Debates have been raging over whether using chemical dispersants to clean up the Gulf oil spill was a good idea. Some scientists and government officials insist using the dispersants is better than using nothing, while others argue the chemicals do more harm than good to the Gulf ecosystem. David Valentine, a geochemist at the University of California-Santa Barbara, is studying how the chemical dispersant Corexit might interact with the natural bacteria that usually break down oil in the Gulf.

Using three vials to mix oil with Corexit, plain water and naturally occurring bacteria, Valentine demonstrates how the bacteria can actually disperse the oil in the water just as well as the Corexit. Valentine is wondering whether adding Corexit somehow impacts the natural bacteria's ability to disperse oil on its own.

Valentine is also interested in finding out the answer to a question that's been on everyone's mind: How much oil has really leaked into the Gulf since the Deepwater Horizon rig exploded on April 20? Valentine proposes using measurements of the gas methane to find out and explains his theory in this video.

"The National Science Foundation has been funding us to find out how the addition of the Corexit is impacting the ability of the bacteria to consume the oil." - David Valentine, geochemist at the University of California-Santa Barbara

"If action is taken in the next week or two, it might be possible to go out, quantify the methane and then determine how much oil has spilled over the course of this entire event from that measurement." - David Valentine, geochemist at the University of California-Santa Barbara

1. What does it mean to "disperse" something?

2. What techniques have cleanup workers been using to get rid of the oil that has spilled into the Gulf of Mexico?

3. What do humans use oil for?

1. What do you think would be the benefits of using naturally occurring bacteria to break down oil instead of using chemicals?

2. Based on what you've learned about the methods that are out there to clean up oil, how would you clean up the Gulf oil spill? Why?

3. Why are chemicals sometimes dangerous to living things? What kinds of chemicals can hurt humans?