The Microscope

The History Zacharias Jansen The “First” Microscope

The History Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses Anthony van Leeuwenhoek Robert Hooke Hooke Microscope

How a Microscope Works Convex Lenses are curved glass used to make microscopes (and glasses etc.) Convex Lenses bend light and focus it in one spot.

The Parts of a Microscope

Body TuBody Tube Nose Piece Objective Lenses High Power Stage Clips Diaphragm Light Source Ocular Lens Arm Stage Coarse AdjCoarse Adj. Fine Adjustment Base Skip to Magnification Section

Body Tube Diagram

Nose Piece The Nose Piece holds the objective lenses and can be turned to increase the magnification Diagram

A. Ocular Lens/Eyepiece Magnifies the specimen image Diagram

B. Objective Lenses Increase magnification Diagram

C. Stage and Stage Clips Supports the slide/specimen and holds the slide/specimen in place on the stage. Diagram

D. Diaphragm Controls the amount of light on the slide/specimen Turn to let more light in or to make dimmer. Diagram

E. Light Source Projects light upwards Diagram

F. Base Supports the microscope Diagram

G. Arm Used to support the microscope when carried. Diagram

H. Coarse Adjustment Knob Moves the objectives up and down (quickly) for focusing your image Diagram

I. Fine Adjustment Knob This knob moves the objectives SLIGHTLY to sharpen the image Diagram

Magnification

Comparing Powers of Magnification We can see better details with higher the powers of magnification, but we cannot see as much of the image. Which of these images would be viewed at a higher power of magnification? AB

Magnification To determine your magnification…you just multiply the ocular lens by the objective lens Objective Lenses have their magnification written on them. Ocular lenses usually magnifies by 10x

Magnification on OUR microscope 1. What is the magnification of OUR ocular lens? 2. What is the magnification of OUR low power objective lens? 3. Of our MEDIUM power? 4. Of our HIGH power? 10x 4x 10x 40x

Let’s Multiply the FUN! If you are looking at an object under LOW power, what is the total magnification of the microscope? Multiply the ocular lens (10x) by the objective lens (4x) to get total magnificiation. (10x) x (4x) = 40x

Caring for a Microscope Clean only with a soft cloth/tissue Make sure it’s on a flat surface Don’t bang it Carry it with 2 HANDS…one on the arm and the other on the base

Carry a Microscope Correctly

Using a Microscope Start on the lowest magnification Place slide on stage and lock clips On LOW power, use the coarse adjustment to move the stage up to its highest setting Slowly move the stage down until you start to see something. Focus and center it BEFORE moving to a higher power Adjust light source (if it’s a mirror…don’t stand in front of it!) Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! –Use fine adjustment to focus

Clicker Time!!! WOO HOO! I love CLICKERS!!!

If you are looking at an object under low power, what adjustment should you use? 1.Fine 2.High 3.Low 4.Coarse

If you are working on high power, what adjustment should you use? 1.High 2.Low 3.Fine 4.Coarse

If you are working on Medium Power, what is your total magnification? 1.4x 2.10x 3.40x 4.100x 5.400x

Which objective lens should you always start with? 1.Low 2.Medium 3.High

How to make a wet-mount slide … 1 – Get a clean slide and coverslip from your teacher. 2 – Place ONE drop of water in the middle of the slide. Don’t use too much or the water will run off the edge and make a mess! 3 – Place the edge of the cover slip on one side of the water drop. You do not need to use the stage clips when viewing wet-mount slides! 5 – Place the slide on the stage and view it first with the low power objective. Once you see the image, you can rotate the nosepiece to view the slide with the different objectives. 4 - Slowly lower the cover slip on top of the drop. Cover Slip Lower slowly

Using a Microscope Start on the lowest magnification Place slide on stage and lock clips On LOW power, use the coarse adjustment to move the stage up to its highest setting Slowly move the stage down until you start to see something. Focus and center it BEFORE moving to a higher power Adjust light source (if it’s a mirror…don’t stand in front of it!) Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! –Use fine adjustment to focus