Escherichia coli, Staphylococcus aureus... Even though these bacteria cannot be directly observed with the naked eye, they are closely related to our daily life. Only through scientific methods to identify different bacteria species can we better prevent and make use of these microbes. On December 29th, the 11th-grade students of biology class carried out the experiment "Gram Stain". Based on the differences in the composition of bacterial cell walls, the Gram stain method was applied to distinguish different bacterial species.

In the experiment, the teachers first demonstrated the experimental procedures in detail, and then the students prepared slides of the gram-negative bacteria E. coli and the gram-positive bacteria S. aureus, and observed their shape and color under a microscope. Finding that different bacteria showed distinctive patterns under the microscope after they had been stained, the students were excited and amazed. Finally, under the guidance of the teacher, the students further compared and discussed the different experiment results. Through the association of experimental results and the underlying principles, this practical exploration in the micro-world not only strengthened the students' grasp of the knowledge of bacterial structures, but also cultivated students' logical-thinking ability and literacy in the life sciences.

(Written by Mengli Wang Pictures by Mengli Wang Reviewed by Qian Zuo)