whats the difference between glass and crystal.?
151094
Glass is a manmade material that is made of melted sand that has been shaped and molded. Crystals are naturally occouring mineral formations caused by extreme pressure and heat from rock layers when the crystals are formed. They are similar (in that they can both be caused by heat), but one is natural and one is manmade. Crystals also have much more magical energy.
579813
The glass of water is acting as a lens to refract the light coming from the clock.  Refraction is the bending of light rays as they pass through a medium such as water or glass.  Various materials refract light differently.  This fact is the basis for some analytical instruments such as the refractometer.  Also, light of different wavelengths is refracted differently within the same medium.  This, too, is a basis for the above mentioned analytical instruments.  But, the simple one word answer to your question is "refraction".
149062
The question is not clear.  Are you asking what a crystal is?  Are you asking what the different crystal structures are?  Are you asking for the characteristics of crystals in general?
1152488
boundaries between crystal grains are less well defined than the actual crystals, and have a different refractory index or optical density.\n\nIn anisotropic crystals, the refractory index or the surface structure of a transparent cut also depends on the orientation of the crystal.
1139890
depends on the type of glass and also the conditions of the place you are working in
346695
An alum solution with water makes a very nice crystal and is hydrated.  Check out this website with how to grow crystals: \n\nhttp://chemistry.about.com/cs/howtos/ht/alumcrystal.htm\n\nIn short, A hydrated crystal is a crystal that contains water as part of its chemical formula and structure. It may or may not absorb water vapor from the atmosphere. A crystal that is hygroscopic is one that absorbs water\nvapor from the atmosphere. CaCl2 and P2O5 are examples.
60088
Glass is made up of mostly silica sand.  In order for the sand to become glass, it must be heated up to a super-hot tempature of 1,982°C/3.600°F.\nUsually white sand is preferred when making glass, because of lower concentrations of iron, which turns the glass a greenish color.\nSometimes lead is added to sand to make a softer type of glass with exceptional clearity.  Max. lead content can only be 33%.  It is more complex to work with, but easier to cut.\n\nTwo natural glasses that occur are: obsidian, a natural by-product of volcanic eruptions; also, fulgrites, which are formed when lightning strikes sand or rocks, super-heating then cooling, forming glass.
357158
Glass or perspex(plastic).Each have their advantages and disadvantages
508036
Glasses and contacts operate on the same basic principles, but contacts have to accomplish the same thing in a much smaller space (for obvious reasons).  Contacts are often made out of more bendable materials, for comfort.  Since they are closer to the eye than glasses, they are also more curved.  I suspect that the materials used in contacts may have a higher index of refraction than glass, since they're not as thick, but I don't know if that's true or not - just conjecture on my part.
293478
both will have a miniscus and this is due to the adhesive property of water. the cohesive property keeps the water molecules togherter but the adhesive props allow for movement as in a cappilary tube. the gLass is clearer than the plastic so im thinking glass
633202
It is made by heating sand.\nGo to wikipedia.org\nThen type in just glass in the search engine.\nhttp://en.wikipedia.org/wiki/Glass
259893
It cant be just any piece of glass, it has to be a prism. The light comes out in the form of a rainbow because the prism separates the light into it's visible colors.
244328
no a diamond is a type of rock.\n\na crystal is a type of glass.\n\nsimilar, but not quite the same.
912103
Emeralds are Beryl, which has a hardness of 7.5 to 8 and can certainly scratch glass. Glass is silica, with a hardness of 6 to 7.\nDiamond, the hardest of all substances, gets the big 10. \nBeryl has been found in about every color of the rainbow, but green is most common.
593379
what is the difference between the two
646733
glass has the property to transmit light from one side to the other side of it. other objects stop the light..or atleast do not pass the light fully.. thats why glass is tranparent to the other side
506028
glassy - cools very fast; extrusive igneous rocks; no crystals; includes obsidian & pumice\nfine-grained - cools quickly but not as fast as above; crystals don't have time to grow large; crystals are generally all the same size\ncoarse-grained - larger size crystals; usually intrusive igneous rocks; crystals are usually uniform\nporphyritic - has two different & distinct crystal sizes that resembles a "chocolate chip cookie" as I tell my students; the larger grains are fewer than the smaller ones