«The purpose of this lab is as follows: To use mole ratios to predict the amount of precipitate formed, to use mole ratios to study the effect of reactant molarity on the yield of product, to use mole ratios to study limiting and excess reactants,...» Document abstract
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Language : english
physics & chemistry
case study
date published
26/09/2007
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SummaryThe purpose of this lab is as follows: To use mole ratios to predict the amount of precipitate formed, to use mole ratios to study the effect of reactant molarity on the yield of product, to use mole ratios to study limiting and excess reactants, and to design an experiment which achieves the above objectives.
The exact reacting ratio has to come into play when the two solutions are mixed. The molarity of the solution given must calculated before the experimentation process begins. One of the reactants will stay the same and the other one will change. This reactant will change in volume, thus being the independent variable. There will be a precipitate forming from the reaction of the two reactants. The molarity of the changing reactant is to be calculated. To do this, the concept of the exact reacting ratio should be comprehended. When two solutions are mixed and the ratio of their moles is perfect, this will be the exact reacting ratio. But when the ratio is not perfect (which in most cases it will not be) then one of the chemicals will be left over. It will not be fully used. The reactant that is fully used is called the limiting reacting because it is limiting the other reactant from fully reacting. The reactant that is not fully used up is the excess reactant. This one is left over. These concepts could be more easily grasped and understood through an example. How many hamburgers can you make with 8 buns and 5 pieces of meat? Only 5. In this case, the buns are the excess reactant because they will not be used up; the meat is the limiting reactant.
The exact reacting ratio has to come into play when the two solutions are mixed. The molarity of the solution given must calculated before the experimentation process begins. One of the reactants will stay the same and the other one will change. This reactant will change in volume, thus being the independent variable. There will be a precipitate forming from the reaction of the two reactants. The molarity of the changing reactant is to be calculated. To do this, the concept of the exact reacting ratio should be comprehended. When two solutions are mixed and the ratio of their moles is perfect, this will be the exact reacting ratio. But when the ratio is not perfect (which in most cases it will not be) then one of the chemicals will be left over. It will not be fully used. The reactant that is fully used is called the limiting reacting because it is limiting the other reactant from fully reacting. The reactant that is not fully used up is the excess reactant. This one is left over. These concepts could be more easily grasped and understood through an example. How many hamburgers can you make with 8 buns and 5 pieces of meat? Only 5. In this case, the buns are the excess reactant because they will not be used up; the meat is the limiting reactant.
Table of Contents- Purpose:
- Theory:
- Materials
- Procedure-
- Observations
- Experiment Errors
- Conclusion
- Sometimes the smallest occurrences are a big deal in chemistry and it is important to note them and acknowledge that they exist.
«Acid rain has always been said to damage the plant life which absorbs the acid water as it would regular water. In this experiment we have decided to see whether this is true and if acid content of water has any effect on plant growth. We have setup...» Document abstract
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4 word format
Language : english
biology
case study
date published
02/10/2007
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level : General public
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SummaryAcid rain has always been said to damage the plant life which absorbs the acid water as it would regular water. In this experiment we have decided to see whether this is true and if acid content of water has any effect on plant growth. We have setup an experiment and predict that pH will affect the height and leaf lengths of fast plants. Also we predict that the control will provide the largest plants.
Table of Contents- Introduction
- pH is a measure of the acidity or alkalinity of a solution.
- The Wisconsin Fast Plant (Brassica rapa) is a special breed of plant that was developed to be used in scientific experiments.
- Method
- Due to the short time allotted for this experiment, fast plants were used.
- Each group was grown in separate planting quads.
- Results
- It is important to note that certain plants did not grow, which meant less data was available.
- Discussion
- It is obvious that a pH concentration of 4 is ideal for plant growth, even thought the data for leaf lengths says otherwise.
- This experiment as well as the questions raised by it can be very helpful in acquiring an understanding of plant life
«The heart is probably one of the most important muscles in an organism’s body. It is what drives the flow of nutrients, oxygen, and other vital cells across an organism’s body. In different organisms the heart can have slightly different anatomical...» Document abstract
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3 word format
Language : english
biology
case study
date published
02/10/2007
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level : General public
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SummaryThe heart is probably one of the most important muscles in an organism’s body. It is what drives the flow of nutrients, oxygen, and other vital cells across an organism’s body. In different organisms the heart can have slightly different anatomical features as compared to other organisms. In humans, the heart is divided into 4 chambers; the left and right atriums as well as the left and right ventricles. Each chamber is separated by muscle walls and by special valves, the semi lunar and cuspids, which allow blood to flow into appropriate chambers and to make sure oxygenated blood and deoxygenated blood do not mix, allowing for 100% separation.
Table of Contents- The heart is probably one of the most important muscles in an organism's body.
- The blood in the frog heart gets pumped through the different chambers and throughout the body by contraction of the muscle cells in the heart.
- It can be said that the modern Internet began with the formation of several online communities.
- Modern medicine now uses technology which records the depolarization of the heart and graphs them allowing us to calculate heart rates and strengths.
- Although the heart is able to regulate itself, the nervous system is able to regulate the strength and duration of contractions.
- In this experiment we measured the mechanical and electrical activity of the Frog heart.
- Based exclusively on the data our hypothesis is supported, but it can not be applied because it was not carried out under optimal conditions.
«Our bodies and many other animals’ cells extracellular and intracellular fluids are mainly comprised of water with ionized salts in solution. These salts, mainly Na+, K+, Cl-, Ca2+, and Mg2+ ( Foundations Of Biology: Cell and Organ Physiology,...» Document abstract
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2 word format
Language : english
biology
case study
date published
02/10/2007
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SummaryOur bodies and many other animals’ cells extracellular and intracellular fluids are mainly comprised of water with ionized salts in solution. These salts, mainly Na+, K+, Cl-, Ca2+, and Mg2+ ( Foundations Of Biology: Cell and Organ Physiology, Faculty of the Department of Neurobiology and Behavior SUNY Stony Brook; Pacific Crest 2007, Lisle IL: pg 9) can appear in an organism in different times in varying amounts. Animals, including humans regulate the different concentrations of salt in their bodies versus the environment through osmosis, which is the movement of water molecules across a semipermeable membrane from a region of low solute potential to an area of high solute potential ( Wikipedia, the Free Encyclopedia, Wikimedia Foundation, Inc. Osmosis. http://en.wikipedia.org/wiki/Osmosis. Viewed 02/14/07).
Table of Contents- Introduction
- Our bodies and many other animals' cells extracellular and intracellular fluids are mainly comprised of water with ionized salts in solution.
- In this experiment, we used two organisms, Nereis virens, a worm which are usually found on floor of a shallow body of water, usually salt water.
- The worm on the other hand has no mechanism to regulate salinity, so when placed in a hypo osmotic environment the worms` cell would intake water and gain volume and not be able to release any, changing its internal salinity.
- Methods
- In our experiment we weren't able to obtain Nereis virens so there for preparing two watch glasses for each salinity was not needed
- The 500 ml was then split up between two groups running similar experiments, so that each watch glass still had 250 ml with the proper salt concentrations.
- Results
- Our results show, as seen in Figure 5, that at a 75% salt solution the clams have a slight decrease in weight while the worms have a significant increase in their weight.
- Discussion
- The experiment with the clams was conducted by us; however other problems might have contributed to the data.
«A human specimen can contain a number of involuntary responses (responses not consciously controlled) to outside stimuli; science calls this response a reflex. Some reflexes disappear as e mature into adults, such as suckling, grasp reflex, Moro...» Document abstract
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5 word format
Language : english
medical studies
case study
date published
02/10/2007
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level : General public
requested 14 times
SummaryA human specimen can contain a number of involuntary responses (responses not consciously controlled) to outside stimuli; science calls this response a reflex. Some reflexes disappear as e mature into adults, such as suckling, grasp reflex, Moro reflex and several others (Wikipedia, the Free Encyclopedia, Wikimedia Foundations, Inc. Reflex. http://en.wikipedia.org/wiki/Reflex#Significance, Viewed 04/22/07). Other reflexes, such as the knee jerk response stay with us for ever. Doctors use reflexes such as the knee jerk reflex, also called the Patellar Reflex, to see if the person’s sensory neurons, motor neurons and spinal cord are working properly.
Table of Contents- A human specimen can contain a number of involuntary responses (responses not consciously controlled) to outside stimuli; science calls this response a reflex.
- In this particular reflex, the tendon connected to the quadriceps is tapped causing the muscles of the quadriceps to stretch.
- Procedures were followed exactly as detailed in Foundations of Biology
- Based solely on our experiments our hypothesis for the Patellar reflex was confirmed.
- As with any experiment, human error can always influence results, making the conclusions not as apply able, especially since a small sample size was used.
«This experiment was conducted as a way to look at top-down, versus bottom-up processing. Subjects read the names of colors off Stroop boards, written first in a congruent color of ink, and next in an incongruent color. This allowed an opportunity to...» Document abstract
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2 word format
Language : english
psychology
case study
date published
03/10/2007
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level : General public
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SummaryThis experiment was conducted as a way to look at top-down, versus bottom-up processing. Subjects read the names of colors off Stroop boards, written first in a congruent color of ink, and next in an incongruent color. This allowed an opportunity to analyze the data and examine the differences between the congruent and incongruent conditions. This provides for a deeper look into the way people process information.
Many variations of this experiment have been performed, and have indicated that the incongruent condition significantly slows down processing. Subjects usually perform more slowly in the incongruent condition, and also make more mistakes.
Many variations of this experiment have been performed, and have indicated that the incongruent condition significantly slows down processing. Subjects usually perform more slowly in the incongruent condition, and also make more mistakes.
Table of Contents- Abstract
- Method
- Participants
- Materials
- Procedure
- Data Analysis
- Results
- Discussion
«Reflexes are the body’s involuntary responses to various stimuli. They are controlled in large part by the human nervous system which has three main functions: sensory input, integration, and motor output. Sensory input is due to sensory receptors...» Document abstract
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8 word format
Language : english
medical studies
case study
date published
09/10/2007
review : not yet assessed
level : General public
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Summary Reflexes are the body’s involuntary responses to various stimuli. They are controlled in large part by the human nervous system which has three main functions: sensory input, integration, and motor output. Sensory input is due to sensory receptors throughout the body collecting information about one’s external surroundings and internal environment, and relaying them to various information centers. A sensory receptor recognizes some form of stimulus in the external or internal environment and responds by creating graded potentials or action potentials in the cell or in the cell adjacent to it. These action potentials consequently lead to integration. Integration is mainly carried out within the Central Nervous System, which consists of the brain and spinal cord in humans. (Campbell, 1024) Motor output is what occurs when the central nervous system makes sense of the sensory input due to integration, and sends information to effector cells in the body. Effector cells are the gland cells or muscle cells that make sure the body’s responses to certain stimuli are carried out. (Campbell, 1024) Nerves conduct these signals. Specifically speaking, the particular nerves that relay the motor and sensory information from the central nervous system jointly make up what is called the peripheral nervous system.
Table of Contents- Introduction
- Reflexes are the body's involuntary responses to various stimuli.
- Neurons are the main unit of the nervous system.
- The whole process of a knee jerk reflex requires only three neurons.
- Results
- Table 2 shows the results of the first test, during which we delivered a tap to the patellar tendon with the hammer.
- In the third experiment on a human subject, we incorporated the Jendrassik maneuver.
- Two important terms to define are flexion and extension.
- Discussion
- Even though sources of error do exist, our results closely mimic our hypothesis.
- In the third experiment, we combined the use of the Jendrassik maneuver with the involuntary knee jerk reflex, once again striking the patellar tendon directly with the hammer.
- Negative feedback is the process where a change in a physiological variable triggers a response that counteracts the initial reaction.
«As living things, we are highly sensitive to changes in our environment; this doesn’t only mean changes outside our body, but changes from within also. For the cells in our bodies to function properly a certain temperature and pH has to be...» Document abstract
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2 word format
Language : english
physics & chemistry
case study
date published
09/10/2007
review : not yet assessed
level : General public
requested 5 times
SummaryAs living things, we are highly sensitive to changes in our environment; this doesn’t only mean changes outside our body, but changes from within also. For the cells in our bodies to function properly a certain temperature and pH has to be maintained. Even a slight change in pH inside our bodies can cause serious repercussions. Most of the fluids in our bodies range in pH from 6 to 8. Our body has buffers that maintain the pH of blood very close to 7.4 and we can not survive for more than a few minutes even the blood pH has changed slightly. Nature, to make sure homeostasis is maintained, has provided certain molecules that act as buffers. Buffers are molecules that absorb or release protons depending if the solution becomes more acidic (absorbs protons) or more basic (releases protons) (Miyazaki 4).
Table of Contents- Introduction
- A type of buffer that is used in many living system is the amino acid.
- Methods
- Results
- As predicted sodium chloride did not have any buffering capabilities.
«Many people are already indirectly familiar with the processes of fermentation, from the baker to the body builder. The baker, when baking his bread, adds yeasts that produces CO2, which makes the bread rise. Alcohol is also produced during this...» Document abstract
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2 word format
Language : english
biology
case study
date published
09/10/2007
review : not yet assessed
level : General public
requested 19 times
SummaryMany people are already indirectly familiar with the processes of fermentation, from the baker to the body builder. The baker, when baking his bread, adds yeasts that produces CO2, which makes the bread rise. Alcohol is also produced during this fermentation but it quickly evaporates during the baking process. When the body builder is exercising too hard your muscles need extra energy which they obtain from lactic cid fermentation and the cramps that are felt are from the access lactic acid that is the byproduct. Moreover, anaerobic respiration is also carried out by some types of fungi and bacteria when the supply of oxygen is not enough for regular cellular respiration.
Table of Contents- Introduction
- Both these processes start off with glycolysis, a process which is used in anaerobic environments, and end with the production of ATP.
- Based on the fact that the ratio of CO2 to ATP produced is 1:1, we can test the rate of ATP indirectly by looking at the rate of CO2.
- Methods
- Results
- Discussion
«The process of genetic transformation is an important tool used in biotechnology. It has been used in agriculture to create plants that are resistant to different kinds of conditions. In medicine it is being used to try and create bacteria that...» Document abstract
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2 word format
Language : english
medical studies
case study
date published
09/10/2007
review : not yet assessed
level : General public
requested 5 times
SummaryThe process of genetic transformation is an important tool used in biotechnology. It has been used in agriculture to create plants that are resistant to different kinds of conditions. In medicine it is being used to try and create bacteria that produce insulin which can be used to treat diabetes. Transformation can also e used to give bacteria the traits to digest oil, which then can be used to clean up oil spills. In nature transformation also accurse by itself, when suddenly bacteria become resistant to antibiotics, when they are introduced to it over and over. This happens because bacteria naturally share their DNA with each other which lets them adapt to the environment.
Table of Contents- The process of genetic transformation is an important tool used in biotechnology.
- In our experiments we had several variables that were available because of the pGLo plasmid.
- Our group obtained two Falcon tubes which we labeled +DNA for one and the other –DNA.
- The –DNA agar plates contained bacteria that were not introduced to the pGLo plasmids.
- The plate which had the arabinase had 85% of the colonies glowing under a UV light.
- Based on what we have done so far other experiments might be interesting to conduct based on similar settings.
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