Transcript MICROSCOPES - Hudson City School District

MICROSCOPES
Compound Light

Parts of the Microscope
Compound Light
Uses
two lenses
–ocular
–objective
To
bend light
Resolving Power
 Being
able to
tell two
objects apart
 Measure of
“clarity”-how
clear it is
Resolving Power
 smallest
separation between
two object points that a given
lens (or mirror) can still show as
two distinct entities, not one

..
.
Pollen
Under 1000X LM
Over 1000 X SEM
MAGNIFICATION

Increase in the apparent size of
an object

MULTIPLY THE OCULAR LENS x THE
OBJECTIVE
– OCULAR 10x
– OBJECTIVE 40 x
– WHAT IS THE TOTAL MAGNIFICATION?
–400 x
How do they look different?

Leaf 4X
 Leaf
10 X
ADVANTAGES of LM:
 CAN
MAGNIFY UP TO
1000 x
 CAN VIEW LIVING THINGS
 Resolving power 200 nm or
0.2 µm
Disadvantages of LM
 Objects
must be thin or
transparent so light can go
through them

The image is inverted
Dissecting Light Microscope
 Image
is NOT inverted
 Usually 40 X is the limit
Pictures of LM microorganisms
Can be
stained
Microorganism Videos
You Tube 10
Microscopic
Critters
 Microscopic Life
of a Puddle in My
Back Yard
 You Tube Life in
a Drop of Pond
Water




You Tube Pond
Water Organisms
Protozoan
Feeding Frenzy
You Tube
Plankton Under a
Microscope
Videos

Microscopic World
Dissecting Scope Viewing
Light-colored stage
for dark specimens
and dark-colored
stage for light ones
Dissection Scope View of Insect Wing
ELECTRON MICROSCOPE

USE MAGNETS TO FOCUS A BEAM
OF ELECTRONS
–TEM (Transmission
Electron Microscope)
–SEM (Scanning Electron
Microscope)
SEM: Scanning Electron
Microscope Advantages
 Electron
beam scans the
surface
 Resolution 10 nm
 Magnifies 1,000,000 X’s
SEM Disadvantages
 Must
be in a vacuum (dead)
 Cannot see internal structures
SEM Images
house fly


and its mouth
Choose Critter and Change Image

Molecular Expressions Microscopy
Primer: Electron Microscopy Interactive
Java Tutorials - Virtual Scanning
Electron Microscopy
TEM Advantage
Can magnify 1000 X’s more than a light
microscope
(Uh…1000 X 1000 = 1,000,000 X’s )

Resolving power 0.2 nm
TEM Disadvantages
 Must
be in a vacuum (dead)
 Sample must be
VERY THIN (less
than 0.2 nm)
TEM Images
SPM-Scanning Probe
Scanning Probe Microscope
 Viewed ATOMS!!!!!!!!!!!

Does not need sample in a
vacuum
 Magnifies

10 million times
SPM Images (50 um X 1.4 um)

Steel Surface
SPM Images

DNA
FIRST TO VIEW ATOMS!!!
Comparing Bacteria


Light Microscope
SEM
H TEM
Label the parts
Ocular (eyepiece)
Body
tube
Revolving nosepiece
arm
Coarse adjustment
objectives
Stage clips
stage
Diaphragm lever
condenser
Fine adjustment
light
base
Always start with the lowest lens
 That
is, as you increase
magnification, the actual
field of view becomes
proportionally smaller.
 4OX
100X 400X
Use REVOLVING NOSEPIECE –
don’t grab lenses
Push slide to
back and control
with adustable
arm
Depth of Field = to the thickness of
the plane of focus
Viewing “F” with A Light
Microscope

Which is an “F” put in a compound light
and a dissection light microscope?
Field of View

What is the approximate width in mm?

In µm? (1 mm = 1000 µm)
Put edge of mm
marking on edge of
view
4
mm 4000 µm
What is the field of view of each
in mm? in µm?


2 mm x 1000 = 2000 µm
3 mm x 1000 = 3000 µm
Why use the letter “e?”
Do the math:
 one
millimeter (mm.) =
1,000 micrometers µm
 So
5.5 mm = ________ µm
 5500 µm

Convert each of the following to
micrometers (µm).

a)
3.5mm

b)
4.0mm

c)
1.5 cm

d)
0.5 cm

) 3.5mm(1000) = 3500µm

b) (4.0mm 1000) = 4000µm

c) 1.5 cm(10) = 15 mm(1000) =
15000µm

d) 0.5 cm(10) = 5mm(1000) =
5000µm
NOTE!!!!!!!!!!!!!!!!
 The
field diameter at high
power is proportional to the
ratio of the low to high power
objectives.
 If 40X is 4000 µm

400X is 400 µm
What if the view is so small, a
metric ruler cannot measure it?
High power field of diameter =
 Low power FD X low magnification
High power magnification
 EXAMPLE:
 4000 X 40
= 160,000 = 400 µm
400
400
Can also use to calculate oil
immersion FD, just divide by 1000.

FD = field diameter

Low power FD X low magnification
high power magnification
= high power FD
Use when
object is
between the
mm markers
Why do you need to know Field
Diameter?
 You
may wish
to estimate
the size of the
specimens
(e.g., cells)
you will see in
lab.
Field of View

What is the approximate size of this
cell?
In mm? 2
In um? 2000

If 5 fit across…

O.4 mm


400 µm
If the field of view in this question is
2 mm…
How long is
2
mm
one cell?
If the field of view in this question is
4 mm how long is one cell?
Field diameter______
How many can fit across
=
4000µm
3
= 1333 µm
4000µm
Wet Mount Making a wet mount animation
1. Add drop of water
3. Add cover slip
2. Place Specimen on
slide
4. Tap out bubbles
Making a Wet Mount Slide


Add drop of water
Add cover slip
Potato: no stain
Potato with
Iodine (cells are
octagonal shape with starch crystals as
blue black)

Onion

Uncooked, unstained

Onion with iodine
Elodea
Elodea: water vacuole shrinks or
pushes chloroplasts to outside

Salt Water
In Fresh Water
Cytoplasmic Streaming Video

You Tube cytoplasmic streaming video

Another Cytoplasmic Streaming Video
in Elodea