Whether it’s racing down Pratt Street or pulsing through the open ocean on the hunt for dinner, reaching maximum speed is all about physics. Above ground, vehicles have an initial thrust from the motor to propel them forward. To build speed, the exterior of cars are designed to be as aerodynamic as possible, meaning they minimize drag and friction to not overexert the engine.
Although the Indy Cars expected at the Grand Prix of Baltimore this weekend can reach speeds of up to 230 mph, they are no match for jet engines! It’s hard to believe that all that weight and metal can soar through the air at speeds exceeding 2,000 mph. Getting a jet off the ground involves three major factors: (1) the engine provides thrust; (2) the wings provide lift to counter gravity; and (3) the aerodynamic shape cuts friction and drag.
These principles also apply to sharks and our other fast fish friends that live in the open ocean. The caudal (tail) fin provides initial thrust by swaying back and forth, pushing the water and propelling the animals forward. Like the wings of an airplane, the pectoral (side) fins give the animals the needed lift to keep them moving and counter gravity. And their smooth, streamlined bodies reduce as much friction and drag as possible!
Sand tiger sharks are built for continuous swimming. They feed primarily on fish and need to be able to move quickly. Their big caudal fins help push them forward through the water all day without exhausting their energy. Their horizontal pectoral fins give the sharks the perfect shape to lift and stay above the ocean bottom. The pectoral fins are also critical to helping them get water over their gills so they can breathe. Unlike fish species, sharks don’t have swim bladders to keep them afloat, so it takes a lot more work to fight the drag of water molecules!
Over time, humans have adapted to swim, and in the case of Olympian Michael Phelps, pretty quickly, but we are in no way built for it. We don’t have webbed feet, fins, or a streamlined body made for the water. Phelps, who holds the fastest swimming speed record, maxes out at just under 5 mph. Sharks, on the other hand, can hurdle toward prey at recorded swimming speeds of up to 46 mph!