What principles of physics do swallows use when gliding?

When a swallow glides, its wings tilt backward (the leading edge is high and the trailing edge is low), and due to inertia, the air cannot move in time, resulting in high air pressure in the lower part of the wing and low air pressure in the upper part of the wing. There is a pressure difference between the upper and lower wings, and this pressure difference is parallel to the direction of the Earth's gravitational force, which is the lift of the swallow as it glides.

But until now, people have not fully understood why birds are able to fly in the sky. Here are some of the examples that have been researched and concluded.

When birds vibrate their wings in the air, the front of the wings squeezes the air into the air in front of them, and the pressure of the air in front of them rises, while there is no air behind the wings, forming a cavitary area, attracting the surrounding air to fill it, and the air pressure gradually rises. As the wings continue to move, the air in front of the wings gradually flows along the periphery of the wings to the low-pressure area behind them under pressure, filling the cavities and forming a circulation around the wings. The pressure difference between the front and back of the wings breaks the air balance between the front and back of the wings, and this pressure difference causes the wings to lift.

When the lift provided by the wings exceeds the weight of the bird, the bird takes off. Without the creation of a cavity on the back of the wings (i.e., vacuum generation), birds would not be able to fly with the help of this cavity force (i.e., vacuum zone force).

To put it simply, birds induce a vortex ring similar to half a smoke ring on the upper side of the wings when flying, and strengthen the flow velocity on the inner side of the vortex ring by spreading their wings, reduce the air pressure, and the two ends of the vortex ring are attached to the wings to form a strong lift, so that the bird can fly.

Swift flying swallows.

It's not always flying, there's a word called gliding, you can fly far by gliding for a while, that's how the principle of gliding comes from.

Because it's too slow.

Swallows are migratory birds, and they migrate with changes in the climate. In winter, the temperature in the north is low, which is not suitable for them to survive, so they have to migrate south. When the spring flowers bloom, they will return from the south to the north to have children and live and work in peace and contentment.

Moreover, swallows feed on insects and are accustomed to preying on flying insects in the air, but they are not good at searching for insect food in tree crevices and ground gaps, and there are no flying insects for swallows to hunt in the northern winter. The scarcity of food prompted the swallows to have to make a great migration from autumn to spring every year to get a wider living space.

Reproductive Biology

Swallows generally breed in April 7 months. House swallows nest under the eaves of a farmhouse. The nest is made by gluing mud and grass stalks with saliva, and is covered with fine weeds, feathers, rags, etc., and some Artemisia annua leaves.

The nest is dish-shaped. The Closed Talk Brigade breeds 2 litters per year, mostly from May to early June and from mid-June to early July. Each clutch lays 4 6 eggs.

The second litter is less and less at 2 5 pieces. Milky white eggs. Male and female co-incubate eggs. 14 15 days old birds out of the shell, the parent birds are fed together. The chicks fly out for about 20 days, and after feeding for another 5 to 6 days, they can feed themselves. The food is all insects.

Of course, the swallow can be smothered to glide and fly like an eagle, but the swallow flies relatively low, unlike the eagle, which can fly for a longer time than the eagle with a stable high airflow, and the swallow also uses a variety of air currents during the flight.

Summary. When a swallow flies at a constant speed, it is only subjected to gravity because the air flow resistance and air resistance it experiences is negligible and negligible.

When a swallow flies at a constant speed, it is only subjected to gravity because the air flow resistance and air resistance it experiences is negligible and negligible.

I'm still a little confused, can you be more detailed?

As the swallow flies at a constant speed, there is no force other than the gravitational pull (gravity) of the earth that affects it. Flying at a constant speed means that the velocity does not change, so according to Newton's first law - the velocity of an object in a free state will remain the same, because the object remains stationary or moves in a straight line at a uniform speed without force. The velocity of the orbital moving object is always in equilibrium with the gravitational force, because the swallow has reached the state of uniform jujube velocity, the gravitational force and the drag force are equal, and the upward thrust will not be affected by the downward traction, only the presence of gravity.

Therefore, the swallow is only affected by gravity during its flight, while maintaining a uniform speed and flying in a straight line.

You're in the sixth grade, right? I've read your winter vacation homework, and one child answered it like this, but it doesn't seem to have any basis, you can refer to it.

1. The two wings fluttered, and when they went up and down, they took off.

2. The wings of chickens are like human hands, and when they fight, the wings flap back and forth to hit each other.

3. Eagles, swallows, geese, etc.

4. Because their wings are degenerate.

How do you flap your wings when you are fighting a chicken?

The wings are spread, and the neck is erected and the crown is a little angry.