4.1 CELL BIOLOGY
LESSON 3
REQUIRED PRACTICAL 1
Microscope drawings
Learning objective:
all students must measure the objective
of 3 magnifications using a graticule, produce an accurate
microscope drawing of an onion epithelial slide and calculate the
magnification of their drawing.
Rules for microscope drawings:
•
•
•
•
Write a clear heading.
Use a sharp HB pencil.
Draw firm continuous lines and avoid using too much shading.
Include magnification of the lenses you have used
(Magnification of sample = eyepiece lens x objective lens).
• Draw label lines horizontally with a ruler. These must touch the structure
you are labelling but not cross other lines.
• Calculate the magnification of your drawing using the
magnification equation:
Magnification = image size ÷ actual size
(your drawing) (actual size of cell)