This is a liquid.
This is a solid.
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.
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.
Solids: they have fixed shape and fixed volume. They cannot be compressed much. They cannot flow. They do not fill their container completely. They have high density. They are heavy. Liquids: they have fixed volume but not fixed shape they take the shape of their container. They cannot be compressed much. They can flow. They do not fill their container completely. They have moderate to high density. Gases: they do not have fixed shape and volume. They can be compressed easily. They can flow. They fill their container completely. They have very low density.
Very high density
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.
This is a solid.
Density
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.
Low density, no shape, high compressibility
Low density: gases Medium density: liquids High density: solids
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.
Matter can be classified according to its composition Solid: has a definite shape, mass & volume & are highly rigid. They cannot flow, have high density, are almost incompressible & have any no. of free surfaces. Liquid: has a definite mass & volume but no fixed shape & are less rigid. They can flow & take up the shape of the container in which it is stored. Gas: have a definite mass but have no fixed volume or shape & is not at all rigid. They can flow & take up the shape & volume of the container in which it is stored.
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.
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.