Viewing and Drawing Cells In this lesson you will: • learn to focus a microscope • learn how to properly label a drawing • learn to calculate magnification
Focusing the Microscope There are several steps you must follow when focusing a microscope. It is important to follow these steps in order. Failure to do so could result in broken equipment. This could lead to a smaller bank account for you. Be careful and follow directions! !
Steps to Focusing a Microscope Obtain a slide to view. This could be a prepared slide or a blank one that you have prepared yourself.
Steps to Focusing a Microscope Place the microscope on the table with the light or mirror pointing away from you.
Steps to Focusing a Microscope Raise the body tube by turning the coarse (the big one) focus knob. Revolve the objective lenses until the lowest power lens is directly in line with the body tube. Click it into place. The lens should be directly over the opening in the stage.
Steps to Focusing a Microscope Place the slide to be viewed on the stage. Center the specimen to be viewed over the hole in the stage. Use the stage clips to hold the slide in position.
Steps to Focusing a Microscope Lower the body tube until the low power objective lens almost touches the slide. It will help to look at the microscope from the side instead of through the eyepiece. Be careful not to lower it too far or you will hear glass breaking as the objective lens crushes the slide. Then you will hear the sound of your wallet opening up to pay for the damage.
Steps to Focusing a Microscope You can now look through the eyepiece and see if your object is in focus. If it is not, you should raise the body tube with the coarse focus knob while looking through the eyepiece. Continue to do so until the specimen is in focus. Rat brain section properly focused
Steps to Focusing a Microscope In order to switch to high power, you need to switch objective lenses. When moving to a higher power look at the microscope from the side. Rotate the objective lens until the high power lens clicks into place. Be careful that the lens does not hit the slide. IMPORTANT: Only use the fine focus knob when on high power. The coarse focus knob could go right through the slide!
Steps to Focusing a Microscope That is all there is to it! Follow these simple steps and you are on your way to discovering a world you never knew was out there! Now we will move on to recording what you see.
Drawing What You See There are three parts to drawing the specimen you are looking at. They are: • The actual drawing • The description • The magnification
The Actual Drawing The drawing should be in color and contain as much detail as possible. Do not rush through it. You may not be a great artist but you can do this! Could you draw a picture of the onion cells at the right?
The Description If you are using a properly prepared slide, the description will already be on the slide. If you made your own you will need to describe what it is. Give a short but accurate description. For example, if you are looking at your own hair, don’t just say hair. You should label it human hair. Since all mammals have hair this is an important piece of information.
The Magnification It is also important that you include the total magnification used to view the specimen. To find this you multiply the magnification of the eyepiece (usually 10x) times the magnification of the objective lens. For example: 10x times 40x = 400x Eyepiece objective total lens magnification
Correctly Drawn and Labeled Slide Notice the 3 parts: • picture • description • magnification Specimen: Plant Stem Magnification: 40x
You Are Now Ready To Begin! Follow the directions in your packet that will instruct you what your next step should be. If you need to review any of the steps to focusing you may come back and work through the presentation again. Be careful, have fun, and learn something!