On Jan. 15, 1919, a giant storage tank collapsed and released more than 2 million gallons of molasses, sending a wave of goo down the streets of Boston.
Fatal Flood Of Molasses
The wave from the sticky tsunami reached about 25 feet tall and flowed at more than 50 feet per second. The molasses, dark and viscous liquid that is generally made from sugarcane and is commonly used in cookies, quickly engulfed the Commercial Street area of Boston. The incident killed 21 people, injured 150 and flattened buildings.
Now, nearly 100 years after the incident, scientists have finally figured out how the flood of viscous sweetener became so deadly with horses dying just like flies stuck on sticky flypaper.
Scientists revealed that cool temperatures may be to blame why the flood of molasses was so fatal. The cold temperature may have caused the molasses to flow more slowly, which made it difficult to rescue victims and conduct the recovery and cleanup.
For the new study, which was presented at the annual meeting of the American Physical Society's Division of Fluid Dynamics in Oregon on Nov. 21, Denver-based fluid dynamicist Nicole Sharp and colleagues explored the physics behind how the flood moved very quickly and caused much damage.
Viscosity And Temperature
The researchers looked at historical accounts and articles from contemporary newspapers as well as studied very old maps of the buildings in the flooded area and historic data from the National Weather Service.
Sharp and colleagues also studied the properties of blackstrap molasses, especially how its flow rate is influenced by temperature. They found that the substance's viscosity, the degree to which it resists flowing, is largely dependent on temperature.
If the weather was warmer when the tank collapsed, the molasses would have flowed farther and thinner and this could have reduced the number of people who got stuck. Half of the victims who died during the flood died because they couldn't get out of the smothering substance.
Sharp said that the data suggest the viscosity of the molasses increased because of the temperature and the high viscosity of the molasses was a crucial factor for doing rescue work.
"It's possible the viscosity of the molasses increased," Sharp said. "That does not sound like such a big difference, but the high viscosity of the molasses was a major factor for rescue work."
Knowing the physics behind the Boston Molasses Disaster is relevant to other accidents affecting the public, such as industrial spills.