What is an Oil Boom? part 2

I got this from the Friends for Change website."How do they work? Because oil floats, the booms help round up and contain oil and keep it from expanding and contaminating beaches, islands, and wetlands. The boom has a weight, the floating tube, and a tall wall-like structure to help keep the oil contained. Unfortunately, during a storm, the oil can be pushed over the sides and escape. But experts are hoping that miles of boom will actually lessen the impact of the oil on our shores."