This document discusses a study that aims to investigate the effect of temperature and concentration on the refractive index of salt solutions. Specifically, it intends to determine the relationships between refractive index and salt concentration and temperature. It also aims to verify the validity of using a diffraction grating method and a locally-made instrument to measure the refractive index of solutions. The study involves preparing salt solutions of different concentrations and measuring their refractive indices at various temperatures using a diffraction grating setup and an Abbe refractometer for comparison.

1. THE EFFECT OF TEMPERATURE AND CONCENTRATION ON THE REFRACTIVE INDEX OF SALT SOLUTIONS AND ITS DETERMINATION USING DIFFRACTION GRATING METHOD ANDO, AILENE PACHEJO, ROMEL

2. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Rationale Theoretical Background Statement of the Problem Significance of the Study Research Methodology

5. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Snell’s Law of Refraction Theoretical Background n 1 is the refractive index of the first medium θ 1 is the measure of the angle of incidence n 2 is the refractive index of the second medium θ 2 is the measure of the angle of refraction n 1 sinθ 1 = n 2 sinθ 2

10. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Diffraction Grating Theoretical Background The diffraction pattern produced by the grating is described by m λ = d sin α m is the order number λ is a selected wavelength d is the spacing of the slits α is the angle of incidence of light

11. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Diffraction Grating Method Theoretical Background

12. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Related Studies Theoretical Background There is a linear increase in the index of refraction as solute concentration is increased. However, as temperature of the solution increased with constant solute concentration, index of refraction tends to decrease. The more molecules added into a solution (and the bigger the molecules are) the more of a chance the light has of hitting the molecules. This slows down the light as it goes through absorption and reemission, causing an increase in the index of refraction”. (Pham, 2008).

13. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Related Studies Theoretical Background Subedi, D.P., Adhikari et al., in 2006, studied the temperature and concentration dependence of refractive index of liquids using minimum angle deviation method. They found out the linear dependence of concentration on its indices of refraction. They were also able to determine the temperature coefficient of water the range 30°C- 70°C Grzegorz F. Wojewoda, (no date) used diffraction grating and polarization method in measuring the index of refraction of water. He realized that the refractive index does not deviate largely from the theoretical value. Frederick A. Osborn and Horace H. Lester (1912) also used the same method for determining index of refraction.

15. C The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Medical Professionals Through this research, doctors can identify salts precipitated from body fluids and measure relative amounts of sodium and potassium chloride which indicates whether or not a person has toxemia. Shipping industry Knowing the index of refraction of a body of water can indicate the salinity of water which can be one of the factors in the construction of a wharf. Biologists They will know the tonicity of a cell and the direction of the movement of its particles between it and its environment. Significance of the Study

16. C The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Science Community They are presented an alternative method of measuring the index of refraction of a solution. High School Laboratories High school students can perform experiment that measures the refractive index of a liquid at a lesser cost. Teachers and Students The teachers can demonstrate another way of measuring index of refraction for the benefit of high school students for this can equip them with much knowledge of the related concepts used in this study. Researchers This will enhance their analytical and critical thinking skills while performing this study. Significance of the Study

17. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Research Methodology Diffraction Grating Method Set-up Cutting tracing paper, sticking to one external wall of a vessel Stick diffraction grating to opposite wall Place laser next to diffraction grating

18. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Research Methodology Solution Preparation Masses of 200, 400, 600, 800, 1000 grams of salt are weighed Each sample will be put inside an empty and clean beakers. Each beaker will be filled with distilled water up to the 1000- mL mark. Mixing of each salt sample with water in beakers Computation of Concentration (percent by mass) Labeling of Beakers Exposure of the beakers to 3 different settings (hot, cold, room)

19. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Research Methodology Measuring index of refraction through diffraction grating method Room temperature to be constant (20 – 25 o C) Pouring of salt concentrations with temperature range of 75°C - 80°C into the vessel Switching on the laser, marking of the zeroth order fringe and the two first order fringe Changing height of laser and marking of fringes Repeat previous steps for salt solution with different temperature ranges Recording of date on table 1 Calculation of Refractive Index

20. The Effect Of Temperature And Concentration On The Refractive Index Of Salt Solutions And Its Determination Using Diffraction Grating Method Research Methodology Getting a sample for each salt concentration with temperature range of 75°C - 80°C Measure refractive index using improvised instrument and Abbe Refractometer Repeat previous steps for salt solution with different temperature ranges Measuring index of refraction through improvised instrument and Abbe Refractometer