Immersion oil

Immersion oil is a type of oil used in microscopy to increase the resolving power of a microscope. This is achieved by immersing both the microscope objective and the specimen in a transparent oil of high refractive index, thereby increasing the numerical aperture of the objective lens.

History

The use of immersion oil in microscopy dates back to the 19th century. The technique was first introduced by Ernst Abbe, a German physicist and optical scientist, who discovered that the resolution of a microscope could be significantly improved by immersing the objective lens in oil.

Types of Immersion Oil

There are two main types of immersion oil: Type A and Type B. Type A has a lower viscosity and is commonly used for routine microscopy, while Type B has a higher viscosity and is used for more specialized applications.

Use in Microscopy

In microscopy, immersion oil is used to increase the resolving power of the microscope. This is achieved by reducing the amount of light that is refracted as it passes through the specimen. By immersing the objective lens in oil, the light path between the specimen and the lens is made more direct, allowing more light to enter the lens and thereby increasing the resolution of the image.

Properties

Immersion oil has a number of properties that make it suitable for use in microscopy. These include a high refractive index, which is similar to that of glass, and a low volatility, which means it does not evaporate easily. It is also chemically inert, meaning it does not react with the specimen or the microscope.

See Also

• Microscopy
• Refractive index
• Ernst Abbe