Impact of Sugar Concentration on the Refractive Index of Water

Impact of Sugar Concentration on the Refractive Index of Water
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 Table of Contents
Abstract 3
1.0 Introduction 4
1.1. Background 4
1.2 Purpose of the Study 5
1.3 Aims and Objectives 5
2.0 Literature Review 6
2.1 Theory of Evaluating the Refractive Index of Salt 9
3.0 Methods 12
3.1 Apparatus 12
3.3 Principle of Operation 14
3.3.1 Calculation 14
4.0 Results and discussion 16
4.1 Result of the Sugar Solution 16
4.2 Explaining the Reduction in the Refractive Index 18
4.3 Practicability of the Findings 18
4.4 Challenges 19
5.0 Conclusion and Recommendations 20
References 22
Abstract
Refractive index is a crucial optical property of any medium. It is plays a crucial role in different fields and applications of material science, playing a special role in fiber optics and the film technology. Similarly, the measurement of refractive index has been broadly applied in analytical chemistry in determining the concentration of different solutions. The experiment in this case was carried out to establish how the changes in a solution’s level of concentration impact its refractive index. A solution that was highly concentrated was prepared, with the sugar solution concentration being 60%. The refractive index was then measured before the concentration was lowered by 3% in the sugar solution. The refractive index was again measured with the new sugar concentration. The procedures were repeated continuously, reducing the level of concentration of sugar in the solution and then measuring the new refractive index. This was repeated several times until the required refractive index value was obtained when the sugar concentration in the solution was 3%. It was established that reducing the level of sugar concentration results in the refractive index reducing correspondingly. The same is true for other solutions; decrease in the concentration of the solute results in an equivalent decrease in the refractive index.
1.0 Introduction
1.1. Background 
I have taken a course in Physics for several years in college now. I have grown interest in different concepts about Physics, with refraction being one of them. I have always wondered how the refractive index is influenced by different concentrations and how sugar or salt could influence the refractive index. As such, I find this experiment highly applicable to my case as it solves personal questions. 
Refractive index is a crucial optical property of any medium. It is plays a crucial role in different fields and applications of material science, playing a special role in fiber optics and the film technology. Similarly, the measurement of refractive index has been broadly applied in analytical chemistry in determining the concentration of different solutions. Different researchers such as Tran, Sahoo, Wang, and Dang (2020) have provide literature on how measuring the refractive index of a certain liquid is used to map the concentration of the liquid. 
The Absolute Refractive Index of a particular medium is expressed in terms of the relationship between the speed of radiation in the medium and electromagnetic radiation in the free space. On the other hand, the Relative Refractive Index is expressed as the ratio of the speed of the light in a medium to that of another medium adjacent. Such ratios are important because they are used in evaluating such effects as how the refractive index of such liquids as water is influenced by the concentration of salt or sugar. It is also notable that refraction takes place with all forms of waves but it is more common with light waves (Tran, Sahoo, Wang, & Dang, 2020). Further, the refractive index of a particular medium differs depending on the frequency. The impact is referred to as dispersion and it is the reason that a prism divides white light such that the constituent spectral colors are clearly obtained. For a particular color, the refractive index of the medium is determined by the medium’s density, and this density is determined by the level of concentration of the solute. 
Since the concentration level of a solution determines the refractive index of the solution, the concentration of sugar determines the refractive index of water. Further, calculating the minimum angle by which light deviates when passed through a prism can help in calculating the refractive index within the medium that is used inside the prism. This principle is applied in this experiment report to show the effect of the level of sugar concentration on the refractive index of water. 
1.2 Purpose of the Study
This experiment was conducted with the purpose of establishing how change in the levels of a solution’s concentration affects the refractive index of the same solution. In this case, sugar solution was used and the refractive index was measured with reducing concentration levels. 
1.3 Aims and Objectives 
This experiment primarily aimed at showing that the refractive index of water is affected by concentration of sugar. The experimented was conducted to prove that the refractive index of a medium is influenced by the medium that makes up the medium. The primary objective of this study is to evaluate the degree to which the level of sugar concentration impacts the refractive index of water. This was achieved by conducting an experiment and using the findings to evaluate the refractive index of water when sugar was used, and how this varied when the sugar solution concentration was varied. 
2.0 Literature Review
The refractive index, n, is a fundamental characteristic of materials and many branches of chemistry and physics need the accurate value of the refractive index. This value also finds a broad application in many materials and industries in establishing the clarity of solid plastics and glasses, depending on their use. Measurement of the refractive index of a particular binary solution helps one in determining the concentration and constituents in the solution and the medium (Ylitervo, Franzén, & Taherzadeh, 2013). Therefore, measurement of the refractive index is one of the various applications of research and industrial applications and processes in determining the concentration of the solution. The process helps in establishing the refractive index, especially when the exact value is required depending on the exact application of a medium. 
Measuring the refractive index of a particular liquid solution is done using various approaches; previous literatures have documented such methods well. The availability of diverse methods of measuring refractive index is attributed to the differences in test objects, applications, as well as the expected level of accuracy of the measurement (Bahrami, Honarvar, Ansari, & Jamshidi, 2020). A separate collection of devices that are used in the measurement of refractive index in the case of liquids that are transparent contains systems which have been specifically designed to examine liquids contained in cuvettes that are made of quartz, glass, or other materials that are transparent. Over the past two decades or so, researchers have constructed several practical devices that are used for evaluating refractive index; the devices are based on the aforementioned principle using different cuvettes. 
As mentioned earlier, the refractive index of a medium varies based on various factors; pressure, temperature, concentration, and wavelength. Recent literature from studies conducted by Nideep, Ramya, Nampoori, and Kailasnath (2020) provided detailed research and analysis on how measuring the refractive index of different liquids is applied in the concentration mapping. Further, the temperature coefficient of the refractive index of a solution is also important as it is used in evaluating the coefficient of thermal expansion of the medium. The existing literature shows that there are various methods of measuring the impact of temperature concentration dependence levels on the refractive index of the sugar solution utilizing different methods. Researchers have developed various methods that are used in determining the contents of sugar in solutions and their impact on the refractive index in the case of water. Some of the techniques that have been developed in this regard include the following;
 Inter digital capacitor sensor; this method is used in evaluating the solutes of sugar in solution.
 Optical coherence tomography; this is used in determining the concentration of blood glucose among diabetic patients. 
 Refractometry, Density, statistical methods, and infrared spectroscopy; these techniques have also been developed and widely used in quantifying the concentration of sugar in fruit juices and soft drinks. 
These techniques are examples of instruments made in the industries and used for determining the level of sugar concentration in solution. Such types of instruments are expensive and also not easily accessible in many laboratories. As such, in this study and experiment, an equilateral hallow prism that was locally constructed and relatively inexpensive was used together with laser light sources that were very sensitive. These instruments were used to help in determining temperature, concentration, and wavelength that depends on the refractive index of the sugar solution as well as its constituents in various types of types of soft drink beverages through Snell’s Law (Wiederseiner, Andreini, Epely-Chauvin, & Ancey, 2011). The findings were also used to derive an empirical equation that defines the refractive index and wavelength of the sugar solution, through mapping Cauchy’s equation to the data collected from the experiment through the use of a non-linear curve with the minimum discrepancy. 
The method that was used in the experiment in measuring the sugar solution’s refractive index involves the use of LASER, which is an intense source of light and considered the most appropriate for this cause. For a specific color, the refractive index of the medium involved is determined by the density of that specific medium (Wiederseiner, Andreini, Epely-Chauvin, & Ancey, 2011). In the case of any solution, increase in the concentration level of the solution translates to increased density. One of the reasons for conducting this extended essay on refractive index is because it has become one of the most crucial optical phenomena of a medium. It is important in several fields of material science, especially in fiber optics and thin film technology as mentioned earlier. In addition, measuring refractive index has become widely used in the field of analytical chemist where it is sued in determining the concentration levels of solutions. Recent findings have also provided more in-depth discussion on how concentration mapping is achieved through measuring the refractive index of liquids. Researchers have also used the temperature coefficient of refractive index in calculating the coefficient of thermal expansion in specific liquids (Panta & Subedi, 2012). Literature also shows that there are various methods of measuring the impact of concentration on the refractive index in different liquids. This research reported a relatively effective and simple method, which can also be used in measuring the refractive index of different liquids at different levels of concentration. In this regard, M.T Teli used experimental data in developing the equation for evaluating how the volume of salt shrinks when it is dissolved in water, which was also considered in this experiment although sugar was used. The fact is that the principle is applicable to the case of sugar as it is to salt. 
An experiment conducted by C.V Raman in 1928 led to the discovery of another form of light scattering, although much weaker, where frequency change is recorded when the light is scattered (Panta & Subedi, 2012). It was also established that the frequency shift, Δν, was noted whenever part of the energy of the photon that was scattered was taken up by a molecule, thus exciting the molecule into vibration. Molecules mainly also exist in their ground state but the thermal agitation leads to some of the molecules to be excited. The process involved in this case basically involves the molecule being raised to a virtual excited state (non-existent) by the incoming photon. 
2.1 Theory of Evaluating the Refractive Index of Salt
The study of how radiated energy interacts with matter is referred to as spectroscopy. Spectroscopy is believed to have historically originated from the study of how visible light is dispersed depending on wavelength when it is passed through a prism. Researchers later expanded the concept greatly such that it comprised all interactions with radiant energy being considered a function of frequency or wavelength (Singh, Jaswal, Kumar, Prakash, & Rai, 2013).  The initial source of energy that was utilized in spectroscopic experiments was electromagnetic radiation. It is also notable that spectroscopy exists in different forms; UV spectroscopy, microwave spectroscopy, Gamma ray spectroscopy, IR spectroscopy, acoustic spectroscopy, MRI, and NMR, among others. Spectral measurement is done using spectrometers. A convenient and reliable formula for calculating the refractive index of a certain medium can be obtained by evaluating the minimum deviation in a case where a ray of light undergoes deviation as it passes in a prism. The deviation that the prism produces is determined by...