The first model of the atom was developed through scientific experimentation and data analysis with water vapor and gases. observation of the light emitted by elements when they are heated. thinking about the smallest particles of matter without experimenting. analyzing the effects of a magnet on the path of a cathode ray.

The first model of the atom was developed through thinking about the smallest particles of matter without experimenting. This is known as the Dalton's atomic theory, which was proposed by John Dalton in the early 19th century. Dalton's atomic theory proposed that all matter is composed of indivisible atoms, and that atoms of the same element are identical in mass and properties. This theory was developed based on his observations and experiments with chemical reactions, and it laid the foundation for the development of modern atomic theory.