Density & Miscibility
Density and miscibility properties explain the layering and non-mixing seen in liquid "density columns." The unique nature of water's hydrogen bonds is part of the story.Copyright (top) NASA, (bottom) 2007 Michael Mañas, Wikimedia Commons http://microgravity.grc.nasa.gov/wing_images.html http://commons.wikimedia.org/wiki/File:3D_model_hydrogen_bonds_in_water.jpg
After students conduct the two associated activities, Density Column Lab - Parts 1 and 2, present this lesson to provide them with an understanding of why the density column's oil, water and syrup layers do not mix and how the concepts of density and miscibility relate to water chemistry and remediation. Topics covered include miscibility, immiscibility, hydrogen bonds, hydrophobic and hydrophilic. Through the density column lab activities, students see liquids and solids of different densities interact without an understanding of why the resulting layers do not mix. This lesson gives students insight on some of the most fundamental chemical properties of water and how it interacts with different molecules.
For any source of contaminated water, environmental engineers must understand the physical properties and, especially, the chemical properties of contaminants so as to better understand how they interact with water molecules. An understanding of how liquids interact, explained by the science of molecular bonding, is pivotal to environmental engineering in terms of contaminated water remediation and water treatment to provide safe drinking water.
After this lesson, students should be able to:
- Define the properties of miscibility and hydrophobicity and describe their relationships with water molecules.
- Explain why certain liquids do not mix, based on concepts of miscibility, hydrogen bonds and hydrophobicity.
- Relate the physical properties of water and hydrophobic compounds to groundwater contamination and remediation.