A1.Atomic theory has changed a lot over time. Even today, we are developing new technologies that allow us to learn more about our natural world. I am sure that even in my lifetime we will change what we know about atoms. Atomic theory began as a way to explain what matter is made of. Some believed that matter was composed of water, fire, air and Earth. Others thought it was made up of small particles, called atoms, that could not be divided. With more experimentation, we later discovered that atoms were indeed matter. Atoms combine to create elements, the building blocks of matter. We further discovered that atoms are made up of protons, neutrons, and electrons, as well as the structure of the atom.A2a. From the beginning, the idea of ​​the atom was rejected. The most influential men of that time disagreed with Democritus. For a time, people believed that matter was composed of fire, air, water, and earth. Since Democritus had no way to support his hypothesis, his idea was ignored for over 2000 years. It was not until the early 1800s that John Dalton proposed his atomic theory. Although his idea was very similar to that of Democitus, Dalton could actually determine the atomic weight of the first 21 elements. At that time, it was believed that the atom was a solid spherical shape that could not be split. (Atomic Theory) In the late 1800s, JJ Thomson used the cathode ray tube to discover electrons. The cathode ray passed an electric current through a gas. As the current passed through the tube, he realized that the particles were attracted to the positive side of the ray tube. With this discovery, Thomson concluded that it was necessary... middle of paper ......at the time and was able to develop what Democritus had already proposed. (Atomic theory)B1. Attached Model (Understanding Science)Scientific theory initially began as an idea born from personal motivation. It was only later, when new technologies were developed, that scientists were able to carry out experiments that allowed scientists to support their theories. Over the years, scientists have been able to share ideas, allowing others to draw inspiration from their work. It is an ongoing process, there is no beginning or end. One scientist may start with one idea, another may try to build on a different theory, while still others may have started their idea with an unexpected observation. Yet for all of these ideas to become theories, the result must be reproducible, undergo peer review and publication, as well as support the hypothesis..