I completed a version of this lab after Hurricane Katrina to demonstrate the major issues that flood water bring. You don't need any fancy equipment and it is a high-level inquiry. While the lab poses the question, "How do you separate oil from water?" the materials and methods students use is up to them. The lab is posted here in this Google Doc., "Marine Oil Spill." I'll admit, like any honest teacher will, that some of the labs we've done this year are better than others. My favorite so far is a lab I modified from Joel Beller's book, "25 Low-cost Biology Investigations." The lab in the book is called "Cleaning Up an Aquatic Oil Spill" and is found on page 43. I rewrote the lab and titled it, "Marine Oil Spill."
One of the first things you'll notice about my labs, is that I always include prelab questions. I have several reasons for this. For starters, my prelab questions often ask what they already know about the topic of the lab. I do this to address any misconceptions before we get started. [Although, sometimes the purpose of the lab itself is to help them sort through the misconception.] So, in this oil spill lab, the first prelab question is, "What do you know about how well water and oil mix? Use an example to explain your answer." My purpose here is to see if they know that oil and water don't mix. Common examples students think of, is salad dressing where the oil separates out of the mixture, or oil dripping from a car, and seeing it in a puddle. They don't mix!
Another main reason I have prelab questions is that I want students to read the lab before the scheduled lab time. Our time together is short, and if students have read the lab before coming, they are familar with what procedures they will be performing, and what equipment they will be using. Those of you out there that teach, know that this is easier said than done. Science literacy is not easy for students. The science vocabulary and strange apparatus often make student timid about what they are reading. In this oil spill lab, the second prelab question, "What is the difference between skimming and absorbing methods of oil removal?" helps students to read the lab and distinguish between the two major ways they will be trying to remove the oil from the water. The question, just by being asked, provides context for the lab's purpose.
Another purpose in having prelab questions is to force students to make a prediction regarding the outcome of the experiment. Ideally then, there is a postlab question that asks them whether or not their prediction was supported by the data they collected in the lab. In this oil spill lab, the third prelab question, "Make a prediction of what material will best help remove oil from water. Why do you think this material will work better than the others?" forces them to do several things. First, it requires them to look at the materials list, and see what items are available for removing the oil. Then they must think about what they know about oil, and pick the materials they think will do the best job, and explain why they picked that material over another. My last reason for having prelab questions is to address any safety issues. Whenever there are biological specimens, chemicals, heat, flames, etc...I use a prelab question to make sure they know how to handle the risk, and what to do if there is a problem.
The reason I like this lab so much is because the procedure is simple and the results vary. Meaning, even if 2 students both use a sponge to remove oil from the water, one may use it in a way that is successful while used by another, it may not remove the oil nearly as well. It brings up an opportunity to talk about the importance of scientists and engineers clearly describing HOW they perform their tasks. I also like the lab because the students can choose whatever materials they want, they can use materials in combinations, and then "grade" each materials' effectiveness.
This lab is conducive to a lot of discussion, not just teacher-student, but the more treasured, student-student, and student-teacher. Naturally, students share what they're finding. "Hey, using Rice Crispies made a huge mess..." or "....that worked much better, I wonder what would happen if..." I encourage students to think out loud. I want to hear how they are coming to their conclusions. I also want them listening to one another. [Sometimes I have to let them know this is not cheating, but collaborating!] I want them to provide suggestions to one another and challenge each other's methodology.
You'll notice that some of the boys chose to add food coloring to their "ocean water." That was their idea, hoping it would help them differentiate between the oil and the water. In the photo above dishwashing soap is being used in conjunction with corn chex. Several of the boys found this to be the best method for absorbing the oil, because it was easier to remove inside the cereal. Feel free to use this lab.
Whether you teach in public, private, or in your home, try this lab and let me know how it works for you and your students!