Final answer:
Raymond needs to create a falsifiable hypothesis to test his idea about the cause of leaves' color change in autumn. A usable hypothesis is testable, logical, and can be disproven by evidence if incorrect, which is an essential step in the scientific method.
Step-by-step explanation:
To test his idea about why leaves change color in autumn, Raymond would need to formulate a falsifiable hypothesis. A hypothesis is a tentative explanation for observations based on available scientific knowledge, which must be both testable and falsifiable. In other words, there must be a possibility to conduct experiments or make observations that could prove the hypothesis wrong if it is indeed not correct.
In science, a hypothesis is not just any guess; it must be logical and align with what is already known about the natural world. Once a hypothesis is established, scientists can perform experiments to test its validity. If it stands up against experimental scrutiny and explains a wide range of phenomena, a hypothesis may evolve into a scientific theory, which is a well-substantiated, comprehensive, and testable explanation. Should a hypothesis be disproven by experimental evidence, it may prompt a reassessment or reformation in light of new findings. This process reflects adherence to the scientific method.