Simple to Complex – Life’s Levels of Organization Our journey begins here.

Introduction to the Microscope Types Care Parts Focusing 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.

Stereoscope This microscope allows for binocular (two eyes) viewing of larger specimens.

Simple Microscope vs. Compound Light Microscope Which kind do we use? Lets light pass through an object and then through two or more lenses. Similar to a magnifying glass and has only one lense.

Stereoscope & Light Microscopes

Light Microscope light as source of illumination glass lenses limited resolution (loses resolving power at magnifications above 2000X)

Florescent Stained Cell –shows the skeleton (green) and Comparison of Microscopic Techniques for Visualizing a Living, Unstained Cell Florescent Stained Cell –shows the skeleton (green) and nucleus (purple) of the cell, etc. Bright field Phase-contrast

Higher Resolution Is Achieved by Viewing Sections of Fixed, Stained, and Embedded Samples A microtome cutting sections of an embedded sample.

What can you see with a microscope?

Electron Microscope Uses a magnetic field to bend beams of electrons; The two types are: Scanning and Transmission Uses a magnetic field to bend beams of electrons; greater magnification & resolving power than light microscope

Electron Microscopy A wavelength of electron beam is much shorter than light, resulting in much higher resolution

Scanning Electron Microscope (SEM) Allow scientists to view a universe too small to be seen with a light microscope. SEMs scan the surface of a specimen to magnify 3-D objects up to 150,000x Invented in 1965, see the 3-D surface of a specimen.

Scanning Electron Microscopy (SEM) Visualizes Surface Features

Specimen Preparation Specimens are coated with metals to deflect electrons from a beam scanned across the sample.

SEM of Stereocilia Projecting from a Cochlear (inner ear) Hair Cell

SEM Photos!

Transmission Electron Microscope (TEM) Electrons are passed through very thin specimens to see what is inside! Invented in1933 Magnification is 500,000x

A TEM of an Onion Root Tip Cell

Confocal Scanning Laser Microscope confocal microscopy and scanning probe microscopy have extremely high resolution can be used to observe individual atoms about 2,000,000x magnification

Confocal Scanning Laser Microscope More images!

Optical sections of a pollen grain Scanning confocal microscopy allows reconstructing a 3D image by stacking optical sections. Stacked sections

Scanning Tunneling Microscope The scanning tunneling microscope (STM) is a non-optical microscope that scans an electrical probe over a surface to be imaged to detect a weak electric current flowing between the tip and the surface. Can find the position of individual atoms and molecules on the surface

Scanning Tunneling Microscope Scanning tunneling microscope (STM) invented in 1981, is widely used in both industrial & fundamental research to obtain atomic-scale images of metal surfaces. It provides a three-dimensional profile of the surface.

Light Compound Microscope

Microscope Parts Eyepiece Body Tube Revolving Nosepiece Arm Objective Lens Stage Stage Clips Coarse Focus 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. Diaphragm Fine Focus Light Base

Microscope Care Always carry with 2 hands. Only use lens paper for cleaning. Do not force knobs. Always store covered Keep objects clear of desk and cords. Teacher demonstrates how to hold the microscope, where the lens paper is located and how to use it. Students will be invited to turn the knobs and observe the stage as it moves up and down. Teacher will demonstrate how to store the microscope.

Using the Microscope Place the Slide on the Microscope Use Stage Clips Click Nosepiece to the lowest setting (shortest objective lens) Look into the Eyepiece Use the Coarse Adjustment Knob to focus first then use the fine knob. Total Magnification= Give students a slide from the “common things” set, each student will practice focusing and changing objectives. ocular (eyepiece) X objective lens

What Are Some Characteristics of Microscope Viewing? Low power High power Magnification Objective lens X Eyepiece lens Field of view Light intensity Depth of field *layers or levels penetrated 28 Less Greater 1/18/01 Larger Smaller Brighter Dimmer More Less

Tips on Good Drawings of Specimens 1. Use pencil - you can erase and shade areas. 2. All drawings should include clear and accurate labels (and be large enough to view details), with the specimen name (usually on slide) and magnification. 3. Labels should be written on the outside of the circle. The circle indicates the viewing field as seen through the eyepiece, specimens should be drawn to scale – i.e. if your specimen takes up the whole viewing field, make sure your drawing reflects that. All arrows should end with the point touching the object to be labeled! last does not exist in certain plant cells).

Tips on Good Drawings of Specimens 100 X 400 X

Using High Power Follow steps to focus using low power Click the nosepiece to the longest high objective Do NOT use the Coarse Focusing Knob Use the Fine Focus Knob to bring the slide Have students exchange slides so they can look at different things, walk them through using the high power objective to focus slides. Emphasize not using the coarse objective during this process, as it will crack the slides. What can you find on your slide?

Which is the most powerful kind of microscope?

Use this animation for slide show for light, optics: lenses color etc.