Category: Experiment

Abstract

In this experiment, a laboratory test was carried out in order to separate plasminogen from horse serum. In this experiment, an activity chromatography method was used to separate plasminogen from horse serum using lysine sepharose. During the separation and purification, the extracted protein was divided into eight portions of which each portion was assayed at 280 nm optical density. From the results, its concluded that bands of high intensity are believed to contain high plasminogen which is evident by the level of absorbance (Silverstein, 1974). These eight portions were run on SDS- PAGE gel electrophoresis to separate isolated protein from further determination in this experiment; methods of analysis reported provide approximate determination of plasminogen.

In molecular biology, one of the major objectives is separation of a particular protein molecule from a complex of mixtures. This involves a number of steps of which each stage is monitored by electrophoresis to gauge its effectiveness. Chromatography is a technique used to separate molecules based on the differences in their chemicals and physical properties (Nieuwenhuizen and Traas, 1989). Chromatography lacks specificity for a single protein of which affinity chromatography is designed to overcome this limitation through exploitation of the distinctive interaction of a molecule with the next molecule which is a complementary binding molecule called ligand (Kline, 1953).This investigation concerns the purification step of plasminogen from horse serum involving lysine sepharose affinity chromatography. Plasminogen is the inactive precursor of plasmin and its essential in blood coagulation. The protein component is divided into several portions, of which each is assayed at 280nm of optical density measurement. These portions then undergo electrophonesis by being run through SDS-PAGE gel. SDS-PAGE separates isolated protein of which can be visualized by coo massive stain that binds to the experimental proteins and hence, the intensity of this resultant bands is used to give plasminogen estimation in a protein. A successful band is used to estimate the amount of plasminogen in a protein. A successful separation process is vital in classifying functions, protein structure and the relationship of plasminogen

Materials Provided

• Column: Affi-Gel Blue gel (BioRad)
• Protein Mixture: Horse Serum (Fisher Scientific)
• Column buffer: 10 Mm Tris-HCl, 150Mm NaCl, Ph 8.0
• Elution buffer:10 Mm Tris- HCl,150Mm NaCl, 1%SDS, Ph 8.0
• SDS-PAGE: 4-15% Tris-HCl Gradient ready-Gel (BioRad)
• Electrophoresis Buffers: Same as used for SDS-PAGE lab

Procedure

• The Affi-gel blue column was prepared. The Affi-gel blue is slurry containing the matrix and a buffer with preservatives.
• The slurry was poured into the column and equilibrated the column with the column buffer. Then column was secured by clamping to a ring stand. A porous disc in the bottom of the column retains the gel but lets solution and proteins flow through.
• A couple of ml of column buffer was put in the column, and then 2ml was transferred to the slurry column. The buffer was let to drip through into a beaker. Two layers begun to form, with the Affi-Gel Blue on the bottom and buffer on top. When the buffer approached the top of the gel layer, a column buffer was added to the column and allowed to flow through the column to be washed (Hatton and Regoeczi , 1975)
• The column material was not disturbed. Washing was repeated. Keeping the Affi-gel wet
• The bottom of the column was closed. 0.50ml sample of horse serum was prepared by diluting the serum 1:5 with column buffer. 20 ml of SDS-PAGE saved (Grant, 1990).
• To apply the sample, the buffer was allowed to drain to within 1-2mm of the top of the Affi-Gel Blue. Close off the column, and then carefully transferred 0.50ml of serum into the column. The flow was then collected (the solution containing protein that does not bind to the column).
• When the serum entered the column, the column was refilled with column buffer and washed the column. Collection of the flow was done until a total volume of about 1.5ml was obtained. The rest was discarded. The column buffer was rinsed to make sure all non-bound protein had been removed.
• When the final wash drained to about1-2mm of the top of the Affie-Gel Blue, 2ml of the elution buffer was carefully transferred into the column to remove the protein containing the albumin.
• The solution that elutes was collected (the bound protein) for SDS-PAGE. Washing the Affie-Gel Blue with about 10 ml of elution buffer was continued and then rinsed with about 10ml of column buffer. The Affie-Gel Blue was returned to be used used as Affie-Gel Blue.
• SDS-PAGE was performed onthe original serum sample, then flow-through/wash fraction, and the bound fraction carried out. Load 20mlof each sample, add 20ml reducing sample buffer, mixed well and boiled. Load 20 ml of each sample and 5 ml of the standards onto the gel, electrophoreses, stain and distain carried out.

Results

Discussion

Affinity chromatography provides room for fractional plasminogen distribution. In this process plasminogen and several forms of protein type are differentiated basing on the molecular size (Brockway and Castellino, 1971). From the results, it can be shown that the larger sized molecular proteins diffuse at slower rate compared to the smaller ones and hence this cover a shortest distance from origin. In this experiment, the size of the plasminogen has a smaller size of 92kDa (Swain, 1998):.The results reflects several sharp bands when separated by electrophoresis depending on the time limit running time for electrophoresis should be longer hence this is an indication of successful isolation of plasminogen from horse serum (Deutsch and Mertz, 1970)

Generally intensity of band is proportional to the amount of protein present in band which is also proportional to the amount of plasminogen at 280nm tube 3 are highest absorbance and its expected to contain at highest level of plasminogen while tube 8 gave the smallest absorbance, hence contains the smallest amount of plasminogen, the high absorbance rate obtained in the tube 4 may be due to great amount of undesired proteins (Williams et al, 1992)

References List

Brockway, W. J. and F. J. Castellino (1971): The mechanism of the inhibition of plasmin activity by aminocaproic acid. J. Biol. Chem. 246: 4641-4647.

Deutsch, D. G. and E. T. Mertz (1970): Plasminogen: Purification from human plasma by affinity chromatography. Science 170: 1095-1096.

Grant, A. J. (1990): Modifications to the lysine sepharose method of plasminogen purification which ensure plasmin-free Glu-plasminogen. Biochem Int. 20: 519 527.

Hatton, M. W. C. and E. Regoeczi (1974): Some of the observation on the affinity chromatography of rabbit plasminogen. Biochimica et Biophysica Acta 359: 55 56.

Hatton, M. W. C. and E. Regoeczi (1975): The relevance of the structure of lysine bound to sepharose for the affinity of rabbit plasminogen. Biochimica et Biophysica Acta 379: 504-511.

Kline, D. L. (1953): The purification and crystallization of plasminogen (profibrinolysin). J. Biol. Chem. 204: 949-956

Nieuwenhuizen, W. and D. W. Traas (1989):A rapid and simple method for the separation of four molecular forms of human plasminogen. Thromb Haemost 25: 208-210.

Ponting, C. P., J. M. Marshall, and S. A. Cederholm-Williams (1992):Plasminogen: a structural review. Blood Coag Fibrin 3: 605-614.

Silverstein, R. M. (1974): Ion exchange and affinity chromatography during the purification of human plasminogen on sepharose-L-lysine. Thrombosis Research 4: 675-686

Swain,W.R (1998): Plasminogen Assay. Clinical chemistry 14.262-272

Introduction

Steel is a valuable metal in civil engineering processes. The application of steel in these applications is attributed to its physical, chemical, electrical and mechanical properties (El-Reedy, 2017). Some of the mechanical properties of steel that determine its specific uses are hardness, tensile strength, elasticity, weldability and machinability (Bhaduri, 2018).

The mechanical properties of steel are determined by the chemical composition and manufacturing procedures. Therefore, steel may be processed differently to suit the requirements of various civil engineering applications that involve welding, drilling, forging, heat treatment and machining.

The expected Youngs modulus of steel should range between 190 and 210 GPa (Rao, 2017). Conversely, the maximum allowable value of yield strength is 650 MPa. Yield strength can be described as the tensile stress value where at least 95% of steel samples have a 90% likelihood of high yield strength.

Experimental Method

A piece of steel bar was provided for tensile testing. The sample was mounted in the grips of a Zwick Roell z250 testing machine that was controlled by the testExpert II software. An extensometer was mounted on the specimen to monitor the extension of the specimen. The test was continued until the specimen fractured. Load, extension and crosshead deflection were recorded by the software during the test and were converted by the software into stress and strain values. The outputs were used to compute parameters such as yield strength, ultimate tensile strength, 0.1% proof stress and Youngs modulus.

Results

Figure 1 shows the stress-strain curve that was obtained from the experiment. The yield strength was visualised on the curve as maximum stress just before a slight reduction. Its value was 540 MPa. The maximum strength recorded represented the ultimate tensile strength and was 622 MPa. The stress at the end of the experiment gave the breaking strength and was 504.56 MPa.

The stress-strain curve was re-plotted in the range of 0 to 1% strain to calculate Youngs modulus and 0.1% proof of stress, which is represented in Figure 2.

From figure 3, it is evident that the stress-strain relationship was linear to a strain of approximately 0.21%. Therefore, any two points between zero and this point could be used to compute Youngs modulus using the following equation:

Youngs modulus= Gradient of the straight-line section of the stress-strain curve

= y₂-y₁/x₂-x₁ where (x₁, y₁) and (x₂, y₂) are coordinates of two points on the straight line.

= (188.313- 18.3887)/ (0.0814096- 0.0042)

= 169.9243/ 0.0772096

= 2,201.04 MPa

= 2.201 GPa

The proof of stress was found by determining the point of intersection of the breaking strength point with the curve, which was approximately 435 MPa. A summary of the overall outcomes is provided in Table 1.

Table 1: Tensile stress outcomes.

Discussion

The observed value of Youngs modulus was 2.201 GPa, which was lower than the expected range of 190 and 215 GPa. This observation means that it had low elasticity and susceptible to distortion at low forces (Chen, Gandhi, Lee, & Wagoner, 2016). The observed yield strength was 540 MPa, which was within the expected limits given that the maximum allowable value is 650 MPa (Hajibagheri, Heidari, & Amini, 2019).

The experiment tested only one steel sample. Hence, the outcomes are not representative of the consistency of the entire batch from which the sample originated. There is a need to analyse more than one sample, conduct statistical evaluations of the outcomes before concluding whether or not the tensile properties are within the expected range.

Conclusion

Only one steel specimen was tested. The observed Youngs modulus was lower than expected. However, other tensile strength parameters matched the requirements of reinforcing steel. Additional testing should be done using more samples to ascertain the tensile properties.

References

Bhaduri, A. (2018). Mechanical properties and working of metals and alloys. Gateway East, Singapore: Springer Nature Singapore.

Chen, Z., Gandhi, U., Lee, J., & Wagoner, R. H. (2016). Variation and consistency of Youngs modulus in steel. Journal of Materials Processing Technology, 227, 227-243.

El-Reedy, M. A. (2017). Steel-reinforced concrete structures: Assessment and repair of corrosion. Boca Raton, FL: CRC Press.

Hajibagheri, H. R., Heidari, A., & Amini, R. (2019). Experimental relationship of yield and tensile strengths with hardness in high strength APIX70 steel pipes. Modares Mechanical Engineering, 19(1), 85-93.

Rao, P. D. (2017). Strength of materials: A practical approach (Vol. 1). Hyderabad, India: Universities Press.

Introduction

Plants are wonders and are of great nature and subject for several science projects. The growth of plants is affected by factors such as temperature, warmth, fertilizer, soil and light which can easily be manipulated. The scientific experiments become enjoyable, edifying and economical when plants are grown out of leaves, cuttings and different seedlings this in turn results to economically higher yields (Leonard, 1979, p.69).

Growing tomato seeds

Before sowing, moisturize the tomato seeds in warm water. No soil is required for the growing mixture best for starting tomato seeds. Sow the tomato seeds by burying them a quarter inch deep into the growing mixture. Tomato seeds should be sown deeply to avoid the drying up of the seeds before their germination in order to facilitate effective growth.

Once the tomato seeds have germinated that is after about six to eight weeks move the young seedlings and transplant them into the gardens where there is light. Delay in doing this could lead to transformation of the seedlings into undernourished plants as a result of over extension in an attempt to find sunlight. (Abdulla and Verkerk, 1968, p.12).

Young tomato plants grown from seeds require a minimum of six hours of direct sunlight to flourish. If finding sufficient source of sunlight is a problem the synthetic light sources like light bulbs can be installed taking into consideration that they are very much close to the tomato plant since they do not produce light to cover an extensive of area.

For example I planted three tomato plants using tomato seeds in one pot. After germination i.e. after six weeks I transplanted two seedlings. The first seedling was planted into a garden under a condition of strong direct sunlight of about six to eight hours daily and was far away from the light source. The second seedling was planted indoors and was provided with grow light of between fourteen to eighteen hours daily and was kept very close to the light source. The third seedling, I transplanted three weeks later in a garden situated under a shade.

Observation

The first seedling grew into a taller and thinner plant. The second seedling grew into a shorter and stronger plant. The third seedling, before being transplanted was trailing out of the pot and was undernourished and weak as a result of over-extension in trying to get sunlight. It had also developed some yellow leaves. After transplantation its growth was slow and stunted.

Questioning

• Do tomato plants grow towards light?
• What effect will delay in transferring the germinated tomato seed for transplantation have to the seedling?
• What effect does the amount of light have on the height of a tomato plant?

Hypothesis

Now that I have the questions in mind I can decide what the solution might be.

Tomato plants will turn towards the direction of light as they grow.

Delay in transferring the germinated young tomato plant to the garden leads to transformation of the seedling into a thin malnourished seedling as a result of over extension in trying to receive light which shows that the germinated plant is highly dependent on the light for its effective growth.

Tomato plants will grow taller and thinner when they are far away from the light and when there is less light intensity. Tomato plants grown indoors and kept close to the light source becomes shorter and stronger as a result of well nourishment (Wayands, 2003, p.22).

Testing

Having come up with the problem and the possible solution I can now test or design the experiment.

For example, carrying the test on the third seedling I transplanted it at the same time with the first two seeds i.e. after six weeks but keeping the light conditions under which it is planted constant. The time for transplanting is therefore going to be my variable.

Results

From the results, the tomato plants will turn towards the direction of the light as they are in their process of growth thus supporting the hypothesis.

Explanation

The explanation that addresses my question is as below. My question was the effect a delay in transplanting a young tomato seed has on the seedling and also whether tomato plants grow towards light.

The result of the test shows that when the third seedling was transplanted at the same time with the first two, it was not malnourished and had no yellow leaves. The seedling was not trailing out of the pot and therefore was strong. This shows that delayed transplantation makes the seedling to trail out of the pot in search of light making them thin and weary confirming therefore that tomato plants grow towards light (Leonard, 1979, p.71).

Conclusion

The experiment indeed proves that plants respond to light. From the test the hypothesis is supported. For instance when a seedling was not transplanted on time it trailed out of the pot in search of light, it was weak and some of its leaves had turned yellow due to lack of light.

Reference

Leornad, T. (1979). Understanding growth in the farm. Neth. J. Agric. Sci.16.69-72.

Abdulla, A.A. and Verkerk, K. (1968). Growth flowering and fruit-set of the tomato at higher temperature. Sci. 112: -12-14.

Wayands, G. (2003). Art and growth: Review of pollination and fruit set in the tomato Lycopersicon esculentum. Sci.12.22- 23.

In a research study, researchers have the mandate to use different types of search methods. In most cases, the nature of variables and the need of the investigation play a vital role in influencing the criteria for exploration. There are various approaches scientists can apply to analyze and examine the population sample. Each procedure presents its importance thus, investigators evaluate the one that fits with the objectives of the examination. The analysis focuses on exploring the variation between quasi and true experiments in the context of the research study.

Understanding quasi-experiments and True Experiments

Generally, quasi-experiment refers to a search study where researchers perform experimental research without randomly assigning the controls to the sampled population. The term Quasi means resemble; therefore, in these investigation, investigators manipulate the independent variables while the participants are not arbitrarily given conditions (Maciejewski, 2020). On the other hand, the true experiment is a type of study whereby the scientists make possible efforts to impose border controls on the sample population apart from the variable being studied (Leatherdale, 2019). In most cases, true experimental studies are conducted in laboratories where researchers have the ability to enact control. Figure 1 below highlights key differences between quasi and true experiments.

Case Study

Researcher conducted a study to determine and evaluate a new technique of teaching calculus to twelve graders. An investigator has two different classes to use for conducting the experiment. In this case, the analyst would perform the search using one class of twelve graders as a treatment group and another category of twelve graders as a control population sample. In this approach, the learners are not randomly assigned to the respective classes by the researcher, making the study be nonequivalent group design. This aspect implies that there is a high likelihood of significant difference amongst the students. For instance, some learners may have external influences such as parent motivation, thus excelling in calculus, or some students were allocated to a given class for disciplinary reasons. If the findings of the investigation indicate variation in calculus knowledge between the two classes, teaching methods or other variables may have caused the discrepancy.

In this research experiment, the random assignment does not completely eliminate the possibility of difference between the study groups but reduces it. Based on the hypothetical case study above, quasi-experimental research is appropriate because it provides higher internal validity (Athey & Imbens, 2022). Similarly, randomizing the students would not be easier; thus, applying the technique is effective to the search study. In addition, it is difficult to impose order control amongst the group since the students have the ability to interact and share calculus knowledge.

When the groups are categorized differently, it is easier for the researcher to explore the results of both classes and compare the outcomes. In the end, experimental investigation, the investigated class, and the control group are compared to effectively evaluate the difference between the two classes (Gage et al., 2019). This will allow the investigator to have deep insight into the causes of variation, thus prompting in developing the best approach to teach calculus.

Converting quasi-experiments and True Experiments

In summary, for the study to be converted into a true experiment, the researcher should formulate a way of grouping the students through randomization and also imposing a control group. Proper manipulation is necessary to understand the correlation between the variables (Miller et al., 2020). The control twelve graders are supposed not to receive any treatment to enable the investigator to identify the correct method of teaching calculus. The diagram below indicates some aspects of true experimentation that are necessary for the study.

References

Athey, S., & Imbens, G. W. (2022). Design-based analysis in difference-in-differences settings with staggered adoption.Journal of Econometrics, 226(1), 62-79. Web.

Gage, N. A., Grasley-Boy, N., Peshak George, H., Childs, K., & Kincaid, D. (2019). A quasi-experimental design analysis of the effects of school-wide positive behavior interventions and supports on discipline in Florida. Journal of Positive Behavior Interventions, 21(1), 50-61. Web.

Leatherdale, S. T. (2019). Natural experiment methodology for research: a review of how different methods can support real-world research. International Journal of Social Research Methodology, 22(1), 19-35. Web.

Maciejewski, M. L. (2020). Quasi-experimental design. Biostatistics & Epidemiology, 4(1), 38-47. Web.

Miller, C. J., Smith, S. N., & Pugatch, M. (2020). Experimental and quasi-experimental designs in implementation research.Psychiatry research, 283, 112452. Web.

Introduction

During my academic life, I have always observed that companies that use water as a heating medium prefer using steam to boiling water. This tendency has always amazed me since the boiling water and steam have the same temperature which is 100 degree Celsius. I have been arguing that if water and steam have the same temperature, none of them should be preferred to the other on basis of the heating capability. Additionally, I noted that after sweating, I feel cold for a moment although the ambient temperatures are very high. Based on these mysteries of nature I decided to investigate what happens during vaporization of water in order to explain the phenomenon. The figure below is a graph representing the heating curve of pure water where we observe that water maintains 100 degrees Celsius for a moment before turning to steam.

Conceptual Framework

There are concepts and theories that explain why steam is a better heating medium than boiling water although they might have the same temperature. Scientists argue that before substances change from liquids to gas, they absorb heat without showing increase in the temperature. This heat is hidden in a manner that it cannot be identified by increase in temperature implying that they are not even sensed by a thermometer. The hidden heat is referred to as the latent heat of vaporization since it is invisible to apparatus that detect changes in temperature. When the heat is measured per unit mass, which is mostly considered as one kilogram, the measure is referred to as the specific latent heat of vaporization. Various substances have different amounts of latent heat of vaporization since they have differing complexions. The table 1 shows the various substances along with their corresponding specific latent heat of vaporization.

Table 1: It shows the different substances along with their specific latent of vaporization.

From the table above, it is evident that water has a specific latent heat of vaporization of 2260kJ/Kg implying that the any mass of water absorbs heat that is proportional to this ratio (Lefrois, 1979). When calculating the amount that a mass of substance need to vaporize, we multiply the specific latent heat of vaporization with the mass.

Heat absorbed= Specific latent heat of vaporization x Mass of the vaporizing substance

Q= m x H_v

In this case, Q is the amount of heat absorbed, m represents the mass of substance which will evaporate, and H_v is the specific latent heat of vaporization of the substance. For example, when 0.3 kilograms of alcohol is evaporating it absorbs 256.5 kJ of heat. This is obtained by multiplying 855 kJ/Kg by 0.3 Kilograms.

Q= 855 kJ/Kg x 0.3 Kgs = 256.5 Kilojoules

Risks and Risk Control

There are various risks that are conjoined with this experiment due to the technicality of the experiments. This list below shows the risks and how they will be controlled.

• Since the experiment involves heating water the steam might burn inflicting injuries on the body. Additionally, the hot apparatus might cause burns on the skin leading to pain and wound. In order to control this risk, holders will be used ensuring that the apparatus are not held with bare hands.
• Secondly, the apparatus might break due to when heating especially if they experience temperature imbalances. In this case, hot apparatus that are made of glass will not be washed using cold water before they cold down. Thermometer will be kept in their bags when they are not in use.
• Lastly, spillage of water on the floor might make the floor become wet and lead to slipping that can cause adverse bodily injuries. Lags will be used to wipe the floor and benches ensuring there is not water on the floors.

Experiment Procedures and Requirements

This experiment needs an electrical heater, a boiling trough, one stop watch, and a balance for measuring mass.

Procedure

• Set up the tools that are described above as shown in figure 2 in order to set for the experiment.

• Measure the original mass of the boiling trough, water and the heater. Record this mass as M1.
• Identify the heaters watt and record it as W.
• Immerse the heater in the water and put on the heater
• Start the watch when the water starts boiling and not before it boils.
• Record the mass of the trough and water after every three minutes. This should be recorded on the M2 column.
• The time should be recorded besides the time column
• Record the data in table 2 which is shown below.
  • M1=
  • W=

• Calculate the mass of evaporated liquid by subtracting M2 from M1 and record this on the corresponding column.

During calculation, it should be considered that the heat releases during by the heater is equal to the heat that is absorbed by the water and trough.

(W_heater) x Time = m x H_v.

Therefore, the specific latent heat of vaporization can be obtained by making the subject of the above formula and compute the result.

H_v = ((W_heater) x Time)/m

Results Obtained and Analysis

M1=1030 g

W= 126 J/s

Taking the first data set of the results that were obtained we can calculate the latent heat of vaporization.

P= W x t

P= 126 x 180s = 22680

Hv = 22680/ 10= 2268 j/Kg

We can find the average by adding all the value of latent heat and dividing by three. (2268+2061+1890)/3= 2073 J/Kg

This value could be compared with the theoretical value which is 2260 J/Kg. However, there is a significant error that is reflected on the value. This error is attributed to the prevailing temperature conditions that could have caused loss of heat to the surrounding environment. Additionally, draught might have affected the results since it additionally cause the loss of heat (Hunter, 1997). Lastly, the error might have been caused due to some impurities which could be found in the water implying that the water was not pure during experiment. This implies that the amount of heat required for heating and vaporization might have been lower than the common. However, the valued can be relied on since it is on the range of error that is associated with the latent heat of vaporization in this experiment.

Uncertainties

• The power of the heater was not uncertain since the reading was not obtained directly from the heater
• Uncertainty of beam balance was +/- 1gram
• Uncertainty of time was +/- 0.1 s
• The uncertainty of the latent heat of vaporization is obtained by adding up all the results and finding the average. This could be

Explanations

From the above experience, it is evident that water absorbs a hidden amount of energy so that it can vaporize and change its state of matter from liquid to steam. However, this heat is not visible since thermometer does not show difference temperature. This scenario explains why the steam is a better heating medium that the boiling water. In this case, steam absorbs latent heat of vaporization enabling it to have more heat than the boiling water. According to my experiment, 1 gram of steam could have additional 2273 joules of heat more than boiling water which is at the same temperature. This implies that it produce more heat than the boiling water, in the same light, when the steam cools down it releases this heat which is absorbed by the object which is being heated by the medium. On the other hand, boiling water would only have the heat that enabled it to reach 100 degree Celsius.

The same explanation can be used to explain why I feel cold when I am sweating during a hot day. In this case, the sweat contains water that is the main component of sweat from the body. On a hot day, high temperature make the water on the skin to evaporate to the atmosphere. As the water evaporates, it absorbs the latent heat of vaporization from the body. This absorption of heat form the body makes the skin to feel cold for a moment. Consequently, the latent heat of vaporization becomes crucial when cooling object. In fact, the cooling systems that use water use the same principle of latent heat of vaporization. In this case, water gets into contact with the hot metals that make the cooling system. Water is heated up to 100 degree Celsius leading where it vaporizes. During vaporization, it absorbs the latent heat of vaporization according to the mass of water that is used for cooling. This heat reduces the amount of heat which was originally in the system resulting to cooler temperatures than the ones which were originally in the machine.

Conclusion

According to this experiment, the latent heat of vaporization is estimated to be 2073J/ Kg which is roughly accurate as compared to the theoretical values that is 2260J/Kg. it shows that water absorbs hidden amount of heat that is not detectable on a thermometer since it does not cause change in temperature. This heat makes steam a better heating medium than boiling water where steaming is one of the best cooking methods. It, also, explains why people feel cold when sweat evaporates from the skin on a hot day. Additionally, the concept explains the ability of water to act as a cooling liquid in machine since it absorbs the latent heat of vaporization causing reduction in temperature (Wilson & Hall, 2005).

References

Bellium, A, Specific Latent Heat of Vaporization, Home Page.

Hunter, C, 1997, Latent heat, Winnipeg, Man, Nuage Editions.

Lefrois, R, 1979. Active heat exchange system development for latent heat thermal energy storage, Washington, Dept. of Energy, Office of Energy Technology, Division of Energy Storage.

Kent, W,. Heat of Vaporization, Mr. Kents Physics Regents Help and AP Physics Exam Review Pages.

Wilson, J, & Hall, 2005, Physics laboratory experiments (6th ed.), Boston, Houghton Mifflin.

Introduction

The essence of performing this experiment was to verify the relationship between the effects of force on the extension of a coiled spring and as such, verify the principle behind a spring balance.

The experiment was approached courtesy of a vertically mounted panel upon which two springs, one under compression and the other under extension, were suspended and subjected to their respective forces and their corresponding changes in length recorded for analysis. The essence was to subject these two springs under the force of gravity and as such draw a correlation between the change in length and the applied force. Consequently, this relationship would aid in understanding the principle behind the calibration of a spring balance.

From the experiment, it was clear that both the compressed and the extended springs changed their lengths proportionately with the change in the applied forces. Hence, the springs obeyed Hookes law for elastic materials. This principle is the basis for spring balance calibration.

Experimental Objective

The objective of this experiment was to verify the relationship between the effects of force on the extension of a coiled spring and as such, verify the principle behind a spring balance.

Theoretical Background

When a coiled spring is subjected to either extension or compression forces, it will extend or compress respectively. With the status quo, the spring possesses some energy vital in the construction of equipment that displays cushioning effects under stress. Among the equipment are shock-absorbers, buffers and engine values. Besides displaying cushioning effects, a coiled spring is understood to be the single most important element of a spring balance (Slaughter 9). Under varied extension forces, the extension of a coiled spring is understood to be proportional to the same. As such, designers of spring balances selectively design spring balances for measuring weights within a certain bracket. This is so because beyond some critical value of the weight the spring balance ceases to be effective. For this reason, a spring balance intended for measuring heavy loads makes use of stiffer springs that are less sensitive to lighter loads. On the contrary, spring balances intended for measuring lighter loads makes use of more sensitive springs.

In order for a coiled spring to be used to measure weights of different bodies, they need to be calibrated to give accurate measurements. The relationship between the stretching force and the extension is understood to be proportionate within the stretching limit. This is explained by Hookes law which states that for an elastic material, the stretching force is directly proportional to the stretching force as long as the elastic limit is not exceeded. Correspondingly, when the spring is subjected to compression force it obeys Hookes law (Slaughter 10). The correlation between the stretching force and the extension means that a spring balance traces a uniform scale. This principle forms the basis for calibration for spring balances.

Experimental Procedures

In the first experimental setup, a mounting panel was mounted vertically upon which a stretching spring was suspended ready for analysis. A weight hook was later hung at the lower end of the spring ready for suspending weights. A piece of paper was then mounted on the mounting panel such that the position of the hook is biased at the top of the page. The lower level of the hook was marked against the paper using a pencil and a set square. A 1N weight was later hung on the hook after which the lower end of the hook was marked against the paper. The weight and its corresponding extension were recorded for analysis. A 1N weight was added one at a time as their corresponding extensions were being recorded. These were added to a maximum of 5N and later used for analysis. Upon reaching the 5N mark, the reverse was done to confirm that the marks coincide.

In the second setup, the initial spring was replaced by a shorter one while maintaining the step-by-step procedure of the same. In the third setup, however; the arrangement was the reverse in that it was based on compression rather than an extension. 1N weight was added one at a time just like the previous experiment after which off-loading was done step by step.

Experimental Data

The data obtained from the experiment is as shown below:

Table 1 for the first test (long spring);

Table 2 for the second test (shorter spring);

Table 3 for compressed spring;

Data Analysis

According to Hookes law;

Force (F) is directly proportional to the extension (e).

Therefore,

F e hence,

F=ke

k is the spring constant which depends on the stiffness of the spring.

On plotting F against e, a straight line is obtained:

The first test:

Graph 1 of Force against an extension for the long spring:

F= ke

K (spring constant)= gradient= (change in force)/(change in extension)= 50 N/M

Therefore; F=50e

The second test;

Graph 2 of Force against an extension for the shorter spring:

k=9.09N/M

Therefore; F=9.09e.

Test 3 for compressing spring.

Graph 3 of force against extension:

k=20N/M

Therefore; F=20e.

Discussion

The objective of this experiment was to verify the relationship between applied force and extension for a coiled spring subjected under either compression or extension forces. According to Hookes law, the relationship between the two ought to trace a linear relationship. As such, the force should be directly proportional to the extension as long as the elastic limit is not exceeded. The constant of proportionality, k, determines the strength of a spring balance. On comparing the strengths of springs, the strength increases with the increase in the value of k. For this reason, a strong spring is meant for weighing heavier loads while the opposite is meant for lighter loads.

On comparing the plots of the graphs for the springs it is clear that they obey Hookes law. Thus, from the three graphs, it is clear that the applied force is directly proportional to the extension. This principle comes in handy when calibrating springs. From the calculated values of kit is evident that the longer spring is the strongest (K=50N/M) while the shorter one (k=9.09N/M) is the weakest of the three. The corresponding values of loading and offloading might not be the same because of some slight deformation experienced during loading. For this reason, when using a spring balance to measure weights of loads, it is vital that the values of k be monitored to ensure it is constant to obtain consistent results.

At some point, one would be required to substitute a spring with a new and similar one to maintain consistency. The difference between springs designed for weighing a 1N load and a 1KN load comes in the degree of stiffness numerically illustrated by the bigness in the values of k. Hence, the latter will have a higher value of k than the former.

Conclusions

The main objective of this experiment was to draw a relationship between applied force and the extension of a coiled spring. The relationship was proportionate meaning that the spring extends uniformly with the increase in force. This principle forms the basis behind the calibration of spring balances.

Works Cited

Slaughter, William. The Linearized Theory of Elasticity. Cambridge: Cambridge University Press, 2002. Print.

Results

Comparison between Different Concentrations

The results indicated that the number of germinated seeds differed according to the concentration of solutions. The results of CaCl₂ showed that the seeds placed in 0.0625M CaCl₂ germinated quickly on the second day and attained the mean of about 10 germinated seeds on the seventh day while the ones placed in 0.125M CaCl₂ delayed germinating and attained about three as the mean number of germinated seeds on the seventh day.

The results of KCl indicated that the seeds placed in 0.125M KCl germinated earlier on the first day than the ones placed in 0.0625M that germinated later on the second day. In the seeds grown in MgCl_{2, a} comparison of results showed that seeds in 0.0625M solution started to germinate on the second day while ones placed in 0.125M solution delayed and germinated on the third day. The results of NaCl showed that seeds in both 0.0625M and 0.125M solutions germinated on the second day and attained approximately the same mean number of germinated seeds on the seventh day.

Comparison between Different Solutions

Furthermore, the results showed that the number of germinated seeds varied as per the type of solutions. A comparison of results reveals that seeds in KCl started to germinate on the first day while seeds in CaCl_2, MgCl_2, and control solutions started to germinate on the second day. In contrast, seeds in NaCl started to germinate on the third day. Relatively, approximately the same mean number of seeds had germinated in KCl, NaCl, and control solutions on the third day. On the contrary, the mean number of germinated seeds was the lowest in seeds in CaCl₂ solution followed by the mean number of seeds in MgCl₂ solution.

On the fourth day through to the seventh day, the mean number of germinated seeds depicted a similar trend in MgCl₂, NaCl, KCl, and control solutions. Comparatively, the results revealed that seeds in KCl, MgCl₂, NaCl, and control solutions had about the same mean number of germinated seeds whereas seeds in CaCl₂ had the lowest mean number of the germinated seeds.

Discussion

The objective of the experiment was to ascertain how different solutions influence the germination of seeds. Essentially, the nature and concentration of solutions influence osmosis, which in turn affects the rate of seed germination (Mirzaei et al. 1090). The results showed that a high concentration of CaCl₂ inhibits germination of seeds while a low concentration stimulates growth. Regarding the concentration of KCl, the results indicated that low concentration hastens the germination rate of seeds. In the aspect of MgCl₂, the results revealed that a high concentration slows down the germination rate of seeds. The results also showed that a low concentration of NaCl hastens the germination rate of seeds.

As osmosis is a physiological process, which explains the effect of solutions concentration on the germination of seeds, Bojovic et al. explain that inorganic ions in solutions reduce the osmotic potential of seeds and hinder effective absorption of water for germination purposes (83). Seeds grown in solutions germinate at a slower rate or fail to germinate when compared to seeds grown in distilled water.

The results demonstrated that seeds grown in the solutions of CaCl₂ and MgCl₂ with high concentration had slowed germination rate or inhibited germination when compared to other solutions. These findings are consistent with the findings of a study, which established that the inhibition effect was higher in the solutions with MgCl₂ and CaCl₂ when compared to solutions with NaCl and KCl (Panuccio et al. 5). The plausible explanation of the apparent observation is that divalent cations induce more osmotic stress than monovalent ions.

Moreover, from the results, it is apparent that seeds grown in different solutions did grow at different rates, but eventually achieved about the same number of germinated seeds. Rapid germination rate observed occurred because monovalent ions do not induce significant osmotic pressure on seeds, and thus, allowing them to imbibe water fast and germinate rapidly. In saline conditions, seeds take a long to germinate because the osmotic stress slows down the process of water imbibition resulting in the delayed breaking of dormancy (Demir and Mavi 899). Eventually, seeds manage to germinate even in the most saline environment because seeds imbibe water slowly until they get adequate amounts for breaking their dormancy.

According to other studies, the presence of cations, such as Mg²⁺, Na⁺, Ca²⁺, and K⁺, in water reduces the germination rate of seeds because they create physiological drought and prevent or delay seeds from breaking their dormancy (Abari et al. 53; Mirzaei et al. 1090; Zhang, Rue, and Wang 528). The findings of this study are similar to other studies because the design of the experiment ensured that the findings are valid and reliable. Therefore, the findings support the hypothesis that the rate of germination in seeds grown in solutions is slower than the rate of germination in seeds grown in distilled water.

As the experiment used two concentrations of a given solution and three replicates, the outcomes do not provide robust results. In this view, a follow-up experiment should expand the range of solutions, and the number of replicates to provide a clear trend of variation in the germination. Moreover, there is a possibility that the experimental design led to biased outcomes for each student recorded own data. Hence, a blinded study is appropriate to prevent researchers from introducing their biases into findings.

In conclusion, the experiment has demonstrated that a high concentration of CaCl₂ and MgCl₂ inhibits germination while a high concentration of KCl and NaCl slows down the rate of germination.

Works Cited

Abari, Akram, Mohammad Nasr, Mohammad Hojjati, and Dariush Bayat. Salt effects on seed germination and seedling emergence of two Acacia species. African Journal of Plant Science 5.1 (2011): 52-56. Web.

Bojovic, Biljana, Gorica Delic, Marina Topuzovic, and Milan Stankovic. Effects of NaCl on seed germination in some species from families Brassicacea and Solanaceae. Kragujavac Journal Science 32.1 (2010): 83-87. Web.

Demir, Ibrahim and Kazim Mavi. Effect of salt and osmotic stresses on the germination of pepper seeds of different maturation stages. Brazilian Archives of Biology and Technology 51.5 (2008): 897-902. Web.

Mirzaei, Amir, Rahim Naseri, Tahereh Emami, and Askar Jozeyan. Effect of salinity on germination and seedling growth of bread wheat (Triticum aestivum L.). International Journal of Agriculture and Crop Sciences 4.15 (2012): 1089-1091. Web.

Panuccio, Maria, Erik Jacobsen, Shoaib Akhtar, and Adele Muscolol. Effect of saline water on seed germination and early seedling growth of the halophyte quinoa. Annals of Botany Plants 6.47 (2014): 1-18. Web.

Zhang, Qi, Kevin Rue, and Sheng Wang. Salinity effect on seed germination and growth of two warm-season native grass species. Horticulture Science 47.4 (2012): 527-530. Web.

Introduction

The objective of this experiment is to determine the amounts of the component parts of hydrated copper (II) Sulfate. These components are: water, sulfate ions and copper ions. The experiment aims at determining the empirical formula of hydrated copper (II) sulfate. Empirical formula is the smallest numeral ratio of atoms that are in a compound. Gravimetric analysis is the methodology that will be used in determining the empirical formula of copper (II) sulfate. In this methodology, the compound being analyzed is reacted with another substance to form a solid compound. The reaction employed is such that it is possible to know the components of the products.

Three procedures are performed in this experiment and the first one is the analysis of the copper ions. Here, the hydrated copper (II) sulfate is reacted with oxine to form a complex called copper (II). Because we know the makeup of the complex we can get the amount of copper ions that were in the initial sample of the copper sulfate (hydrated).In getting amount of water in the hydrated copper (II) sulfate a sample is heated to drive off all the water. The water present is the difference in mass, if the sample mass is measured before heating and after heating. The third procedure is the scrutiny of sulfate ion in a sample of copper sulfate (hydrated). Here, the hydrated copper sulfate is reacted with barium chloride to form barium sulfate.

Experimental methods

Scrutiny of copper ions by precipitating the hydrated copper (II) sulfate with oxine

Oxine is an 8-hydroxy-quinoline organic compound. When reacted with Cu (II) or other metallic ions it behaves like a monoprotic acid and a metal complex is formed. The composition of the complex formed when hydrated copper (II) sulfate is reacted with oxine is Cu (C₉H₆ON) ₂ with 351.85g/mole formula weight.

The following steps are followed:

1. Approximately 3g hydrated copper sulfate is weighed to the closest milligram.
2. The copper sulfate is dissolved in 100ml of water that is distilled and contained in a big beaker.
3. 5ml of acetic acid (glacial) is added and 1.5g of ammonium acetate is also added.
4. The solution is heated in a hot plate toward approximately 75⁰C.
5. 3% oxine (in ethanol and water in the ratio 95:5) is added drop wise while stirring awaiting completion of the precipitation and the reagent is in excess. Approximately 17-20 milliliters of the oxine solution are needed for this experiment.
6. For 5 minutes, and at 65-70⁰C the mixture is heated and then stirred vigorously, after which the precipitate is allowed to settle. If adequate reagent is used the resultant liquid will be orange-yellow or yellow in color.
7. A filter paper is folded and weighed and a beaker is labeled with grease pencil.
8. The filter paper is placed in a glass funnel placed on an Erlenmeyer flask.
9. A large amount of the liquid is decanted into the filter set up. The remaining mixture is stirred and filtered.
10. Using hot water the residue and the beaker are washed.
11. A rubber policeman is used to scrub the beaker.
12. The residue is transferred to a small beaker or casserole which is dry, clean and has been weighed previously.
13. The beaker or casserole is covered with aluminum foil which is perforated and the system is allowed to dry.
14. Weight of product, after drying is used to get the percentage of copper.

Determination of the amount of water in hydrated copper (II) sulfate.

In this experiment, care should be taken because crucibles that are cold and those that are hot look alike.

Steps to be followed are:

1. For 5 minutes a clean, dry crucible is heated on the stand apparatus and then allowed to cool.
2. The crucible is weighed.
3. By a difference of 2g, hydrated copper sulfate is weighed into the crucible.
4. The system is returned on the clay triangle. The lid is kept such that the crucible is partially covered.
5. The crucible is heated gently on a small flame.
6. In the heating process the material is stirred periodically.
7. 15 minutes after heating the system the crucible is covered completely and allowed to cool.
8. The crucible and its contents are weighed after they are cooled and the lid removed.
9. For 5 minutes the system is heated once again and allowed to cool.
10. The crucible is weighed when cool, and still covered.
11. The procedure is repeated until consecutive weighing does not fluctuate by more than a centigram.
12. The data is used to calculate the amount of water in hydrated copper sulfate.

Data and results

1. Part A data
   1. Copper sulfate hydrate: 0.307 grams
   2. Filter paper: 0.806 grams
   3. Weight of product (precipitate):1.296 grams
2. Calculation of the percent of copper ions in hydrated copper sulfate
   1. Mass of Cu in Cu (C₉H₆NO) ₂
   2. M=0.089
3. Part B Data
   1. Crucible Wight: 25.457
   2. Crucible + copper sulfate hydrate: 27.748 grams
   3. Cool crucible Wight: 26.748 grams
   4. Crucible Wight after heating then cooling again: 26.755 grams
4. Calculation of the amount of water in hydrated copper sulfate
   1. Mass of H₂O= 0.702grams
   2. % of H₂O= 35.1%
5. Calculation of the amount of sulfate in hydrated copper sulfate
   1. SO₄ %= 36.07%
   2. The empirical formula of copper sulfate hydrate is Cu SO₄. 5H₂O

Errors in the experiment

1. (Errors when getting the percent of copper ions in copper sulfate.
   1. The calculated percentage of the cation would have increased if he mass of the precipitate had been too high.
   2. The possible reason that too much precipitate might be collected in the lab is the existence of foreign cations for example ferric iron and calcium which are co-precipitated.
   3. If the mass of the precipitate had been too low the percentage of the cation would have reduced.
   4. Some of the possible reason why too little precipitate may be collected in the lab is that the substance to be weighed is not readily removable by filtration
2. Errors when getting the amount of water in hydrated copper sulfate
   1. If the mass of the heated crucible had been too high the calculated amount of water would have reduced.
   2. One reason why the mass of the crucible after heating could be too high is the failure to remove all the water from the hydrate.
   3. If the mass of the heated crucible had been too low the calculated percentage of water would have increased.
   4. A reason why the mass of the crucible after heating could be too low is decomposition of the hydrated copper (II) sulfate by overheating.

This laboratory experiment focuses on the chemical composition of cells, appropriate identification of which contributes to the understanding of distinctions between organic and inorganic chemicals. By utilizing iodine and emulsifiers tests  in the framework of both negative and positive control experiments  hydrophilic or hydrophobic oxygen content of a chemical will be identified in the laboratory setting (Cheng et al., 2017). Such an approach has been chosen in order to gain a full-scale practical comprehension of the essential topic. The experiment deals with many variables and should be prepared thoroughly. It should be noted that this experiment requires a substantial preparation within the safety scope, and thus is supervised by an experienced instructor.

After the accomplishment of this activity, there will be enough practical skills and knowledge to explain the relationship between starch, fiber, and complex carbohydrates and how they relate to glucose, sugar, and simple sugars. In order to achieve this, iodine and emulsifier  as mentioned above  will be applied. The experiment with the latter will show that hydrophobic chemicals (like fat and other lipids) do not mix with water  if an emulsifier is present, the fats will stay mixed with the water. Then, an iodine experiment will reveal that iodine turns blue-black in the presence of starch, but not fiber.

Hence, the primary purpose of this laboratory experiment might be formulated as follows. The obtained knowledge and experience are to serve as a vital background for understanding the essence of organic and inorganic chemicals, as well as to be able to sort out hydrophilic and hydrophobic characteristics. At this point, it seems reasonable to present the following methodology and materials that were applied to achieve the given purpose.

Reference

Cheng, L, Guo, H., Gu, Z., Li, Z., & Hong, Y. (2017). Effects of compound emulsifiers on properties of wood adhesive with high starch content.International Journal of Adhesion and Adhesives, 72(1), 9297. Web.

The main claim of hedonism is based on the idea that pleasures and happiness are key goals in an individuals life, and this person is usually focused on pursuing happiness and avoiding pain. However, Robert Nozicks argument opposes this claim while offering that happiness cannot be the only state that is valuable for a person (Hindriks and Douven 278). In this context, the ideas of hedonism based on the importance of happiness are viewed by the researcher as wrong (Nozick 42-45). It is necessary to discuss why Nozick developed such vision of hedonism and focus on the things that are viewed by the researcher as intrinsically valuable in this particular context.

In his experiment involving the experience machine, the researcher proposed people to plug into this machine in order to have pleasurable experiences instead of facing their usual daily experiences. Nozick found that, in most cases, people refused to plug into the machine and, as a result, to reject experiences associated with their real life (42-43). The researcher concluded that hedonism is wrong in terms of stating that happiness should be viewed as the only valuable thing for people because, in the conducted experiment, people refused to experience pleasures associated with happiness in spite of proposed limitless opportunities (Hindriks and Douven 278-279). From this perspective, happiness cannot be directly and exclusively associated only with pleasures, and the pursuit of happiness is not the only intrinsically valuable thing for many people. Therefore, the reference of hedonism only to happiness and pleasures cannot be viewed as reasonable according to the researcher.

As a result of conducting the experiment, the author proposed his own vision of intrinsically valuable things in this context. Thus, Nozick suggested viewing the contact with reality while experiencing certain situations or feelings as the more intrinsically valuable aspect for people (44-45). The reason is that many people rejected to use the experience machine because they wanted to contact with reality, do certain things by themselves, and be certain personalities or live a certain way. The experience machine allowed people to feel many pleasures and become happy that way, but these pleasures were the result of the virtual reality (Nozick 44-45). According to the researcher, the contact with reality is extremely important for people in order to feel happy, and this aspect should be viewed as the intrinsic value because individuals feel happy or live happily not only as a result of pleasurable experiences but also as a result of acting or doing something important for them (Fletcher 356-358). Thus, living in reality is often regarded by persons as a more valuable thing than pleasures.

These ideas stated by the researcher are discussed as the counterargument to the philosophy of hedonism and its focus mainly on pleasures and associated happiness. Following the ideas proclaimed by Nozick, it is possible to state that the author does not agree with the opinion that pleasures and happiness are directly connected, and that both pleasures and happiness are intrinsically valuable for individuals. On the contrary, the researcher supported the vision that real-life experiences, not only pleasant ones, have more effects on people and their happiness associated with living, acting, and doing something. As a consequence, Nozicks argument based on the results of his experiment can be viewed as effective to oppose the key principles of hedonism.

Works Cited

Fletcher, Guy, editor. The Routledge Handbook of Philosophy of Well-Being. Routledge, 2015.

Hindriks, Frank, and Igor Douven. Nozicks Experience Machine: An Empirical Study. Philosophical Psychology, vol. 31, no. 2, 2018, pp. 278-298.

Nozick, Robert. Anarchy, State, and Utopia. Basic Books, 2013.