Published: Jun 02, 2010 3:31 AM EDT
Updated: Jun 02, 2010 12:31 AM EDT

CAPE CORAL, Fla. - Concern is growing about when the oil could hit the Florida coast.  While there are still no official reports of oil on Florida's shores, plenty of people are still on the lookout for any signs of its arrival.

"It floats in amongst the grass, it floats by, doesn't look like anything special until you pick up and touch it," said Phil Luster of Cape Coral, who spotted something strange Tuesday while boating in the Gulf of Mexico off Sanibel.

"It's oil.  To me, it's oil.  There's globs of it."

If it really is oil, and where it came from, isn't clear, and would require testing. 

With so many boats around, scientists say small amounts of oil appear in the gulf all time; the spill in the gulf, while large, moves slowly.

NOAA, the National Oceanic and Atmospheric Administration, posts experiments on its website that can help people understand what happens when oil interacts with water:

Oil floats on top of the water because there of a density difference between the two materials; that's why you get the oil sheen on top of the gulf.  But over time and over distance, things change with the oil, it interacts with things like wind and waves and mixes up, like when you're making a salad dressing.  It emulsifies, something NOAA calls a "mousse," making the oil harder to clean up.

NOAA says the characteristics of the oil then continue to change; it becomes "weathered," forming dark, gooey tar balls.  That, not a sheen, is what environmental officials expect would show up in this part of Florida.

If you do spot possible oil, the Department of Environmental Protection wants you to call 877-2-SAVE-F-L.  They'll send out trained teams to investigate what it is, and where it came from.

What to know about reporting oil in Florida (PDF file from DEP)

What is a tar ball? (PDF file from DEP)

Experiments for students and teachers to understand the oil spill (from NOAA)