laughter is more than a visual and vocal behavior. It is accompanied by a wide range of physiological changes (Swencionis, 162). During vigorous laughter the body brings in extra oxygen, shudders the internal organs, causes muscles to contract, and activates the hypothalamus, pituitary, and adrenal glands. This results in an increase in the secretion of endorphins (internally produced morphine-like molecules). This â€Å"internal jogging† produces an increase in oxygen absorption, increase in heart rate, relaxation of the muscles, and increases in the number of disease fighting immune cells (Moyers, 230). Humor is a quality of perception that enables people to experience joy even when faced with adversity. â€Å"Stress is an adverse condition during which one may experience tension or fatigue, feel unpleasant emotions, and sometimes develop a sense of hopelessness or futility. Responding to these demands while protecting oneself from the potential harmful impact will help one to remain healthy† (Dreher, 27). Hans Selye, a pioneer researcher in psychosomatic medicine, defines stress as "the rate of wear and tear within the body" as it adapts to change or threat (Dreher, 20).

Emotions and memory Essay

In our everyday life, we rely on our memory to fully function. We either have to recall something so trivial such as where we left our keys, or we need to remember names of college classmates that we have not seen for a very long time. Given this fact, we ask, what exactly is memory, what are the processes involved in this cognitive function, and what are the factors that affect our memory? Memory is said to be the process and means by which we retain information and later on retrieve that same information from storage when we need it in the present (Bjorklund, Schneider, & Hernandez Blasi, 2003; Crowder, 1976; Tulving & Craik, 2000). When we experience something, we do not entirely store all the information in our memory. Studies show that there are different techniques that aid in adequate memory retention. There are also several dynamic theories about memory being a storage space for all our past experiences which involve sensory and informative data. Furthermore, there are also various processes through which we could access, recall, remember, or recognize these data in our memory. Although there are extensive research studies about memory and its processes, it is interesting to look at some factors that aid or hinder memory recall and retention. One of these factors which are given particular interest and attention is the role of emotion on our memory. There are instances when we recall a part of our memory in vivid clarity as if it is reenacted in our minds and retrieved in full detail. This is what we call flashbulb memory (Brown & Kulik, 1977). The reason behind this phenomenon is that the event that happened could be so emotionally powerful that it became strongly retained in our memory. In the event that you experience something that has a very strong emotional impact, you tend to remember the details more clearly and when you need to retrieve that certain information, you would be able to easily recall it accurately (Bohannon, 1988). This could manifest in both the explicit and implicit memory, with the former requiring the person to deliberately pull out the memory from storage and put it out in consciousness, and the latter being an automatic response to the emotional trigger. To further illustrate the capacity of affect to influence memory, a study was made by Heuer and Reisberg in 1990 which showed that materials which show more emotion than similar ones with less emotional impact are more likely to be stored in one’s memory and could be therefore retrieved easily in general and in detail as well (Christianson, 1992). Furthermore, it was also found that the mood or emotion where we were in when a specific situation happened would most likely serve as a retrieval cue when we experience the same mood in the present (Baddeley, 1989). For an instance, when we experience a certain situation when we are in a state of sadness, we would most likely remember the memory of the same experience when we are placed in the same emotional state. This is called the memory-dependent memory effects (Christianson, 1992). Biologically-speaking, the interaction between memory and affect could be attributed to certain processes in various parts of the brain. Brain processes involved in the evaluation of rewards and punishments are directly related to affect in the sense that it depends upon the emotional impact of a certain situation to be determined if it is a form of a compensation or a penalty (Rolls, 2000). Because of this, it could be inferred that since emotion influences memory processes, data-driven information and past situations are stored in our memory in the basis of a reward-punishment system. Essentially, when a certain event, person, place, or thing is categorized as something rewarding, it could be more easily encoded and retrieved. This categorization and selection happens in the amygdala, which is the center of emotional processing, and the data that get to pass through and be encoded encompass the mechanism in the hippocampus, which is on the other hand related to memory. Emotions disinhibit the barrier that the CA3 hippocampal area creates and so the data inputs could then proceed to the prefrontal cerebral cortex to be stored in memory (Neugebauer, et al. , 1999). It is also found in the study by Fast, et al. (1999) that the amygdaloid complex is primarily responsible with the emotional mechanism which affects memory retrieval. Subjects who have lesions in the amygdalo-hippocampal area do not only suffer from amnesia, but they also show significant impairments in memory process related with emotional arousal. The reason behind this is that the AC organizes the information that are encoded, stored, and retrieved in our memory. Another effect that emotion has on memory is what is called by Christianson (1992) as resource allocation effects, which is the impairment of the memory processing when a person experience an extreme or negative emotion or mood during encoding or retrieval. In this case, the person might find it difficult to access his/her memory of a certain situation, person, thing, or place because it has become a somewhat traumatic experience and the emotion that goes with it blocks the memory process. There are also some contradicting views that affect could not facilitate the retrieval or encoding of memory information. Some studies say that experiencing a negative emotion, for an instance, could prevent the person from remembering the details of a certain situation or event. This is the reason why most researchers focus on the determinants and factors which would tell what specific kind of data or information does emotion facilitate or impede. Although most of the existing studies focus on the effects of emotion on the memory processes, there are also some minor studies which show that memories of past experiences affect the present mood or emotional state of a person (Christianson, 1992). Though this angle is not yet looked at more closely by researchers, we most of the time experience this feeling, which we sometimes call nostalgia. Because memory and emotion are such complex topics when studied on their own, it is a more complicated feat to research on the interaction of the two concepts and their effect on each other. However, a lot of studies are being made in order to understand better these two psychological phenomena when they intertwine in their processes and how they affect the human psyche. References Baddeley, A. D. (1989). The psychology of remembering and forgetting. In T. Butler (Ed. ) Memory: History, culture and the mind. London: Basil Blackwell. Bjorklund, D. F. , Schneider, W., & Hernandez Blasi, C. (2003). Memory. In L. Nadel (Ed. ), Encyclopedia of cognitive science, 2, p. 1059-1065. Nature Publishing Group. Bohannon, J. (1988). Flashbulb memories for the space shuttle disaster: A tale of two theories. Cognition, 29(2), p. 179-196. Brown, R. & Kulik, J. (1977). Flashbulb memories. Cognition, 5, p. 73-99. Christianson, S. (1992). The handbook of emotion and memory: research and theory. Crowder, R. G. (1976). Principles of learning and memory. Erlbaum. Fast, K. , Fujiwara, E. , Grubich, C. , Markowitsch, H. J. , & Herrmann, M. (1999). Role of the amygdala in emotional memory. Memory and Emotion. p. 430. Neugebauer, A. , Calabrese, P. , Schmieder, K. , Harders, A. , Ferri, D. & Gehlen, W. (1999). Memory and emotion processing in healthy subjects, focal brain-damaged and patients with Alzheimer’s disease. Memory and Emotion. p. 113. Rolls, E. T. (2000). Precis of the brain and emotion. Behavioral and Brain Sciences. 23. p. 177-191. Sternberg, R. J. (2006). Cognitive psychology. Singapore: Thomson Wadsworth. Tulving, E. , & Craik, F. I. M. (Eds. ) (2000). The Oxford handbook of memory. New York: Oxford University Press.

Organic Farming The Eco System Super Hero - 2015 Words

Organic Farming: The Eco System Super Hero The agriculture farming industry needs to wake up and see the harm that conventional farming is doing to our beloved planet earth and realize that organic farming could be our planets superhero. Conventional farming uses a high level of nitrogen to help crops grow in mass production. These fertilizers sometimes get into the normal irrigation and eventually end up in rivers and oceans. A 2004 United Nations article estimated that most of the 160 million tons of nitrogen used as fertilizer annually ends up in the sea(â€Å"Conventional Farming†). Why is this bad? The fertilizer that ends up in the ocean creates algal blooms which have neurotoxins in them that suck the oxygen out of the water, creating†¦show more content†¦Pyrethrin is also used because it is biodegradable and can quickly be metabolized by birds and most mammals. The Organic Trade Association notes that if every farmer in the U.S. converted to organic production, we could eliminate 500 million pounds of persistent and harmful pesticides from entering the environment annually. Some of these harmful pesticides are called POPs short for Persistent Organic Pollutants. These pollutants are not only harming the planet, but they are also harmful to consumers. POPs are organic compounds that are able to survive in any form of the environment by living in other organisms. One of these pollutants is called Chlordane. In an article written by Dr. Edward Group titled â€Å"Health Dangers of Chlordane,† he explains how the chemical Chlordane is a man-made chemical that was used as a pesticide in the late 1940s and later banned in the late 1980s. The pesticide that conventional farmers in the U.S. we’re using on crops was also being used to control termites in houses. This pesticide, even though banned over 20 years ago, is still a problem in today’s society. Geological surveys have found that this pesticide is still in soil samples located in Yosemite National Park. This af fects the fish and wildlife that live in these areas because they drink or live in the water that has the contaminated soil. Once the wildlife in the area is contaminated and migrates, they spread the pesticide to other animals that may eat them.