Use a microscope (or a magnifier and close-up photos) correctly and safely to observe small structures, and record clear scientific observations.
A microscope reveals structures far too small to see with the naked eye, but it only works well if used correctly. The main parts to know are the eyepiece (what you look through), the objective lenses (that rotate to change magnification), the stage (where the slide sits), the light source or mirror underneath, and the focus knobs. Total magnification is the eyepiece power multiplied by the objective lens power; a 10x eyepiece with a 40x objective gives 400x magnification.
If a classroom-quality microscope is not available, a strong magnifying glass or a smartphone camera's macro or zoom feature, held very close to a small subject, is a real substitute for this week's skill: careful, close observation and clear recording of what you see. Either way, always start at the lowest magnification, adjust the light, focus slowly, and record what you observe in words or a labeled sketch before moving to higher magnification.
Mastery looks like: They can bring a subject into clear focus starting from low magnification and produce an accurate, labeled record of what they actually observed.
Common stumbles: Jumping straight to high magnification and getting lost; sketching what they expect to see instead of what is actually visible.