Refractive index

Refractive Index (Index of Refraction) is a value calculated from the ratio of the speed of Light in a Vacuum to that in a second medium of greater density. The refractive index variable is most commonly symbolized by the letter n or n' in descriptive text and mathematical equations.

Watch a beaker disappear when submerged. The vegetable oil and the borosilicate glass beaker have the same refractive index—a measure of light bending when passing from one medium into another. https://x.com/wonderofscience/status/1701969481856405744