Lesson: Oil SpillContributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Educational Standards :
Pre-Req Knowledge (Return to Contents)
Before this lesson students should understand the concept of density.
Learning Objectives (Return to Contents)
After this lesson, students should be able to:
Introduction/Motivation (Return to Contents)
The Exxon Valdez oil spill was one of the largest oil spills in history. It took place in Alaska in March 1989, when an oil tanker ran aground, causing 10.8 million gallons of crude oil to spill into Prince William Sound. While this was indeed a huge spill, it was actually only a small fraction of what the United States uses in oil in any one day. The United States uses about 700 million gallons of oil every day. That is a lot of oil — enough to completely fill 9 school gymnasiums!
How do we use oil? (Answer: To operate cars and other methods of transportation; to run our electrical power plants; for lubrication, for things such as bicycles and doors; to make paint and varnishes; and to run machinery, among other things.) Oil spills often are caused by human mistakes. Sometimes, they happen when natural weather disasters occur, such as when a hurricane destroys oil mining equipment or oil tankers; other times, they occur when large industry machinery breaks down. Unfortunately, spills are sometimes caused by deliberate acts, such as citizens dumping oil illegally or even during times of conflict (war) as a means of sabotage.
There are several characteristics of oil that make oil spills very dangerous and difficult to clean up. One important quality of oil is it is less dense then water, which means it will float in water. In order to motivate students to observe and estimate densities of several different liquids, have four students volunteer to stand in the front of the classroom and pour equal quantities of the following liquids into one graduated cylinder: water with food coloring, Karo® corn syrup, light vegetable oil, and rubbing alcohol. Have the students rate the liquids from most dense to least dense. (Answer: In order from bottom (most dense) to top (least dense) of the cylinder: Karo® syrup water vegetable oil rubbing alcohol; remember: the oil floats on water.)
When an oil spill occurs, environmental engineers work to help clean it up. Have you ever noticed a rainbow puddle on the street or parking lot after a rain? That rainbow sheen that you see on top of the water is actually oil from cars that has leaked onto the ground. Environmental engineers are responsible for assessing what type of cleanup method is best for different situations. They examine the weather patterns of the area, the type of oil that was spilled, and what living creatures are, or will be, affected by the spill. Is there a community nearby? Are there a lot of plants or animals in the area? Some of the methods engineers use are dispersants (chemicals used to break down the oil); booms and skimmers (used to contain the oil and avoid spreading); absorbents and vacuum cleaners; burning the oil; and biodegradation (the use of microorganisms that digest oil). Today, we are going to act as environmental engineers and learn how these different techniques can be used to clean up oil spills.
Lesson Background & Concepts for Teachers (Return to Contents)
Exxon Valdez: What happened?
At 9:12 p.m. on March 23, 1989, the Exxon Valdez departed from Prince William Sound, Alaska. There were several people in charge of the ship. The pilot William Murphy, the captain Joe Hazelwood and the helmsmen Harry Claar all were challenged to steer the 986 ft. ship — carrying 53,094,510 gallons of oil — through the Valdez Narrows. Navigating through the Valdez Narrows is exceptionally challenging because of the Bligh Reef, which makes the narrows just 500 ft. wide. That night the Exxon Valdez came across an iceberg, so Captain Hazelwood ordered the helmsmen to turn the ship out of the shipping lanes and around the iceberg. Later that evening the wheelhouse was turned over to Third Mate Gregory Cousins and Helmsman Robert Kagan. They were given specific instructions to turn the ship back into the shipping lanes at a certain point to avoid the reef. However, due to reasons unknown at this time, the helmsmen did not steer the vessel back to the channel, and at 12:04 a.m. on March 24, the Exxon Valdez ran aground on Bligh Reef, spilling10.8 million gallons into Price William Sound.
It is unclear who was at fault. The captain was seen drinking at a local bar and had alcohol in his blood several hours after the accident, but he was asleep when the boat ran aground. Was it his fault? A jury in Alaska ultimately found him not quality of running the ship aground. Hazelwood was however, charged with negligent discharge of oil and fined $50,000 as well as 1000 hours of community service.
Today, Exxon Shipping Company is operating under the new name Sea River Shipping Company. The Exxon Valdez, now the Sea River Mediterranean, was repaired but is prohibited from entering Prince William sound.
Effects of the Spill
It is estimated that 10.8 million gallons of oil leaked from the Exxon Valdez — enough oil to fill 125 Olympic sized swimming pools. The spill is the largest spill ever in the United States. Oil covered about 1,300 miles of shoreline, with 200 miles heavily covered and 1,100 lightly covered. The impact of an oil spill of this magnitude is tremendous. Exxon has paid $2.1 billion to clean up the spill, but the effects are still being felt today. The ecological impacts are impossible to know because the effects of the spill will still be felt for many years to come. It is estimated, however, that the oil spill killed 250,000 seabirds, 2,800 sea otters, 300 harbor seals, 250 bald eagles 22 killer whales and billions of salmon and herring eggs. Today 10 years later, only two of the 23 species that were injured by the spill have recovered.
During clean up of the Exxon Valdez oil spill, environmental engineers worked to develop methods that could prove helpful in such a large disaster. They tried traditional mechanical methods: backhoes to sift through sand covered with oil-soaked soil and high pressure hot and cold water treatments to wash the oil off the shore to be scooped up by skimmers or adsorbed by adsorbent material. Additionally, they used the uncommon method of bioremediation: adding fertilizer to the beaches to promote the growth of bacteria that can degrade the oil. During the Exxon Valdez oil spill clean up, environmental engineers learned a lot and optimized many processes. The use of bioremediation, for example, was not commonly used before Exxon Valdez oil spill, and now it is used for many different applications. Conversely, the use of hot water treatment was very common before the Exxon Valdez oil spill. However, during the Valdez clean up, they found that hot water treatment actually did more damage then good, because it harmed many of the small organisms living in the water.
More information on the oil spill can be found at the Exxon Valdez Oil Spill Trustee Council website (search for Council website through any Internet search engine).
Vocabulary/Definitions (Return to Contents)
Associated Activities (Return to Contents)
Lesson Closure (Return to Contents)
Today we looked at the cleanup of oil spills — in particular, the 1989 Exxon Valdez oil spill. We remembered that oil is less dense than water and therefore floats on the water, causing harm to the organisms that need that water source to live. Environmental engineers are often employed to help cleanup oil spills and return an environment's ability to provide food, water, space and essential nutrients back to its original state. We citizens can help prevent some oil-related problems by using less oil in our daily lives, whenever possible.
Discuss with students the effectiveness of cleaning up an oil spill. After trying to contain, clean, dissolve or remove the oil spill with the various utensils and "chemicals," did the students ever reach a pristine environment? (Answer: probably not) Is it better to use more than one technology to clean up the oil spill? (Answer: usually, yes) What are some ideas they have for helping cleanup oil spills? (Answers will vary.)
If time permits, have students compare methods they used to clean up their model oil spills with the methods currently used to clean up actual oil spills. The following comparisons can be made: dispersants (chemicals used to break down the oil) to soap; booms and skimmers (used to contain the oil and avoid spreading) to pieces of thread and cotton balls; absorbents and vacuum cleaners to paper towels and pipettes; and burning the oil to using matches.
Assessment (Return to Contents)
Brainstorming: As a class, have the students engage in open discussion. Remind students that in brainstorming, no idea or suggestion is "silly." All ideas should be respectfully heard. Take an uncritical position, encourage wild ideas and discourage criticism of ideas. Have them raise their hands to respond. Write their ideas on the board.
Discussion Question: Solicit, integrate and summarize student responses.
Question/Answer: Ask students the following questions to determine their understanding of the Exxon Valdez oil spill.
Problem Solving: Ask students to calculate how many classrooms the Exxon Valdez oil spill would fill up if each classroom is 20' x 20' x 10' (height). (Answer: There were 10.8 million gallons of oil spilled in the Exxon Valdez oil spill. 7.4805 gallons = 1 cubic foot. 10.8 million gallons would equal about 1,443,753 cubic feet or about 361 classrooms that were each 20' x 20' x 10' (height) (4000 cubic feet volume).
Lesson Summary Assessment
Persuasion Papers/Oral Defense: Engineers often have to explain their point of view to companies, communities or conference attendees. Have students defend the position of an environmental engineer with regard to pollution in a one-page persuasive piece. They should be able to explain the jobs environmental engineers perform, the sources of pollution and why pollution is bad for the environment. If time, have them explain their position orally.
Community Debate: Have students write/perform a short play or debate about the lesson topic. The setting is a town meeting about a relevant issue. The people present are: an environmental engineer, an oil company owner, captain of an oil tanker, a local politician, and various citizens. The scenario is a large oil spill (from an oil tanker) in the community marina or local body of water.
Lesson Extension Activities (Return to Contents)
This lesson provides an opportunity to introduce or review a variety of concepts including solubility, density and biological effects of pollution. Some possible questions for discussion may include: Why did the oil and water not mix? How can we keep the oil from washing onto beaches? What was produced when oil burned? How could the air be polluted? What would happen if the oil had been denser than water? What are some dangers of a large oil spill, such as the Exxon Valdez spill?
Ask the students if they know how an oil spill in a neighboring body of water will impact the economy of a country. Have the students research a few of the most recent oil spills in the world and their resulting economic effects.
Students could be challenged to estimate the relative and exact densities of each liquid used in the demonstration during the Introduction/Motivation section.
References (Return to Contents)
Exxon Valdez Oil Spill Trustee Council (organization website available on the Internet).
Office of Response and Restoration, National Ocean Service, National Oceanic and Atmospheric Administration (organization website available on the Internet).
ContributorsSharon D. Perez-Suarez, Melissa Straten, Malinda Schaefer Zarske, Janet Yowell
Copyright© 2005 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.