Aim: How have microscopes impacted science? DO NOW: Explain this cartoon in your own words
Microscopes Microscopy is the art of producing images for microscopic things that are not visible to the human eye.
Robert Hooke's microscope (1665)
The first useful microscope Microscopes Through Time The first useful microscope was developed in the Netherlands in the early 1600s
Types of Microscopes Compound Light Microscope Models found in most schools, uses compound lenses and light to magnify objects. The lenses bend or refract the light, which makes the object beneath them appear closer.
2. Stereoscope – this microscope allows for binocular (two eyes) viewing of larger specimens.
Parasite that causes disease in your liver! Polychaete worm (aquatic) Parasite that causes disease in your liver!
3. Scanning Electron Microscope – allow scientists to view a universe too small to be seen with a light microscope. SEMs do not use light waves; they use electrons
4. Transmission Electron Microscope also uses electrons, but instead of scanning the surface (as with SEM's) electrons are passed through very thin specimens.
an Electron microscopes! Living specimens can NOT be viewed under an Electron microscopes! WHY? Due to the powerful laser beam, anything living would die!
A mosquito An ant
Threaded needle Scales of a moth wing
Antarctic Mite
Stinger of a mosquito
Aim: How do the parts of the microscope assist science? DO NOW: Hand-out
Parts of a Compound light microscope
The structure of a cell nucleus would be seen in the greatest detail by use of a compound light microscope an ultracentrifuge a dissecting microscope an electron microscope
Which is the correct sequence of historical developments leading to our present knowledge of cells? electron microscope – cell theory – compound light microscope compound light microscope – cell theory – electron microscope cell theory – electron microscope – compound light microscope electron microscope – compound light microscope – cell theory
Eyepiece/ ocular Bodytube arm stage base nosepiece Stage clips Objective lens Objective lens stage Objective lens Stage clips Coarse adj.knob Diaphragm Fine adj. knob Light source base
Eyepiece (Ocular lens): magnifies the image 10x
& Objectives (4x, 10x & 40x magnification) Stage Clips & Objectives (4x, 10x & 40x magnification)
Objective lens Attached to the nosepiece Usually three magnifications Examples: 4X, 10X, 40X Referred to as low and high powers
Low power objective = used to locate the specimen on the slide Larger field of view (See more of the slide, but less details) High power objective = More magnification Smaller field of view but more details
Deer Tick 41X Magnification
Deer Tick 657X Magnification
Diaphragm Used to adjust the amount of light entering the scope Located beneath the stage Diaphragm
Coarse (big) and Fine (small) adjustment knobs
ARM
TO CARRY THE MICROSCOPE!!! Remember!! ALWAYS USE TWO HANDS TO CARRY THE MICROSCOPE!!!
1.) Diaphragm
2. 3.
4. 5.
5.
Which structure is best observed using a compound light microscope? a cell a virus a DNA sequence the inner surface of a mitochondrion
After switching from the high-power to the low-power objective lens of a compound light microscope, the area of the low-power field will appear larger and brighter smaller and brighter larger and darker smaller and darker
Total Magnification Is numeric value that quantifies how much a specimen has been magnified. EX. 450X , 20X , 100X
Is calculated by multiplying the eyepiece power (usually 10x) by the objective lens in place.
What is the lowest possible magnification that can be obtained using the microscope shown? 20x 200x 40x 800x
Total magnification: Ocular X Objective = total (eyepiece) magnification Ex.) Objective lens Total magnification 4x 10x 43x
When viewed with a compound light microscope under low power, the letter "p" will appear as q p d b
How have microscopes impacted science? THE END