The basic unit of composition of living things (structural) and life activity (functional) is called cells. Cellular composition consists of the nucleus and the cytoplasm that is surrounded by the cell membrane. Cells are largely divided into plant and animal cells, and they have differences such as presence/absence of chlorophyll and cell walls. In the experiment, among plants cells, observe the epdermis cells of the onion through a smartphone microscope, and study their structure and characteristics.