My discovery

On Sunday, I finished my homework. I was idle and had nothing to do. I wanted to play with soap bubbles. I exchanged the soapy water, dipped the plastic tube into a small bottle filled with soapy water, and then blew it with my mouth. A string of bubbles flew out of the plastic tube. It was colorful and beautiful. Extremely. The more I swelled, the more I blew it, and the soap bubbles kept coming out, as if there was a soap bubble. Suddenly, I found a problem: a string of soap bubbles always rises first and then slowly falls down. How is this going? Has the quality of soap bubbles changed? I asked this question to my mother. Mom thought for a while and said, "This... I want to be the same as the principle of a hot air balloon." Is that true? I know that a hot air balloon can fly to the sky because the fuel burns to produce hot air. Can there be hot air in the soap bubble? In order to clarify this problem, I rummaged through the books at home, and finally found the answer in a "100,000 Why": When we blow soap bubbles, the soap bubbles are filled with the gas we blow in. . Unless it is in very hot weather, the gas we exhale is always higher than the air temperature. The quality of the hot air is lighter, so the soap bubbles that have just blown up will rise; but over time, the temperature of the gas in the soap bubbles drops, the volume of the hot air shrinks, and the soap bubbles gradually become heavier than the air, so they slowly fall down. coming. Haha, it turns out that my breathing is the "fuel" of soap bubbles.