In theory, if two materials have exactly the same refractive index, the light passes through without any (or minimal) scattering or refraction. The light travels straight because it cannot detect any difference in the two materials, hence the speed of the travelling light does not change (bend).

The refractive index of essential oils can easily be measured with an Abbemat refractometer. It can thus provide insight as to their quality.

You see a glass object because it both reflects and refracts light. When light traveling through air encounters a glass surface at an angle, some of the light reflects. Wesson vegetable oil has nearly the same index of refraction (n) as Pyrex glass (n = 1.474).

The flotation and immersion methods are best used to determine a glass fragment’s density and refractive index, respectively. The latter involves immersing a glass particle in a liquid medium whose refractive index is verified unit it is equal to that of glass particle.

In this “magical” science demo, the oil and the small glass beaker have the same index of refraction. That means that light doesn’t change speed or direction when it passes from the oil to the beaker and back. Since the small beaker does not bend the light, we can’t see it!

When light hits a glass object, some of the light bounces (or reflects) off the glass. Therefore, as light travels through the oil and into the glass eyedropper, very little of it is reflected or refracted. As a result, we see only the “ghost” of the eyedropper in the oil.

This occurs because both Pyrex glass and cooking oil have the same index of refraction, meaning that they both allow light to pass through them at the same speed, causing the glass to disappear. Science!

Ordinary glass will not disappear in vegetable oil because ordinary glass has a different refractive index (n ≈ 1.5 to 1.7). When light enters a clear medium like glass or water, it slows down. In a vacuum, light travels at 300,000,000 metres per second*. In water, it slows down to 225,000,000 metres per second.

Glass and water are thicker and heavier than air. What happens is that light slows down when it passes from the less dense air into the denser glass or water. This slowing down of the ray of light also causes the ray of light to change direction. It is the change in the speed of the light that causes refraction.

Whenever light encounters an abrupt change in refractive index (how much a ray of light bends as it crosses from one material to another, such as between air and glass), a portion of the light is reflected. Reflections are reduced so much that the glass essentially becomes invisible.

This is because light travels through glass and glycerin at the same speed, so your eyes don’t see a boundary where the bottle is, rendering it invisible. Glycerin is a liquid that is sold at most drugstores as a skin softener and protectant.

about 1.45

3 Answers. The index of refraction of the lens will remain the same (the medium remains the same, whether in a vacuum, in air, immersed in water, etc.), but the focal length will increase.

For a solution of sugar, the refractive index can be used to determine the sugar content (Brix degree). It can be used also in determination of drug concentration in pharmaceutical industry. It is used to calculate the focusing power of lenses, and the dispersive power of prisms.

When any lens or glass slab is immersed in a liquid whose refractive index is equal to that of lens, refractive index of lens will be equal to 1 relative to that liquid. The focal length of the lens in this case, will tend to infinity.