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