Aristotle declared the existence of only four elements: fire, air, water and earth. It was believed that all matter was made up of these four elements and matter had four properties: hot, cold, dry and wet.

Question

We know now that fire and air are not elements because ____________

Answer 1

We know now that fire and air are not elements because fire is a process of combustion and the release of energy rather than a substance, and air is a mixture of gases, primarily nitrogen and oxygen, rather than a single element. Modern science has established that matter is composed of atoms, which combine to form elements, many of which were not known in Aristotle's time.