Transcript Microscope
Warm Up: • What is the function of this organelle? • Is it found in animal cells, plant cells, or both? Microscope • The human eye has a resolution in the order of 100 um which is about the thickness of a hair the microscope has unveiled the secrets of nature Compound microscope has two systems of lenses for greater magnification 1) the ocular, or eyepiece lens that one looks into and 2) 2) the objective lens, or the lens closest to the object Parts of Microscope • • • • • Ocular Lens: the lens at the top that you look through. They are usually 10X. Tube: Connects the eyepiece to the objective lenses Arm: Supports the tube and connects it to the base Base: The bottom of the microscope, used for support Illuminator: A steady light source or mirror • Revolving Nosepiece: part that holds two or more objective lenses and can be rotated to easily change power. • Objective Lenses: Usually you will find 3 or 4 objective lenses – 4X, 10X, 40X and 100X powers. Magnification • Multiply power of ocular lens by the power of the objective lens • Example: – If you are looking at a cell under the 40x objective • 10 (ocular) x 40 (objective)= 400 times magnified You try… • If you are looking at a red blood cell under the 100x objective, how many times is it magnified? • 10 x 100= 1000 Diaphragm : rotating disk under the stage • has different sized holes • used to vary the intensity and size of the cone of light • Stage: The flat platform where you place your slides. Stage clips hold the slides in place. • Course Focus: large, round knob on the side of the microscope used for focusing the specimen • Fine Focus: small, round knob on the side of the microscope used to fine-tune the focus of your specimen after using the coarse adjustment knob How to Focus Your Microscope: • start with the lowest power objective lens • looking from the side, crank the lens down as close to the specimen as possible without touching it • look through the eyepiece lens and focus upward only until the image is sharp 1 µm= .000001m • Or one millionth of a meter • µ= micro- Microscopic Measurement 800 µm • Estimate the size of this paramecium 10x 800/3= 267 µm Field of view 600 µm Estimate the size of this Red blood cell 600/4= 150 µm Field of view 100x