ANSWER: Correct Chapter 1 Question 7 Â­ True/False Part A A scientific theory is a tentative or untested explanation that is proposed to explain scientific observations. This preview has intentionally blurred sections.
Gravel /ËÉ¡rÃ¦vÉl/ is a loose aggregation of rock fragments. Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel (2 to 4 mm or 0.079 to 0.157 in) and pebble gravel (4 to 64 mm or 0.2 to 2.5 in).
Pebbles are next in size and are 4-64 mm in diameter (about 1/6-3 inches). The next sizes of sediments are very small, granules are 2-4 mm, sand 1/16-2mm, silt 1/256-1/16 mm, and the smallest sediment size is clay which is less than 1/256 of a millimeter in diameter. Sedimentary rocks are formed in three ways from these different sized sediments.