Refractometer Theory The speed of light in a vacuum is always the same, but when light moves

Refractometer Theory The speed of light in a vacuum is always the same, but when light moves through any other medium it travels more slowly since it is constantly being absorbed and reemitted by the atoms in the material. If you place a pencil in a cup of water, mollier diagram for steam the tip will appear bent. If you then put concentrated sugar water in a cup and try the same experiment, the tip of the pencil should appear even more bent. This is an example of the phenomenon of light refraction. . . . . __________________________________________________ ___ A refractometer measures the extent to which light is bent (i.e. refracted) when it moves from air into a sample and is typically used to determine mollier diagram for steam the index of refraction of a liquid sample, gases, and even transparent mollier diagram for steam or translucent solids such as gemstones. The density of a substance increases mollier diagram for steam (e.g. when sugar is dissolved in water) mollier diagram for steam , its refractive index rises proportionately The refractive index is a number, between 1.3000 and 1.7000 for most compounds, and is normally determined to five digit precision. Since the index of refraction depends on both the temperature of the sample and the wavelength of light used these are both indicated when reporting the refractive index. uses o The refractive index is determined as part of the characterization of liquid samples. Help identify or confirm the identity of a sample by comparing its refractive index to known values. Assess the purity of a sample by comparing its refractive index to the value for the pure substance. Determine the concentration of a solute in a solution by comparing the solution's refractive index to a standard curve in medicine it is used to measure the specific gratify of serum or urine. : ( ) ǡ . 1.3000 1.7000 . ( ) . . . . . . __________________________________________________ ___ Types of refractometers There are four main types of refractometers: 1. traditional handheld refractometers 2. digital handheld refractometers 3. laboratory or Abbe refractometers 4. and inline process refractometers. 5. the Rayleigh Refractometer used (typically) for measuring the refractive indices of gases. __________________________________________________ ___ principle 1. Refractometer is using a prism which has a much greater refractive index than the sample solution to be measured. Measurements are made possible using the refractive phenomena which arise at the surface between the prism and the sample solution. 2. In the case of a weak sample solution, the difference between the refractive index of the solution and that of the prism is great, therefore the angle of refraction is large (see A on the diagram below). 3. In the case of a strong sample solution, mollier diagram for steam the difference between the refractive index of the prism is smaller and therefore the angle of refraction is smaller (see B on the diagram below). mollier diagram for steam 1. . . 2. ɡ ( A ). 3. ( B ). __________________________________________________ ___
Step 1. Flip open the daylight plate on top of the refractometer. Place 2-3 drops of the specimen on the main prism. Close the daylight plate so the sample spreads across the entire surface of the prism without air bubbles mollier diagram for steam or dry spots.
1. . 2-3 . . Step 2. Hold the refractometer (daylight plate) in the direction of a light source and look i