Microscope Review Created by J. Cook

The Compound Microscope Have students name parts. State a function and have students say the number. Ask if there are any parts they don’t quite understand just yet.

The Compound Microscope Have students name parts. State a function and have students say the number. Ask if there are any parts they don’t quite understand just yet.

Preparing a wet mount slide What are the steps? Place one or two drops on slide. Cover with slip at 45○ angle. Gently press down to remove air bubbles.

Sketches List the 6 components of a sketch. Name the object Write the total magnification. Complete a detailed sketch. Use pencil. Label important parts. Show the measurement (size of object). Make detailed written observations of things that can’t be shown in sketch: descriptions of movement/behavior etc. . Also ask students to model each component and to explain where they should complete them.

What is the benefit of each power? LOW: Scanning. Finding objects. Viewing a large area of the slide. MEDIUM: Greater detail than low, but can still see a fairly large area of slide. Easier to follow moving organisms than on high power. HIGH: Greatest magnification to see the most detail. Ask students if they have more to add.

Using High Power Get object in sharp focus on low, then medium power before going to high. The object must be centered. Once on high power only small adjustments should be needed.Use only the fine adjustment knob. Often requires more light than low or medium power. Objects at slightly different levels will not all be in focus at the same time. If you “lose” an object on high power you will have to go back to medium or low to find it again. How did this work? Any problems? Any other suggestions?

Trouble Shooting How do you focus an object? Always start on low power Use Coarse adjustment first. Then use fine adjustment What if no light is coming through? Turn on the microscope and all power strips. Adjust the diaphragm Clean the lenses Make sure the nose piece is “clicked” into place. Any other problems? Any other suggestions?

Actual Field Diameters of Our Microscopes Write these numbers down in a safe place. You will need to know them all year long! POWER MAGNIFICATION FIELD DIAMETER Low 40X 4500 µm Medium 100X 1800 µm High 400X 450 µm Students MUST know these values all year long and are now expected to use them to determine the size of objects for all sketches.

Measuring under a microscope How is total magnification calculated? The objective lens multiplied by the eye piece What is the “field diameter”? The distance across the lighted circle you see when looking through the microscope. What is the general formula used to determine the size of an object? The field diameter divided by how many of that object you estimate would fit across the diameter. Practice! Use some examples… have them find actual measurments.

The Dissecting Microscope Ask students to state the name and function of different parts.

Comparing and Contrasting the microscopes List some similarities for both microscopes. State some differences for the Compound microscope. State some differences for the Dissecting microscope. (Include purpose, type of object to view, appearance of objects etc.) Student should list similarities like: Both magnify, have coarse adjustment, have low and high power, have a bottom light. Differences for Compound: one eye piece, greater magnification, object appear upside down and backwards, can only view transparent objects, less depth, fine adjustment. Dissecting differences: Two eye pieces, only coarse adjustments, top light, objects move in the same direction as moved, less magnification, can view opaque objects and larger objects.