The Physics of Bird Flight

The process by which a bird takes flight is majestic. However, it can be explained by simple physics – it is a matter of the bird's thrust and lift forces overcoming gravity and friction. Its flight begins with a conversion of the stored energy in its muscles into kinetic energy. Newton's Third Law, stating that every action has its equal opposite reaction, explains how the bird's motion gets it off the ground once it starts flapping. Air pushes back on the bird's wings flapping with an equal opposite force to create enough lift to push it upwards. Wings have to return to their initial position in order to repeat the flapping motion, but they are hinged and can change the angle of attack on the up stroke to reduce the wing's surface area and create less opposite force pushing down (Obermeier, 2022).

Once a bird has ascended, it transitions from a flapping motion to a gliding one. This position, assisted by the bird's biological construction and the forces of physics, is called airfoil, and is what airplanes and boomerangs are modeled after. Wings have less surface area on the top with tapered back ends, and their feathers are secured together by hooklets that help them hold this airfoil position comfortably (Obermeier, 2022). The air above wings stretches out, meaning there is lower air pressure above the wing than below it. Since air of higher pressure always moves towards air of lower pressure, the air under the wings moves upward and lends the bird lift even when its wings are still. Birds' bodies are also notably light-boned and streamlined, making them extremely aerodynamic, which helps mitigate frictional drag acting against their thrust and lift (UNC, 2010).

References

Obermeier, L. (2022, September 19). The Physics of Flight. Schlitz Audubon Nature Center. Retrieved November 5, 2024, from https://physicsofflight.webnode.page/the-mechanics-of-flying/

UNC Chapel Hill. (2010). Physics Of Flight: Birds. Retrieved November 5, 2024, from https://physicsofflight.webnode.page/the-mechanics-of-flying/

World Wildlife. (n.d.). Bird Flying [Photograph]. Stock Snap.

     https://stocksnap.io/photo/bird-flying-M2XM8CRVNI