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Understanding How Oil Reacts on Water: A Simple Experiment

Have you ever seen a rainwater puddle on a street and wondered why it seemed to have a rainbow floating on top? That rainbow effect is caused when oil on the street floats to the top of the puddle.

Understanding how oil and water react together is an essential part of the science of cleaning up oil spills. One of the goals of NOAA's Office of Response and Restoration (OR&R) is to share our scientific expertise and experience. Fostering scientific understanding of oil spills helps everyone prevent and prepare for marine pollution.

Here is a simple experiment for elementary-aged children that can be done with common household items to understand how oil reacts in water.

OR&R has more experiments and activities for elementary school students and life-long learners on our education page .

Oil floating on water creating a sheen with multiple colors.
Rainbow sheen, such as the one shown here from a different incident in the Gulf of Mexico, has been spotted near the leaking natural gas well off the Louisiana coast. (NOAA)