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Microscope skills

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Stereo microscope

Has two sets of lenses, including the eyepiece.

Used when a specimen is is opaque (light does not pass through it).

Usually lower power 10x to 20x

The observer sees the surface of the specimen being studied.

The specimen is placed in a container on the stage of the microscope

Compound microscope

Used when a specimen is translucent (some light passes thru it)

Usually higher power 10x to 300x

The observer sees all the way thru the specimen being studied.

Has more than two sets of lenses.

compound microscope

Has an eyepiece lens  (or ocular) and two or more sets of objective lenses

They sit on on a nosepiece that can revolve

The specimen is placed on the stage of this microscope.

Parts of the microscope

Label Microscope parts

 

 

 

 

 

  1. eyepiece (ocular) – where you look through to see the image

  2. body tube – Holds the eyepiece and connects it down to the objectives

  3. fine adjustment knob – Moves the body of the microscope up/down more slowly; fine control. Gets the specimen exactly focused. Only use after you first use the coarse adjustment knob.

  4. nosepiece – rotating piece at the bottom of the body tube. Lets us choose between several lenses (objectives.)

  5. high power objective — used for high power magnification (the longer objective lens)

  6. low power objective — used for low power magnification

  7. diaphragm – controls amount of light going through the specimen

  8. light/mirror – source of light, usually found near the base of the microscope.

  9. base – supports the microscope

  10. coarse adjustment knob — Moves body of the microscope up/down more quickly; Gets specimen approximately focused.

  11. arm – Holds main part of the microscope to the base.

  12. stage clips – hold the slide in place.

  13. inclination joint – used to tilt the microscope

Rules

  1. Always carry the microscope with two hands – one on the arm and one underneath the base of the microscope.
  2. Do not touch the lenses. If they are dirty, ask the teacher for special lens paper.
  3. If using a microscope with a mirror, do not use direct sunlight as the light source. Blindness can result. If using a microscope with a light, turn off light when not in use.
  4. Notify teacher if a slide or cover slip breaks. Do not handle broken glass.
  5. Always clean slides and microscope when finished. Store microscope set on the lowest power objective with the nosepiece turned down to its lowest position (using the coarse adjustment knob).  Cover microscope with dust cover and return it to storage as directed by your teacher.

How to use

  1. Begin focusing on the lowest possible power.   Center the specimen you are observing in the field of view before switching to a higher power.
  2. Move the objectives away from the specimen when focusing – so their is no collision between the objective being used and the slide/cover slip which may damage the objective lens.
  3. As you switch from low to high power, the field of view becomes darker.
    To deal with this the diaphragm needs to be opened to allow in more light.   (Frequently on low power the diaphragm needs to be partially closed as it is too bright.)
  4. As you switch from low to high power the field of view becomes smaller.

Images viewed under the light microscope are reversed (backward) and inverted (upside down).

images upside down and backwards microscope

Learning Standards

College Board Standards for College Success: Science

LSM-PE.2.1.2 Gather data, based on observations of cell functions made using a microscope or on cell descriptions obtained from print material, that can be used as evidence to support the claim that there are a variety of cell types.

LSM-PE.2.2.1 Describe, based on observations of cells made using a microscope and on information gathered from print and electronic resources, the internal structures (and the functions of these structures) of different cell types (e.g., amoeba, fungi, plant root, plant leaf, animal muscle, animal skin).

2006 Massachusetts Science and Technology/Engineering Curriculum Framework

Inquiry, Experimentation, and Design in the Classroom: SIS2. Design and conduct scientific investigations. Properly use instruments, equipment, and materials (e.g., scales, probeware, meter sticks, microscopes, computers) including set-up, calibration (if required), technique, maintenance, and storage.

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