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).
The depth you will need for the gravel or aggregates will depend on what size you use and what it is used for. Generally you would lay a 10mm aggregate at 3-4cm (approx 1.5) deep, but on a drive you would go to 5cm (approx 2). A 20mm aggregate would need to be 4-5cm deep (approx 2) and a little deeper on drives.