I make a popular science video and all the emperors learn from it!

[2. Modern means of transportation. 】

[5. Hot air balloons. 】

[A hot air balloon is a lighter than air, with a large balloon shape on the top half and a gondola on the bottom half.] 】

[The inside of the balloon heats the air, so that it has a lower density than the cold air outside, and acts as a buoyant force to displace the whole body; the gondola can carry passengers and a heat source (mostly an open flame). 】

[Modern sports balloons are usually made of nylon fabric, and the openings are made of refractory materials. 】

【Introduction:】

[It is a balloon that uses hot air as a floating gas.] 】

[At the bottom of the airbag, there is a large opening for cold air heating and a hanging basket. 】

[The density decreases after air heating, and the density is about 0.95kg/m3 when the temperature reaches 100, which is 1/1.3 of air, so the liftoff is not high. 】

[Modern hot air balloons are equipped with simple flight instruments, fuel canisters and blowtorches in the "one-zero-zero" gondola. 】

[When lifting off from the ground, light a blowtorch to heat up the air and inflate the airbag through the opening at the bottom of the airbag.] After lift-off, control the amount of fuel injected by the blowtorch and manipulate the ascent or descent of the balloon. 】

【Historical Development:】

[In the eighteenth century, the Mengfei, a paper merchant in the FA country, invented a hot air balloon in Europe. 】

[Inspired by the constant rise of scraps of paper in the furnace, they experimented with using paper bags to gather the hot gas, so that the paper bags could continue to rise with the air current.] 】

[On June 4, 1783, during a public performance by the Mongolfeld brothers at Place d'Annonet in Lyon, a simulated balloon with a circumference of 110 feet was raised and flew 1.5 miles. 】

[On September 19 of the same year, in front of the Palace of Versailles in Ba Le, the Menggolfeld brothers performed a hot air balloon launch for the king, queen, court ministers and 130,000 Ba Lebanese citizens. 】

[On the afternoon of November 21 of the same year, the Menggolfi brothers carried out the world's first manned flight in a hot air balloon at Fort Muette, Ba Li, flew for 25 minutes, flew over half of Ba Li, and then landed near Yiduli Square. 】

[This flight was a full 120 years earlier than the Wright brothers' plane. 】

[In terms of inflatable balloons, the Robert brothers of the FA country were the first to fly into the sky in a balloon filled with hydrogen. 】

After the Second World War, high-tech made the ball material and heating fuel popularized, and the hot air balloon became a public sport that was not limited by location, simple and convenient to operate. 】

Hot air balloons were once considered the safest flying machines. 】

[Judging from the data alone, the safety factor of hot air balloons is also quite high.] 】

[It is understood that there are about 20,000 hot air balloons in the world.] 】

[Hot air ballooning is becoming more and more popular as a sport, and it has set a record of 34,668 meters in height. 】

【Power:】

[The only power for the flight of a hot air balloon is the wind.] 】

[For a hot air balloon flying around the world, it is necessary to choose a high-altitude current with appropriate speed and direction, and move it accordingly in order to complete the flight efficiently.] 】

[Just like traveling around the world and constantly changing planes, hot air balloons need to take different air currents, and all the pilot has to do is adjust the altitude when "changing air flows", and the altitude of hot air balloons usually reaches more than ten kilometers. 】

【Principle:】

Air is a mass substance. 】

[The same volume of air, with different temperatures, has different densities and masses. 】

[It's like water and ice, and when water freezes, it becomes less dense. 】

[If you press the ice cube into the water, it will always float up, because the ice is less dense than water.] 】

[The principle of balloon liftoff is simply put: the air inside the balloon becomes less dense when heated, and the mass is lighter than the same volume of cold air outside the balloon, so the balloon generates buoyancy and lifts off (like ice cubes floating in water). 】

【Function:】

[1. Military role]

Hot air balloons were originally used for communications and reconnaissance in the military. 】

[In the Franco-Prussian War of 1870, Ba Li was besieged, and the people of the FA used balloons to send people and letters out of the encirclement. 】

[Due to the good lifting performance and long stay time of hydrogen balloons, they are widely used. 】

[However, hydrogen balloons have the disadvantage of being flammable and explosive, so helium balloons appeared in the century. 】

[Hydrogen balloons and helium balloons are mostly used for high-altitude scientific exploration. 】

[2. Sports and tourism]

[After the Second World War, with the development of the economy, the application of high and new technology, the research and development of chemical fibers and the popularization of propane gas, hot air balloon sports have achieved rapid development, hot air balloon is mainly used for aviation sports and sightseeing, due to the simple operation of hot air balloon, the requirements for take-off and landing sites are not high, hot air balloon sports have truly developed into a fashionable and healthy outdoor leisure sport 0 .........]

[In developed countries such as Europe and the United States, there are hot air balloon competitions or activities almost every day, and most of the hot air balloons are owned by large enterprises or funded by enterprises to participate in the competition. 】

[Hot air balloon has become a kind of tourism and entertainment project, and many scenic spots have begun to introduce hot air balloon sightseeing in order to enrich the entertainment activities of scenic spots. 】

[The scenic spot has newly opened up aerial orientation tethered flight and free flight hot air balloon projects, allowing tourists to enjoy the beautiful scenery from high altitude, while also bringing the pleasure of high-altitude drifting. 】

【Homemade method:】

【Tools/Materials】

[1. Large extremely thin plastic tote bag. 】

[2. About 60cm long fine copper wire. 】

[3. Cotton, alcohol. 】

【Procedure/Method】

[1. Take a large extremely thin plastic handbag and cut it flat at the handle. 】

[2. Take a thin copper wire about 60cm long (one of the multiple strands of soft copper wire can be used), and tie the two ends on both sides of the mouth of the convenience bag. 】

[3. A cotton with a small amount of alcohol dipped in a small amount of alcohol on the thin copper wire tundish is made. 】

【...】

"Hot air balloon, I think this is clearly a large Kong Ming lantern. "

"It's a thing that we had during the Three Kingdoms period, but it's a pity that foreigners took the lead and made a hot air balloon that could sit on people. "

"Let's make the Kong Ming lantern bigger, come down and add a big basket, maybe we can also bring people to the sky!"

"Good idea, go try. (If you read a violent novel, go to Feilu Novel Network!)

"Finally found a way to fly! This thing is much more reliable than putting wings on a human body!"

"Let's go, together, there are more people, and we can get together more money. "

“..."