You are asking for comparatives. Each state can be any when compared to another state except the extremes. Liquid or gas either lower or higher depending on what you compare it to.
This is a solid.
This is a liquid.
It's not necessary. If a compound has high optical density, it means that it absorbs more light at the given wavelength than some reference compound. There is no simple relation between density of matter and optical density. Even more I am pretty sure you can find a lot of compounds with lower densities (of matter) but having high optical density.
Very high density
High density plasma of high density polyethylene.
Low density: gases Medium density: liquids High density: solids
This is a solid.
Quite low density: 0.968 g·cm−3
Density
This is a liquid.
It's not necessary. If a compound has high optical density, it means that it absorbs more light at the given wavelength than some reference compound. There is no simple relation between density of matter and optical density. Even more I am pretty sure you can find a lot of compounds with lower densities (of matter) but having high optical density.
Yes, the population density is quite high.
High density is a characteristic of a Gas. When something has a high density it means there is a lot of a certain gas, in one area.
high density have more matter per unit of volume (a box with a lot of circles) low has fewer matter per unit volume (a box with less circles)
You can use a centrifuge machine which spins small test tubes at very high speeds causing the lower density matter to rise and the higher density matter to sink. This leaves you with a density gradient of the different types of matter in your mixture.
void is anti matter in high density mass which due to high gravitational force may cross the threshold of the speed 3 x 108 km/sec to form matter.
Many people know about the many states that all matter on earth can take. From solid to liquid and from gas to plasma, all of them have different properties which are what distinguishes one from the other. The gas state, for example is a state in which the matter has indefinite shape and volume, it also has a very low density and a high compressibility.