Density - Getting Oil out of Water is Easy....(Robert Nairne)

Robert Nairne

Principles Illustrated

Most of my students have not been in tune with the dangers of oil spills in our oceans for animals and ecology. The most recent oil spill occurred on May 9, 2001 in the Galapagos Islands. The Galapagos Islands are located off the coast of Ecuador. The tanker, Jessica, tipped over pouring 240,000 gallons of oil into the ocean. This is a small experiment for the students to see how hard it is to get oil out of water.

Standards

7.7.A Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.

7.7.B Construct scale models, maps, and appropriately labeled diagrams to communicate scientific knowledge (e.g., motion of Earth’s plates and cell structure).

Prior knowledge & experience:

Knowledge of the concept that oil does float on water

Root question:

  • How hard is it to get oil out of water?

  • Is it possible to gather the oil without intaking any water as well?

  • What are some possible solutions to gather oil without much harm to the surrounding environment?

Methods for cleaning up include:

  • Bioremediation: use of microorganisms or biological agents to break down or remove oil

  • Bioremediation Accelerator: Oleophilic, hydrophobic chemical, containing no bacteria , which chemically and physically bonds to both soluble and insoluble hydrocarbons. The bioremedation accelerator acts as a herdin g agent in water and on the surface, floating molecules to the surface of the water, including solubles such as phenols and BTEX, forming gel-like agglomerations. Non-detectable levels of hydrocarbons can be obtained in produced water and manageable water columns. By overspraying sheen with bioremediation accelerator, sheen is eliminated within minutes. Whether applied on land or on water, the nutrient-rich emulsion, creates a bloom of local, indigenous, pre-existing, hydrocarbon-consuming bacteria. Those specific bacteria break down the hydrocarbons into water and carbon dioxide, with EPA tests showing 98% of alkanes biodegraded in 28 days; and aromatics being biodegraded 200 times faster than in nature

  • Controlled burning can effectively reduce the amount of oil in water, if done properly.wind, and can cause air pollution. But it can only be done in low

  • Dispersants act as detergents, clustering around oil globules and allowing them to be carried away in the water.This improves the surface aesthetically, and mobilizes the oil. Smaller oil droplets, scattered by currents, may cause less harm and may degrade more easily. But the dispersed oil droplets infiltrate into deeper water and can lethally contaminate coral. Recent research indicates that some dispersants are toxic to corals.

  • Watch and wait: in some cases, nautural attentuation of oil may be most appropriate, due to the invasive nature of facilitated methods of remediation, particularly in ecologically sensitive areas.

  • Dredging: for oils dispersed with detergents and other oils denser than water.

  • Skimming: Requires calm waters

Common Misconceptions:

  • Getting oil out of water is easy

  • Oil does not effect the surrounding areas of the spill

Photographs and Movies