Air is a mixture of many gases, water vapours and dust particles.
Air exerts pressure.
Air has mass
Air occupies space.
Air is colourless and odourless.
Some birds can't fly
Flightless birds belong to a group called the ratites.
Typically, flightless birds lack the keel bone, a bone that tightly attaches itself to the pectoral or flight muscles of flying birds.
Ostriches, Cassowaries, Rheas, Kiwis, Moas, and Emus are members.
some birds can fly
Birds have hollow bones that are very light and strong Their feathers are light and the shape of their wings is perfect for catching the air.
Their lungs are great at getting oxygen and very efficient, so they can fly for very long distances without getting tired..
The four forces are lift, thrust, drag, and weight. As a Frisbee flies through the air, lift holds it up. You gave the Frisbee thrust with your arm.
lift
the upward acting force; gravity, the downward acting force;
thrust
he forward acting force; and drag, the backward acting force (also called wind resistance).
drag
the backward acting force (also called wind resistance).
weight
Weight is a force that is always directed toward the center of the earth.
The faster an airplane moves, the more lift there is.When the force of lift is greater than the force of gravity, the airplane is able to fly, and because of thrust, the airplane is able to move forward in flight. According to Newton's third law of motion, the action of the wings moving through the air creates lift.
The first manned flight was on November 21, 1783, the passengers were Jean-Francois Pilatre de Rozier and Francois Laurent. George Cayley worked to discover a way that man could fly. He designed many different versions of gliders that used the movements of the body to control. Samuel Langley was an astronomer, who realized that power was needed to help man fly. The "Flyer" lifted from level ground to the north of Big Kill Devil Hill, North Carolina, at 10:35 a.m., on December 17, 1903.
Planes,helicopters,air balloon,kit,drone,rockets,gliders.