Who was the first to prove that air has weight, and how to prove that air has weight?

Galileo In ancient times, although some philosophers of ancient Greece, such as Plato, had assumed that air had weight, they could not weigh it, so people always believed that air had no weight. In the 17th century, the great scientist Galileo Galilei conducted experiments and proved that air has weight.

The earliest experiments were simple, with Galileo pumping a large glass with an air pump, that is, pressurizing the bottle to fill it with more air. At this point, weigh it on a scale and write it down. Then, when the bottle is opened, the extra air escapes, and then the weight is weighed.

As a result, the bottle became lighter. Why is that? Galileo believed that it was because the air that was in and out of it.

Obviously, the weight saved should be the weight of the air that runs out.

Next, Galileo did another experiment to find out the specific gravity of the air. He finds a cylinder that fills it with air and does not let it escape, and then fills the cylinder with water so that it occupies three-quarters of the cylinder's volume. In other words, the air in the cylinder is compressed to a quarter of its original volume.

The weight of the water put into the cylinder is l kilograms, but after the cylinder is weighed, the weight exceeds the weight of the water plus the weight of the original cylinder. This excess is exactly three-quarters of the volume of air compressed by water in the cylinder. In this case, simply divide this excess by the weight of water to get the specific gravity of the air.

Galileo calculated that the weight of air was only one quarter of the weight of water, that is, grams per cubic centimeter, but this figure was inaccurate, because later people used precise experiments to determine the weight of l cubic centimeters of air in the layer of air close to the ground.

In ancient times, air was thought to be a simple substance, and in 1669 Mei Yu deduced that the composition of air was complex based on experiments with candle burning. In 1700, German Stario put forward a universal chemical theory, which is the "phlogiston theory". He believed that there was an invisible so-called phlogiston, which existed within combustible substances.

For example, when a candle burns, phlogiston escapes when burning, and the candle shrinks and collapses into ashes. However, the phlogiston theory cannot explain some phenomena in nature after all, and it has serious contradictions.

The first is that no one has ever seen the existence of "phlogiston"; Second, if the mass of the metal increases after combustion, then the "phlogiston" must have a negative mass, which is inconceivable. In 1774, the French chemist Lavoisier proposed the oxidation theory of combustion, and only then did he deny the phlogiston theory. In the process of experimenting with the combustion of lead, mercury and other metals, Lavoisier found that a part of the metal turned into a colored powder, and the volume of air in the bell was reduced by 1 5 of the original volume, and the remaining air could not support the combustion, and the animals would suffocate in it.

He called the remaining 4 5 gases nitrogen (meaning non-life-providing), and it was only after he proved that the gas prepared by Priestley and Scheler from the decomposition of mercury oxide was oxygen, and the composition of the air was determined to be nitrogen and oxygen.

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1. One balloon is inflated, and the same other is not inflated, and placed on both sides of the scale; You know that the air has weight, and the inflated side is heavy.

2. Tie the balloon with a rubber band, let the balloon go vertically, and then measure the length of the rubber band with a ruler; Then inject air into the balloon, also tie it with rubber and go vertically downward, measure the length, the latter method measures the length of the rubber band longer than the previous one, indicating that the air has mass.

3. Fill enough air in two plastic bottles, close the caps, and place them at both ends of the balance to balance the scale. If the lid of one of the bottles is opened, the air in this bottle decreases, and the balance is unbalanced, proving that the air also has mass.

Right. Air density.

It is a unit volume at a certain temperature and pressure.

The mass of air is the density of air, and any object has volume Air also has volume, but for a certain amount of air, the volume will also change when the pressure changes, so when the external conditions are constant, the volume of air is also fixed.

Therefore, when the external conditions are constant, the volume of air is also fixed, there is a formula pv t=r, r is constant, p is pressure, v is volume, t is temperature, that is to say, temperature, when the pressure is constant, the volume of air is fixed.

This statement is not true. Because there is a huge difference in air density between the plain and the plateau, that is, there is no standard reference frame for air density, it is not correct to say that there is a certain volume of air; Because the air floats above the ground, the air has mass but no weight, so the argument that air has weight is not valid.

The first scientist to prove that air has mass was: Galileo.

The earliest test was very simple, Galileo used an air pump to fill a large glass, that is, to use the method of pressurization to fill the bottle with more air, at this time, weigh it with a scale, write it down, and then, open the mouth of the bottle, the void grinded some more air and ran out, then weighed again, as a result, the bottle became lighter, and the experiment proved that the air has mass.

Characteristics of the air:

It can occupy space, can flow, has no fixed shape, is easy to compress, and is very lightweight.

Galileo introduced:

Galileo is an Italian mathematician, physicist, astronomer, pioneer of the scientific revolution, Galileo invented the pendulum needle and thermometer, has made great contributions to mankind in science, is one of the founders of modern experimental science, played a major role in the development of natural science and world view in the 17th century, experimental science from Galileo and Newton is the beginning of modern natural science.

Galileo's Experimental Science:

In his research, Galileo attached great importance to the role of observation and experimentation, and he was good at formulating hypotheses based on observations, and using mathematical tools to make deductive reasoning to see whether it was consistent with experiments or observations.

The quality of the air:

1 kilogram of air is a cubic meter, a pound of air is equal to a cubic meter, air is a mixture of gases, helium accounts for 78%, oxygen accounts for 21%, and other gases account for less than 1%.

Kites, also known as paper kites in ancient times.

Invented by the Chinese about 2,000 years ago, it is one of the earliest heavier-than-air aircraft that appeared in humans, and Westerners used the kite to overcome its own weight and continue to fly in the air, and invented the aircraft with the help of the principle of aerodynamics and the principle of lift.

The kite was invented by the ancient Chinese working people in the spring and autumn period of Dongxiao and Zhou, for more than 2,000 years, according to legend, Mo Zhai made wooden birds out of wood, which is the earliest origin of human kites. It was not until the Eastern Han Dynasty that Cai Lun improved papermaking and began to make kites with paper, called "paper kites touching and taking", and by the time of the Northern and Southern Dynasties, kites began to become a tool for transmitting information.

At 0 degrees Celsius and one standard atmosphere (PA), the density of air is . Air has density, and in the case of volume, the mass is equal to the density multiplied by the volume, and there is mass.

The composition of air includes: the main components are nitrogen and oxygen, and there are very small amounts of radon, helium, neon, argon, krypton, xenon and other inert gases and water vapor, carbon dioxide and dust and other zendan. Tease the grind.

Air at room temperature is a colorless and odorless gas, while liquid air is a light yellow liquid that flows easily. Generally, when the air is liquefied, the carbon dioxide has been removed, so the composition of the liquid air is oxygen, nitrogen and argon, and the content of other components is very small, which can be omitted.

Summary. Air has weight.

Does air have weight.

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Air has weight.

Under standard conditions (0, 1 standard atmosphere (1atm)), the density of air is about. That is, under standard conditions, each cubic air weighs kilograms.