Secondary Lesson Plan: Observing with a Compound Lens Microscope
Grade 10 Biology
Objective
Students will be able to bring into focus the lens on a compound light microscope and
make an accurate observation of a plant cell.
Standard
State Science Framework: Students will be able to use the tools of scientific inquiry.
Procedures
Clarify Goals and Establish Set
Tell students that today they are going to learn how to focus a lens on a compound light
microscope and how to make an accurate observation using the microscope. Explain that
this an important skill needed to investigate various scientific phenomena. To get
students thinking about the process of focusing and viewing through a microscope, relate
this process to other viewing processes they may be familiar with (e.g. viewing through
the lens of a camera, of a camcorder). Ask what kinds of problems do we sometimes face
when adjusting lenses?
Demonstration
1. With a PowerPoint slide, show students the various parts of a microscope and
explain the functions of each part.
2. Take a real microscope and demonstrate how to focus the lens, how to center your
eye, and how to view an object on a slide.
3. Check to see if students understand what has been demonstrated in Steps 1 and 2.
4. Hold up a slide that has a plant cell on it. Again demonstrate how to focus the
lens and view the cell on a standard slide. If possible demonstrate how the cell
should look using a PowerPoint slide.
Guided Practice
1. Have students work in pairs and tell them you want them to practice focusing the
lens and viewing the plant cell. Each pair of students should have a microscope
and a pre-prepared slide.
2. Circulate around the room helping each pair. Check for correct procedures and
provide feedback as required
3. Continue the practice until all pairs report that they can focus the lens and view
the cell accurately. Get them to share what they see.
Check for Understanding and Provide Feedback
1. Have two or three pairs demonstrate to the whole class how they focused the lens
and explain what they see.
2. Provide feedback to each pair. If they are doing it correctly say “that is correct.” If
they make errors, point out the errors and demonstrate the correct procedure.
Extended Practice
1. The following class period, show students how to prepare their own slide.
2. Then, let them practice (without your help) focusing the microscope and viewing
the slide.
Assessment
In this case, the extended practice serves as the assessment. Later, students could be
asked to perform the same task in a more controlled testing situation or they could
describe the process on a written test.
Differentiation
About anyone can be taught to perform this task. Time, however, will be a critical
variable for particular students to master the skill. Be prepared to give some students
more time and/or to provide more hands-on assistance. Students who master the skill
quickly could be asked to help those who are still having trouble.