Principle After the candle is lit, it will heat the surrounding air. When the surrounding air is heated, its density will become smaller, and the hot air above will rise, forming an upward heat flow. But because the density of paper is relatively light, it will rotate because of the heat flow below. The bigger the flame, the more heated air, the more hot air rising, and the faster the paper rotates, it will automatically dance.
Hot air balloons can fly in the sky, also using this principle. After being heated, the air in the air bag becomes less dense and lighter than the cold air with the same volume outside the air bag, so buoyancy will be generated in the air bag to help the hot ball lift off. Similarly, the more air in a hot air balloon burns, the stronger the buoyancy generated in the airbag, and the higher the hot air balloon can fly.
Precautions: Try to use short candles to avoid unexpected phenomena such as falling in the experiment. Do not cut the spiral paper too long. Spiral paper cut too long is easy to be ignited by the candle below, which will burn and catch fire. Always pay attention to the safety of fire, and try to empty all flammable items on weekends during the experiment to avoid fire accidents. Children's safety awareness is still weak, so parents must accompany them all the time when doing this experiment. Parents take their children to explain and complete this experiment, which can not only play the role of entertainment, but also ensure the safety of children. It is concluded that the spiral paper placed above the candle flame will automatically dance for a while. Simply put, it is to light candles and heat the surrounding air. When the surrounding air is heated, the density becomes smaller, which will generate upward heat flow and push the spiral paper on it to move, so the spiral paper will dance.
This is a very meaningful and easy-to-use scientific experiment. Parents with children can take their children to do this experiment, which can not only exercise their hands-on ability, but also cultivate their research and rigorous scientific attitude, stimulate their curiosity and thirst for knowledge, which is conducive to the development of their brains.