Friday, January 8, 2010
Glycerin is a neutral, sweet-tasting, colorless, thick liquid which freezes to a gummy paste and has a high boiling point. Glycerin can be dissolved into water or alcohol, but not oils. On the other hand, many things will dissolve into glycerin easier than they do into water or alcohol. So it is a good solvent.
Glycerin is also highly "hygroscopic" which means that it absorbs water from the air. Example: if you left a bottle of pure glycerin exposed to air in your kitchen, it would take moisture from the air and eventually, it would become 80 per glycerin and 20 percent water.
Because of this hygroscopic quality, pure, 100 percent glycerin placed on the tongue may cause a blister, since it is dehydrating.
Why does the test tube disappear?
Glycerin has essentially the same refractive index as glass, so any light passing through the two is bent equally. Since both are transparent it's not possible for your eye to distinguish the boundary by a change in the angle of refraction, and the glass seems to vanish.
Index of Refraction
The index of refraction is defined as the speed of light in vacuum divided by the speed of light in the medium.
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| Material | Index | |
| Vacuum | ||
| Air at STP | ||
| Ice | ||
| Water at 20 C | ||
| Acetone | ||
| Ethyl alcohol | ||
| Sugar solution(30%) | ||
| Fluorite | ||
| Fused quartz | ||
| Glycerine | ||
| Sugar solution (80%) | ||
| Typical crown glass | ||
| Crown glasses | ||
| Spectacle crown, C-1 | ||
| Sodium chloride | ||
| Polystyrene | ||
| Carbon disulfide | ||
| Flint glasses | ||
| Heavy flint glass | ||
| Extra dense flint, EDF-3 | ||
| Methylene iodide | ||
| Sapphire | ||
| Rare earth flint | ||
| Lanthanum flint | ||
| Arsenic trisulfide glass | ||
| Diamond |
+ [ written by SEOWHWEE ] + 11:35 PM