LIGHT MICROSCOPE Care of Microscope Carry the microscope

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LIGHT MICROSCOPE

LIGHT MICROSCOPE

Care of Microscope Ø Carry the microscope holding the arm and support the base

Care of Microscope Ø Carry the microscope holding the arm and support the base with your other hand Ø Never touch lenses with your fingers Ø Never lower course adjustment knob when looking through the eyepiece lens Ø Always focus first with low power Ø Do not use course adjustment knob with high power objective lens in place Ø Stored to microscope covered

CELLS VARY IN SIZE Bacteria is approximately 0. 5 to 2. 0 μm Sciatic

CELLS VARY IN SIZE Bacteria is approximately 0. 5 to 2. 0 μm Sciatic nerve cell (nerve running down your leg from sciatic region of your back to your toes) can be as large as 1 meter Ø Diameter of an RBC = 7. 5μm Ø Ø

Magnification Ø enlargement of an image brought about by lenses (multiply eyepiece by objective)

Magnification Ø enlargement of an image brought about by lenses (multiply eyepiece by objective)

Calculating Total Magnification Eyepiece x multiplied by objective lens x Eyepiece Ø Scanning Ø

Calculating Total Magnification Eyepiece x multiplied by objective lens x Eyepiece Ø Scanning Ø Low Ø High Ø Oil = 10 x = 4 x = 10 x = 43 x = 97 x = 100 x Total magnification Ø 10 x 4 = 40 Ø 10 x 10 = 100 Ø 10 x 40 = 400 or Ø 10 x 43 = 430 Ø 10 x 97 = 970 or Ø 10 x 100 = 1000 Ø

Focusing Microscope Clean the microscope with lens tissue 2 Start on the shortest objective

Focusing Microscope Clean the microscope with lens tissue 2 Start on the shortest objective lens 3 Turn light down and center slide over light 4 Bring objective lens and slide together until they stop 5 Use coarse adjustment knob with low power objective lens to locate object 6 Turn to high power objective lens refocus with fine adjustment knob 7 Adjust light using diaphragm at each step as needed 1

Estimate the size of a cell Ø Light microscope measurements are in micrometers/microns (μm).

Estimate the size of a cell Ø Light microscope measurements are in micrometers/microns (μm). Ø There are 1, 000 μm in one millimeter, or mm.

Estimate the size of an object The low power field of view is about

Estimate the size of an object The low power field of view is about 4500 μm Ø How many stars would it take to cover the diameter of the field of view? Ø Seven stars would do it. Ø Divide seven into 4500 μm Ø The star is about 630 μm Ø an answer between 560 + 640 μm is reasonable Ø

Estimate the size of an object Ø The low power field of view is

Estimate the size of an object Ø The low power field of view is about 1700 μm How many wood chips would it take to cover the diameter of the field of view? Ø Four chips. Ø Divide four into 1700 μm Ø Ø The chip is about 425 μm

2. Electron microscope Ø Uses a stream of electrons instead of light to see

2. Electron microscope Ø Uses a stream of electrons instead of light to see images which are magnified more than with a light microscope.