the soil did not dissolve, on mix and disappear, into the water, because soil and water are composed of molecules of different types. There different molecules cannot chemically combine. the soil and water are what chemists call a "suspension" because the soil particles spread on become suspended, throughout the water and then later settle of the bottom of the jar, or come out of suspension. but water and salt do combine. the salt dissolves, or seems to disappear, in the water. its particles (crystals) do not fall to the bottom of the jar. this is an example of a solution, such as salt a "solute," and the liquid molecules, such as water, a "solvent