Ahmed kept a balloon from his birthday for several days until it began to deflate and slowly sink to the ground. He wondered how the balloon was losing its ability to float. He decided to use his

Ahmed kept a balloon from his birthday for several days until it began to deflate and slowly sink to the ground. He wondered how the balloon was losing its ability to float. He decided to use his Physical Science textbook to get more answersWhat chapter should Ahmed read to learn more about how things function or behave?
laws
theories
hypothesis
observations