Lab 11 -Saved to my Mac erences Mailings Review View Normal No Spacing Heading1
ID: 299650 • Letter: L
Question
Lab 11 -Saved to my Mac erences Mailings Review View Normal No Spacing Heading1 Heading 2 Tnle Sub dates, fixes, and improvements, choose Check for Updates. Post-Lab Questions 1. What is porosity and how is it determined? 2. What is specific yield? How is it determined? 3. What is permeability? How is it determined? 4. Given equal volumes of material, what affect do grain size, grain shape and sediment uniformity have on the porosity, permeability and specific yield of the sediment? Explairn your reasoning. 5. What is the difference between adhesion and cohesion? How do these properties affect the porosity, permeability and specific yield of soil? 6. Given equal volumes of material, which of the samples you used in this lab would make the best aquifer? Explain your reasoning.Explanation / Answer
Answer 1: Porosity is the space between the grains of a rock body. This inter-granular spaces of a rock body can determine a lot of characteristics of that rock. In sedimentary rocks, this inter-granular space is usually filled with a clastic material which binds the grain together, in igneous rocks, porosity can be due to the dissolved gas in the magma which escaped as the magma cooled down to form igneous rocks. The porosity of a rock can determine its density, it volume and also it susceptibility to fluids- the more compact a rock is, the less it will allow room for fluid to move through it.
Porosity can be calculated by dividing the space of the porous content of the rock body with the bulk volume of the rock body. Porosity is calculated gram per cubic centimetre. However, it is usually represented in percentage form and hence you will need to multiple the answer by 100.
Hence,
Porosity= [(Volume of the porous space) / (Total volume of the rock)] X 100
Answer 2:
To understand specific yield, let’s imagine an unconfined aquifer under the surface of the earth. This aquifer can transport water to the nearby rock bodies owing to the direction of pressure (if any), porosity of the surrounding rock and the direction of gravity. The volume of water that can be moved from a unit area of the aquifer (which in return will cause a unit area of decrease in the water table) is called the specific yield. In short, specific yield is the volume of water that we can extract for our use.
Specific yield will thereby be affected by the porosity of the rock and the moisture retention ability of the rock body.
Hence:
Specific Yield= Porosity – the specific fluid retention of the aquifer
Please repost the next questions separately since they need a detailed explanation as per the scenarios (unconfined aquifers/ confined aquifers)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.