Salt in water, sugar in tea, sugar in water, drink powder/mix in water, sugar in coffee, etc... I hope I answered your question correctly!
The solid separates down to the molecular level - and they mix with the water molecules. We cannot see molecules with the naked eye !
Hey! The reason it seems to disappear is because of the refraction and absorption of light and colour. When light enters the colourless liquid, colour is obviously absorbed. The light waves refract ("bounce") off the glass test tube and leave the glass beaker (containing the colourless liquid). Because the liquid and solid are the same colour, it creates the illusion of the test tube disappearing.
Dissolving is where the solute (solid) fills the gaps in the solvent (liquid) particles, creating a solution (a mixture of solute and solvent).
liquid
Evaporation - the change of liquid or a solid into vapor, giving off moisture. Or to disappear, vanish or fade
solid
Solids do not evaporate, they Sublimate, i.e. they go directly from the solid state to a vapor. An example this process would be if you gently heat Iodine crystals, you will see purplish vapors begin to form ... it's sublimating.CAUTIONIf you try this, do it only in fume hood and with a very small sample of Iodine. The fumes are poisonous!
solid liquid
Liquid.
General classes of colloids are: gas in liquid, gas in solid, liquid in gas, liquid in liquid, liquid in solid, solid in gas, solid in liquid, solid in solid.
Solid
Pebbles are solid.