How do swallows know when it s going to rain?

Swallows can ** The reason for the arrival of heavy rain: before the heavy rain, the air becomes very humid, which will wet the wings of insects flying in the sky, so the wings of insects cannot stretch and fly freely, so they have to fly slowly or crawl along the ground. Due to the air current, the air pressure before the rain will decrease slightly, the air will become thinner, and the oxygen content will also decrease.

Insects respond sensitively: the decrease in oxygen content causes many insects, such as dragonflies, that normally fly at mid-altitude altitudes to congregate near the ground. In addition, due to the humidity of the air.

As the air pressure increases, the air pressure decreases, and some small insects that live in the soil will also feel very uncomfortable, so they will also climb from their burrows to the ground to breathe. In other words, before heavy rain, a large number of small insects gather at low altitudes on the ground and adjacent to the ground, so swallows often fly low to hunt.

In addition, before the heavy rain, the air flow in the atmosphere is very disordered, which makes it difficult for swallows to get the right wind, so it is difficult for them to spread their wings and fly low. Moreover, the swallows in the low flight are often high and low, flying uncertainly, sinking and rising, skimming the water and cutting waves. Therefore, low flying swallows often indicate that heavy rain is coming.

The humidity in the air before the rain makes the wings of the insects wetter, so the ability of the insects that feed the swallows to fly is greatly affected, and they can only fly close to the ground, so the swallows also reduce their flight altitude.

Because some of their olfactory habits are very sensitive, they also react when stress is low, so they know it's going to rain.

It is because of the change in atmospheric pressure of the weather, and the low air pressure causes swallows to fly around, because swallows are the most sensitive to the air pressure field.

1. The principle of swallows flying low: when there is a lot of water vapor in the air, the air pressure in the air will become lower. When the air pressure becomes low, the survival of the flying insects will be affected to a certain extent, so the flying insects will fly up from the ground and hover at a low altitude, and wait for the air pressure to rise before landing, and at this time the swallows will fly low.

Therefore, it can also be said that swallows fly low because of low air pressure.

2. Explanation of air pressure: Air pressure is the atmospheric pressure acting on the unit area, that is, the gravitational force that is numerically equal to the vertical air column that extends upward to the upper boundary of the atmosphere on the unit area. The famous Magdeburg Hemispheric Experiment proves its existence.

The international unit of air pressure is Pascal, abbreviated as Pa, and the symbol is Pa.

It was wet weather, and the rain told the swallows that it was going to rain.

The reasons why swallows fly low before rain are:

1.Whenever the weather is about to rain, due to the sharp increase in the water vapor content in the air, most insects have wet wings and cannot stretch and fly freely, and can only crawl along the ground; Some insects that live in the soil crawl out of their burrows to breathe fresh air due to the decrease in air pressure and the increase in temperature, which gives the swallows a great opportunity, so the swallows often fly low to hunt before the rain.

2.Before the weather is about to rain, the airflow is more disordered, and the swallow can not get the right wind to make it fly high, so it often rises high and low in flight, rises and rises at first, skimmes the water and cuts the waves, and flies uncertainly.

3.In order to avoid being hit by lightning, rain and hail, swallows will also fly low before the rain.

Swallows fly low before rain because of the air currents and also to prey on insects.

Because the air humidity is high before the rain, the wings of insects flying in the air are damp. In this way, the insects have more difficulty flying and their flight altitude is lower than on a sunny day. These insects are the food of the swallows, so if the swallows want to catch the insects, they must lower their flight altitude to catch them.

In addition, when it is about to rain, the air currents in the air are turbulent, and swallows are affected by the air currents so they fly very low.

Signs before the rain

1. Ants will move: Ants who dig holes in the ground and live will run away before the rain when they feel that the hole will be flooded if it rains.

2. Earthworms come out of holes: The ground is wet and soft, and earthworms will crawl out of the ground, indicating that it will rain.

3. Sky: The air humidity increases, the air pressure decreases, the sky is dark, the clouds are thick, and sometimes there will be thunder, lightning and wind.

4. The fish will float to the surface to breathe: the air pressure in the water is low, and the oxygen dissolves less, so the fish will float to the surface to breathe.

5. Puppy tongue: There are no sweat glands on the dog's body, and the heat can not be dissipated by pores in the hot summer, only by opening the mouth and pulling the tongue to dissipate heat to maintain a constant temperature.

6. Snake aisle: Most snakes hide in the hole during the day, and go out at night to forage, drink, bathe, molt and other activities, but the weather is particularly humid and stuffy when it will also be forced out of the hole, therefore, the snake out of the hole during the day is a sign of rain.

Before the rain, the air humidity increases, when the air humidity exceeds the critical value, a part of the water vapor liquefies on the solid surface, including the wings of insects, insects have no muscles, the wings become humid and heavy, and it is more difficult to wield, so they cannot fly high; Birds, on the other hand, have developed muscles, so their flight is not affected and they still fly freely. The rain is often preceded by wind, so many birds return to their nests to take shelter.

When the swallows fly at low altitude, it is a sign that it is about to rain. This is a scientific judgment.

Swallows fly low to make it rain. Because before the rain, the air is relatively humid, and the small insects also fly very low, so the swallows also fly very low to catch insects.

If the swallow flies low, it means that there is more moisture in the air, so the small flying insects fly relatively low, and the swallow will fly low, and it may rain.

The swallows flew low, and some of them were about to slip to the ground, and it was going to rain.

Before the rain, the air pressure in the area where the rain is about to fall will drop slightly due to the action of the air current. At lower air pressures, the air becomes thinner and the oxygen content decreases. Because of the decrease in oxygen content, many small flying insects such as dragonflies that usually stay in the middle of the air gather near the ground, and swallows also fly low to prey.

In ancient times, it was not as good as now, and precision instruments could be used to capture the changes in the wind and clouds and make weather forecasts. In the long-term production practice, in addition to observing the celestial phenomena, the ancient Chinese working people also observed the weather by observing the animals and plants around them, thus summing up a large number of meteorological proverbs.

Before the rain, first, the air pressure increases, and the swallows fly higher again, which is very laborious.

Second, small insects in the air have damp wings and can only fly at low altitudes. Swallows just shuttle back and forth, [a fat meal in the air]. Eat hard!

So, it will rain when the swallow flies low.

Because the air is humid before the rain, small insects can only fly low or walk on the ground. Therefore, if the swallow flies low, it will be easy to catch the insect.

It's going to rain.

Swallows fly low.

The humidity in the air is particularly high before the rain.

As a result, a layer of water beads forms on the wings of many small insects.

As a result, it will fly slower and fly lower.

The swallow will take advantage of this time to fly lower.

Catch more bugs.

Because when it is about to rain, the weather is humid, and the wings of small insects are also very wet, which is only suitable for walking on the ground or flying in low places, and swallows can eat small insects by flying low, so it will rain when swallows fly low.

In the late spring and early autumn season, sometimes in the afternoon or evening, it is common to see flocks of swallows flying lower and lower, or gliding rapidly against the ground, or flapping their wings and lingering in place. When this phenomenon occurs, it indicates that the day is about to rain and increase sharply, the wings of most insects are wet, can not stretch and fly freely, can only crawl along the ground, some insects that live in the soil due to the decrease in air pressure, the humidity increases, it is very uncomfortable to live in the soil, and they have also climbed out of the hole to breathe the air, this is a good time for swallows to hunt for food, so swallows often fly low to catch. In addition, before the weather is about to rain, the airflow is more disordered, and the swallow cannot get the right wind to make it fly high, so it often rises and falls in flight, sinks and rises again, skims the water and cuts the waves, and flies uncertainly.

Therefore, the low flight of swallows is often a sign that the sky is about to rain.

Swallows flying low means it's about to rain.

Because when it rains, the swallows will have a lot of air pressure if they fly higher up.

Because the wings of the little insects are stained with small droplets of water before the rain, they can't fly high, and the little swallows will fly low.

Because the air pressure increases before the rain, it will be difficult for swallows to fly during the evening rush hour.