Download Parts and Processes of a Microscope_1

Parts & Processes of
a Microscope
• Structures of a Microscope
• Functions of a Microscope
• How Microscopes Work
The Big Idea?
What are the parts of a “Compound
Microscope”
&
How do “Compound Microscopes” uses
lenses to magnify objects
Student Handout
•
Follow along with your
handout and fill in the
questions as we work
through the material
•
Green check marks will clue
you into when you should be
getting that info down on
your handout
History of the Microscope
A man named Leeuwenhoek was
the first to experiment with his own
microscope in the 1600’s
He looked at pond water, blood,
and plaque from his teeth
His discoveries shocked the
scientific world and people were
opened up to a whole new world…
microbiology
What Does It Do?
The microscope is designed to
collect and gather light from
small objects and enhance the
image for us to see
There is a limitation to the
microscopes capability, what
is that limitation?
What’s the Limitation
Some objects are just too small to reflect enough light for the
microscope to catch and create an image out of… they don’t
have the relevant surface area like larger objects to reflect
enough light for our eyes to detect
• This is why we can’t see many small micro organisms with
conventional light microscopes… there just isn’t enough light
•
•
So what can we do
if we want to see
extremely small
items?
Electron Microscopes
•
We can use electron
microscopes to magnify up
to 300000 x as compared to
a conventional microscope
that might magnify up to
500 x or 800 x
•
Unfortunately what ever
we are looking at has to be
dead!
How do they work?
•
Today’s Microscopes
Most of today’s
microscopes, including
the microscopes in this
room, have a light
underneath that is
designed to shine more
light on to smaller
objects in attempts to
allow us to see the
image
In Your textbooks!
•
Open to page 103 – 107
in the “Science Focus”
textbook and follow
along as we go through
some of the material on
magnification
•
Once we have read over
the information, you
are responsible for
filling out the back side
of your handout
•
Pages 98 – 101
in the “Science in
Action 8”
Textbook could
also be helpful
The Flip Side
•
Take sometime to fill out the flip side
of that sheet and then double check
your answers with a neighbor… will
be reviewing it in about 5 minutes
Note that in your text book they call
part 1 the eye piece… this is incorrect
for our purposes
• Call that piece the Ocular Lens
• Also, the bottom is called the Base
•
Ocular Lens
Eye Tube
Nose Piece
Arm
Objective Lens
Stage
Stage Clips
Coarse Adjust
Diaphragm
Fine Adjust
Lamp
Base
Compound Microscopes
•
Compound microscopes use two lenses in series to magnify an
image… they compound one and other, hence the term
“compound microscope”
•
The two lenses are the OBJECTIVE LENS and the OCULAR LENS
In order to calculate the total magnification taking place on
the image… simply multiply the magnification power of both
lenses together
•
OCULAR POWER x OBJECTIVE POWER = TOTAL MAGNIFICATION
Calculated Magnification
•
•
You now have a number (product) from the two lenses
That number represents how many times larger the image you
see in the microscope is than if you where to look at the object
with your naked eye
i.e. ocular lens is 5 x and the objective lens is 30 x
5 x 30 = 150 total magnification
no magnification
150 magnification
Practice Makes Perfect
Question 5
Ocular lens is 5 x and the Objective lens is 10 x
What is the total magnification of the image?
5 x 10 = 50
therefore the total magnification
is 50 and object appears to be 50
Who will do it on the board??
times larger than when seen with
the naked eye
Practice Makes Perfect
Question 5
Ocular lens is 5 x and the objective lens is 10 x
What is the total magnification of the image?
5 x 10 = 50
Therefore the total magnification is
50 and object appears to be 50 times
larger than when seen with the
naked eye
Practice Makes Perfect
•
Individually, try the next three examples on your
handout
•
We will go over them shortly but you should be able
to have this simple calculation down by the end of
this class
•
Volunteers will be needed to show us how you
figured out the magnification level on the BOARD!!!
Practice Makes Perfect
a)
High level objective lens
Ocular lens = 10
10 x 45 = 450 magnification
Objective lens = 45
b)
Low level objective lens
Ocular lens = 10
10 x 5 = 50 magnification
Objective lens = 5
c)
Medium level objective lens
Ocular lens = 10
10 x 12 = 120 magnification
Objective lens = 12
Study Up
•
Hang onto these sheets and
file them into your note book
in the proper order for this
unit
•
Save the sheets for study
purposes
•
There will be a QUIZ on what
we covered today as well as
the material we will cover in
the next couple classes so
STUDY UP