How does a refractometer work?

[parthenope]

Could anyone explain to me how Abbe and Pulfrich refractometers work?
They are such specific types of instrument I haven't been able to find any information detailed enough on the internet or in books.
Does anyone know details on how they work, differences between them or a website or book which explains about them?
Contact details of an organisation/ person who might know would also be greatly appreciated!
Any information would be useful - thank you in advance.

 

[Andy Resnick]

Typically they work by total internal reflection- when the critical angle is measured, the index of refraction can be calculated.

 

[astrokreng]

A refractometer is a scientific instrument used to measure the refractive index of a substance. The refractive index is a measure of how much a substance bends light as it passes through it. This property is related to the composition and concentration of the substance.

Abbe and Pulfrich refractometers work in a similar way, but they have different designs and are used for different purposes. The Abbe refractometer is used for measuring the refractive index of liquid samples, while the Pulfrich refractometer is used for measuring the refractive index of solid samples.

In general, a refractometer works by shining a beam of light through the substance and measuring how much the light is bent. The instrument has a prism or a series of prisms that refract the light as it passes through the sample. The angle at which the light is bent is then measured and compared to a standard scale to determine the refractive index.

The Abbe refractometer uses a prism and a monochromatic light source, typically a sodium lamp, to measure the refractive index. The sample is placed on the prism and the light is refracted through it. The angle of refraction is then measured using a telescope and compared to a standard scale to determine the refractive index.

The Pulfrich refractometer, on the other hand, uses a series of prisms and a white light source to measure the refractive index. The sample is placed on a rotating prism and the light is refracted through it. The angle of refraction is measured using a telescope and compared to a standard scale to determine the refractive index.

There are some differences between the two instruments, such as the type of light source and the method of measurement, but they both work on the same basic principle of measuring the angle of refraction to determine the refractive index.

For more information on these specific types of refractometers, you may want to consult a scientific instrument manufacturer or a laboratory equipment supplier. They may have more detailed information on the design and operation of these instruments. Additionally, online resources such as scientific journals or textbooks may also provide more in-depth explanations of how Abbe and Pulfrich refractometers work.