Welcome to the microscopic world. In our previous lessons, we stayed at the macroscopic level โ observing the color, state, or combustion reactions of substances (such ascharcoal burning in oxygen). But today, we will break the intuition that "matter is a continuous whole" and establish the microscopic concept ofatomsandelectronsconstituting matter.
1. The Microscopic Nature of Macroscopic Phenomena
When we add a small amount of fuchsine to water (Experiment 3-1), we observe the red color gradually spreading out. This proves that matter is made up of extremely tiny particles in constant motion. Just like the3D model of carbon nanotubesshown on the unit cover, each sphere represents a microscopic particle.
2. The Eye of Technology: Scanning Tunneling Microscope (STM)
Although individual particles cannot be seen with the naked eye, modern technology uses thescanning tunneling microscopeto let us "see" benzene molecules (Fig. 3-2) and even the arrangement of individual silicon atoms (Fig. 3-3). This confirms theatomsobjective existence of microscopic particles.
Core Connection: From Properties to Structure
Why can some substances be used forseawater desalination, while others can support respiration? It all depends on their microscopic composition. As we learned before with the decomposition of hydrogen peroxide: $2H_2O_2 \xrightarrow{MnO_2} 2H_2O + O_2$, the essence is the rearrangement and recombination of molecules.