Microscope Flashcards
How did the invention of the microscope help scientists?
Allowed scientists to understand the building blocks of all living things
Robert Hooke
Assembled the first microscope and used it to examine a thin slice of cork
He saw many empty chambers and called them “cells”
Who was the first to observe living cells?
Antoni van Leeuwenhoek
Spontaneous generation
The idea that life could emerge from non living matter was accepted in the 19th century
Louis pasteur
Disproved the theory of spontaneous generation
Cell theory
- All living things are made up of one or more cells
- Cells are the smallest unit of life
The compound light microscope
Light passes through the specimen
Lenses enlarge or magnify the image
Micrometres
Used to measure very tiny objects
The symbol for micromètres is an upside down h
1mm=1000microm
1m=1 000 000 microm
The electron microscope
Has a higher resolving power than the light microscope
Uses a beam of electrons
See smaller objects and magnify up to 100 000x
Reveals diverse parts in the cell
Transmission electron microscope
Useful for exploring internal structure of a cell
Scanning electron microscope
Used to study the detailed architecture of the surface of the cell
Parts of the microscope
Ocular lens
Nose piece
Objective lens
Stage
Condenser
Light source
Base
Tube
Arm
Coarse focus
Fine focus
Objective lens
A set of 3 lenses magnifying the object at either 4x, 10x or 40x
Light source
Provides light
Revolving nose piece
Rotates to switch between objective lenses
Ocular lens
The part you look through, it’s lens magnifies at 10x
Arm
Connects the base with the tube
Coarse adjustment knob
Moves the stage in large movements (only use in low power)
Fine adjustment knob
Brings object into focus Using small movements (use under medium or high power)
Tube
Holds the eyepiece and lenses at a proper working distance from one another
Stage
Has the microscope slide stage clips to hold the slide in position
Diaphragm
Controls the amount of light reaching the object being viewed
Magnification
An increase in the apparent size of the specimen
To calculate magnification of microscope is ocular lens x objective lens
To calculate magnification of image is drawing size divided by actual size
Resolving power
The ability of an optical instrument to show 2 objects as separate
Explain the magnification of eyepiece and ocular lens and total
Eyepiece is all 10x magnification
Objective at low is 4x at medium is 10x at high is 40x
Total is at low 40x at medium 100x and at high 400x
Field of view
The diameter of the circular region of the slide visible under the microscope
What are the F.O.V at low high and medium power?
Low is 4000 micrometers
Medium is 1600 micrometers
High is 400 micrometers
How do you determine the actual size of a specimen?
- Determine the F.O.V based on the magnification setting being used
- Count the number of times the object fits in the F.O.V
- F.O.V divided by how many fits
How do magnification and F.O.V work together?
The higher the magnification the smaller the F.O.V
See less of the specimen but in higher detail
