‘Scopes & Scientists Review Students will have their microscopes out, for reference as we go through each of the steps. As an introduction, students will be asked what kinds of things they can do with this tool.

BIOGENESIS (life comes from life) ARISTOTLE ANTON van LEEUWENHOEK Special “vital” forces brought some living things into being, from nonliving material- “spontaneous generation.” Discovered microscopic life in pond water. “Animalcules”- tiny animals FRANCESCO REDI BIOGENESIS (life comes from life) Experiment: covered jars of meat vs. uncovered jars of meat. Results supported his hypothesis, maggots came from flies.

NEEDham = NEEDed to fix his experiment JOHN NEEDHAM NEEDham = NEEDed to fix his experiment Tried to prove spontaneous generation. Flaw with his experiment: the flask was not sealed and was exposed to the air. LAZZARO SPALLANZANI Boiled flasks of gravy to kill life, sealed one jar, left other jar open. Open jar had living microorganisms, sealed jar did not. Concluded that gravy did not produce life, organisms entered through the air.

spontaneous generation was incorrect. LOUIS PASTEUR Designed a flask that had a long curved neck open to air, but microorganisms could not travel through neck to the flask. Once neck of flask was broken, broth filled with microorganisms. Showed living things came from living things; spontaneous generation was incorrect.

Light Microscope Stereoscope Types of Microscopes Light Microscope  Uses compound lenses to magnify objects. The lenses bend or refract light to make the object beneath them appear closer. Stereoscope  This microscope allows for binocular (two eyes) viewing of larger (or thicker) specimens. Creates a 3D view of specimen

Scanning Electron Microscope (SEM) SEM creates a 3D view of specimen by scanning the surface, but cannot view living specimens (process kills them) SEM = “surface/scanning” Transmission Electron Microscope (TEM) Also uses electrons, but instead of scanning the surface (as with SEMs) electrons are passed through very thin specimens. TEM = “thin/through”

What kind of microscope is this? Compound Light Microscope This diagram is different than the one you need to label in your packet. Look at where the line is pointing to before you label it in your review packet! Eyepiece Body Tube Revolving Nosepiece Arm Objective Lens Red: Scanning Yellow: Low Blue: High Stage Stage Clips Coarse Adjustment Knob (BIG one) Diaphragm This is the exact version of the microscope used in class. Students will be identifying the parts on the microscopes at their desks as we go along and what their functions are. Fine Adjustment Knob (small one) Light Base What kind of microscope is this? Compound Light Microscope