*Rate: how much oil was flowing into the Gulf each day?*

Rate = total volume of oil leaked/ # of days leaking

**Exercise:** calculate the oil flow rate April 27 or April 29, about a week after the explosion.

*Compare your results with SkyTruth’s*

*April 25* =^{ } 2,103 km^{2}

SkyTruth didn’t calculate a volume or flow rate for this date. If their area calculation is different from yours, calculate for them what the volume and flow rate was on this day, based on their interpretation of the images.

*April 27
*

**Area** = 5,783 km^{2}

**Volume** = at 1 µm thick = **5,783 cubic meters (m ^{3}) of oil** or

**36,374 barrels**

**Rate** =36,374 barrels/7 days =** 5,196 barrels/day**

SkyTruth concluded that, at a minimum, more than 5,000 barrels were spilling to the Gulf each day by April 27. They didn’t calculate on April 29. If you calculated the size of the spill on April 29, how much larger did it get in just 2 days?

But if 3% of the area was 100 µm thick, as the BP executive said, and the remainder (5,609.5 km2) was 1 µm thick then the volume is: 22,960 m^{3} of oil; 144,414 barrels.

* May 1: *6,734 km

^{2}

Combining satellite imagery with aerial overflights by the Coast Guard, SkyTruth estimated a flow rate of 26,500 barrels/day.