Transcript Microscope
Introduction to the Microscope Care Parts Focusing Why Microscopes? • Why do we need microscopes? – To “see” what we can’t see with the naked eye. – Here are a few examples…. HIV (red) on a white blood cell (green) HIV is short for: Human Immunodeficiency Virus It is the virus that causes AIDS. There are dozens attacking this human white blood cell. Seeds (yellow) on the surface of a strawberry (red) E. Coli (brown) and viruses (blue) attacking •E. Coli is a kind of bacteria that can make us sick, but also lives in our stomach. •Bacteria are singlecelled organisms. •Viruses are not considered alive, and are NOT made of cells. Salt (left) and pepper (right) Protozoan •Protozoans are single-celled organisms found usually in water (most do not live in drinking water). •Malaria is caused by a protozoan. Human eyelashes (green) and skin •Notice how flaky the human skin is. It is constantly flaking off (sloughing) and being replaced from below. Blood clot crystals (scabs!) These crystals are only one component of a blood clot. Bee stinger Needle and thread • Magnification – making the object bigger • Resolution – how clearly you can see the object • http://brunelleschi.imss.fi.it/esplora/micros copio/dswmedia/simula/esimula1.html Light because we use light to see the images Compound because it uses two lenses to view a specimen. Can magnify up to 1,000,000x, as opposed to 1000x for light microscopes. Expensive! Specimens have to be dead (in a vacuum) Black and white images only Light vs. Electron Light vs. Electron Light vs. Electron Body Tube Revolving Nosepiece Objective Lenses Stage Clips Diaphragm Light Eyepiece or Ocular Lens Arm Stage Coarse Focus Fine Focus Base Body Tube Holds eyepiece Revolving Nosepiece Rotates and holds objective lenses Objective Lenses Eyepiece or Ocular Lens Where you look to see image – magnifies 10x Arm Used to carry microscope Low 4x, Medium 10x, High 40x Stage Stage Clips Where slide is placed for viewing Diaphragm For low power lens – always start here! Hold slide in place Controls amount of light Light Coarse Focus Fine Focus Fine tuning for higher power lenses Makes specimen easier to see Base Supports the microscope • Always carry with 2 hands, one on the arm and the other on the base • Only use lens paper for cleaning and don’t touch the lenses to anything (including your finger.) • Always store covered • Don’t let cords hang where the microscope could be pulled off the table • When finished, wrap cord around base • Ocular lens times the objective lens • If the ocular lens is 10x and the objective lens is 5x, the total magnification would be: 50! • Our ocular lens magnifies 10x. Our objective lenses are 4x, 10x, and 40x. • That means we can magnify 40x, 100x, and 400x • Place a slide on the microscope • Use stage clips only when you are sure you don’t want to move the slide around • Click nosepiece to the lowest (shortest lens) setting • Start with the objective closest to the specimen • Use the coarse focus to move objective AWAY from specimen • Have slide focused on low power first • Click the nosepiece to the next biggest objective lens • Do NOT use the coarse focusing knob • Use the fine focus knob • Do NOT force any knobs • They should all move easily • Do NOT turn the fine focus more than a full turn • Start over on low power if you can’t see specimen Onion Cells Cheek Cells Image 1 Image 2 Image 1 Image 2 Mosquito Image 1 Mosquito Stapled Paper Image 2 Image 3 Image 4 Black Widow Spider Claw Image 3 Image 4 Black Widow Spider Claw Image 3 Mascara Brush Image 4