Pour the sand into the jar containing the marbles. Note how the pores around the marbles are filled. For additional proof that open spaces still exist, add water to force out the air. The proportions of sand, silt, and clay determine the texture. In reference to texture we are concerned not with the kind of sand, silt, or clay, but with the particle sizes.
Sand is the largest particle and can be seen.
Sand feels gritty when rubbed between the forefinger and thumb. Silt is made up of smaller particules and has a floury feel. Clay is very fine and tends to be sticky. A good way to show these parts that make up soil is to use a small-diameter bottle or jar with a cover. Close the jar, shake vigorously for several minutes, then allow the soil to settle out.