small
Lava will cool quickly compared to underground magma.
The decompression of air is an endothermic process. That means it absorbs heat. Air in a tire is under 35 to 40 psi of pressure. This pressure conpresses the gas inside the tire, so to speak. When you release the air, it rapidly expands and expanding gas cools the same as compressing gas warms up.+++Decompression is Exo-thermic! The pressure compresses the gas - err, well, yes. Compressing air means raising its pressure by reducing its volume; and if done rapidly also raises its temperature. The last bit is right: sudden expansion cools it.
crystal
It depends on what you mean. Are there quartz crystals on earth that are growing today? Yes. Is that quartz crystal in your rock collection still growing? No. Quartz crystals often form when water with super concentrated silica in it comes into contact with a surface (such as a very small crystal) onto which the silica can precipitate. Crystals also form when magma/lava cools and the different elements in the mixture differentiate into various minerals.
as air cools, the space it occupies becomes less. this result in an increas density
Not enough information. Some crystals will break if they cool rapidly, some crystals will not form correctly if the solution cools too quickly.
Due to lack of humidity and cloud cover, the desert cools rapidly after sunset.
Obsidian is neither an element nor a compound. It is a naturally occurring volcanic glass formed when lava cools rapidly without crystal growth.
crystal
Fine crystal grain.
Obsidian is an igneous rock that has a smooth glass-like texture. It is formed when lava cools rapidly without crystal formation, resulting in a glassy texture.
if lava cools slowly, it will have a lot of crystals. When it cools fast, there will be little to no crystals what s ever.
"Larger than if it cools quickly" is about all that's definitively possible to say.
coarse texture
Crystal size differs between extrusive and intrusive igneous rocks due to the rate of cooling. Intrusive igneous rocks, which form from magma that cools slowly beneath the Earth's surface, have larger crystals because the extended cooling period allows ions to arrange themselves into well-defined crystal structures. In contrast, extrusive igneous rocks form from lava that cools rapidly at the surface, resulting in smaller crystals or even a glassy texture due to insufficient time for crystal growth.
Fine
fine