MICROSCOPES ANTON VAN LEEUWENHOEK found that by placing
MICROSCOPES
ANTON VAN LEEUWENHOEK • found that by placing glass lenses (lenses refract light) at certain distances from each other, he could enlarge objects in his field of vision • Invented the 1 st microscope (light microscope)
Leeuwenhoek developed what is called a simple light microscope since it had only one lens. We mostly use compound light microscopes since they have more than one lens.
LIGHT MICROSCOPES Compound Light Microscope Simple light microscope • Contains only one lens • Contains more than one lens
TWO IMPORTANT MICROSCOPY TERMS • Magnification • Resolving Power
IMPORTANT MICROSCOPY TERMS Magnification Resolving Power • the comparison of the real size of a specimen with that of the one viewed under the • a. k. a. resolution • refers to the clarity of the specimen viewed under the scope Image of pollen grain with good resolution (left) and poor resolution (right)
PARTS OF A COMPOUND LIGHT MICROSCOPE
COARSE FOCUS ADJUSTMENT KNOB • Focuses the image under low power • usually the bigger knob
FINE FOCUS ADJUSTMENT KNOB • Sharpens the image under all powers • usually the smaller knob Fine Adjustment Knob
ARM • Supports the body tube and is used to carry the microscope Arm
BODY TUBE • Connects the eyepiece to the nosepiece • usually moves during focusing Body Tube
EYEPIECE • The lens you look through • Usually at 10 X magnification Eyepiece
NOSEPIECE • a. k. a. revolving nosepiece • holds all the objectives and it revolves Nosepiece
BASE • Supports the microscope and used for carrying the microscope Base
STAGE • Used to support the slide Stage
STAGE CLIPS • Used to hold the slide in place Stage Clips
DIAPHRAGM • Used to regulate the amount of light Diaphragm
LIGHT SOURCE • Provides light Light Source
LOW POWER OBJECTIVE • Has the lowest magnification and is the shortest objective Low power objective
MEDIUM POWER OBJECTIVE • increases the magnification Medium Power Objective
HIGH POWER OBJECTIVE • Provides the most magnification and is the longest objective. High Power Objective
CALCULATING MAGNIFICATION 1. Determine the magnification of the eyepiece (ocular lens) and each objective. 2. Multiply the magnification of the eyepiece with the magnification of the objective you are using.
EXAMPLE • Calculate the magnification of a microscope with an eyepiece magnification of 10 and objective magnification is 30. • Answer: 10 X 30 = 300
OBJECTIVES OF MICROSCOPE LAB • To learn the parts of the microscope. • To find specimens using low and high power. • To make a wet mount. • To view your own human cheek cells under the microscope.
MICROSCOPE CARE • Always carry with 2 hands • Only use lens paper for cleaning • Do not force knobs • Keep objects clear of desk and cords
Eyepiece Body Tube Revolving Nosepiece Objective Lens Stage Clips Diaphragm Light Arm Stage Coarse Focus Fine Focus Base
• Place the Slide on the Microscope • Use Stage Clips • Click Nosepiece to the lowest (shortest) setting • Look into the Eyepiece • Use the Coarse Focus
• Follow steps to focus using low power • Click the nosepiece to the longest objective • Do NOT use the Coarse Focusing Knob • Use the Fine Focus Knob to bring the slide What can you find on your slide?
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