Aerodynamics is the science of how air moves around objects and how objects move through air. When you stick your hand out of a car window, you feel the air pushing against it: that's aerodynamics in action. The shape of your hand matters. Hold it flat like a wall, and you feel strong resistance. Slice it through like a knife, and the air flows smoothly past.

Engineers use aerodynamics to design airplanes, cars, and rockets that move efficiently through the air. A plane's wings are shaped to create lift (the upward force that helps it fly), while its sleek body reduces drag (the air resistance that slows it down). Race cars have aerodynamic designs with low, smooth shapes that let air flow over them quickly, helping them go faster while using less fuel.

Birds are natural masters of aerodynamics. Their streamlined bodies and curved wings let them soar, dive, and maneuver with incredible efficiency. Watch a hawk glide without flapping its wings: it's using aerodynamic principles that engineers spend years studying.

Whether you're designing a paper airplane for maximum distance or watching a cyclist crouch low to reduce wind resistance, you're witnessing aerodynamics at work.