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pinkey what is on the kitchen table oh
it's my protest I'm hoping to find some
Euglena maybe some Paramecium
I took the sample from up I meant why is
it on the kitchen table oh I got
distracted I was gonna take some drops
and put it on a slide while I set up my
microscope yes well please get your
green water away from where we eat green
water
don't be ridiculous petunia there are
tons of protests in here we just have to
find them well you're out of luck
the protists that I'm looking for are
unicellular meaning they're made up of
one cell and generally you need a
microscope to see them never used one of
those you've never used a microscope
before no well you know what that means
I'm afraid of what that means we must
explore the world of microscopes
first of all let's focus on a few terms
that are important in order to
understand microscopes magnification is
one that's really what most people think
of when they think of a microscope and
we're gonna talk more about that in a
moment but another term that is
important is resolution basically are
you able to distinguish between two
objects this is important as otherwise
two objects could actually look like one
object because you can't distinguish
between them so for example if a
microscope had a resolution of 0.2
microns then that means two objects need
to be point two microns or more part in
order to see that they are two different
objects and not one if you want to
understand the physics of how resolution
works and how it's calculated we have a
great further reading suggestion in the
video details so let's talk about some
different types of microscopes that all
take into account this need for
magnification and resolution in order to
see specimens first light microscopes if
you're in a classroom this is likely
what you have and is its name would
suggest it uses light in order to see an
image bright field light microscopes
tend to be what people are most familiar
with typically producing a darker image
on a light background with a dark field
light microscope you have a piece that
blocks the light source called a light
stop the idea is that most light has
been blocked so the only light you see
is light
reflected or refracted from structures
within the specimen that you're looking
at so you tend to see light images on a
dark background there are many other
types of light microscopes too we have a
great link for further reading
suggestions to learn how each of these
work and some of these are fascinating
some rely on interference some rely on
using a laser but the thing to keep in
mind is there are certain times when one
of these types of light microscopes is
more ideal to use than another so light
microscopes use light in some form to
see a specimen but not all microscopes
are light microscopes for example what
if we want it to see a virus viruses are
generally very small typically much
smaller than the average bacterium how
can we increase magnification and
resolution abilities to see them that's
where electron microscopes come in
electron microscopes use electron beams
to visualize images transmission
electron microscopes tems tend to be the
most ideal for visualizing structures
within the specimen while scanning
electron microscopes SEMS tend to be
most ideal for visualizing the 3d
surface let's come back to the typical
microscope you might see in a classroom
which happens to be the one that I own a
bright field light microscope here is
our light source light passes through
this the condenser lens to focus the
light on the specimen the level of light
can be adjusted by the diaphragm our
specimen likely to be on a microscope
slide will be placed on the stage here
light will be reflected refracted or
absorbed by the specimen but we rely on
these lenses here at the objective lens
and the eyepiece lens to get our total
magnification
in fact this is often referred to as a
compound microscope because it has two
sets of lenses you can see that the
objective lenses are attached to this
revolving nosepiece which allows them to
be rotated so you can select a certain
one that you want to use with my
particular microscope I have three
objective lenses a scanning objective
lens that magnifies four times the
low-power objective lens that magnifies
ten times and the high power objective
lens which magnifies 40 times but don't
forget the eye
piece lens because that also magnifies
images and my particular eyepiece lens
magnifies ten times so let's say I used
the scanning objective lens I would
multiply that objective lens
magnification level by the eyepiece lens
magnification level so that my total
magnification is 40 times now you'll
also notice there's a lot of knobs here
let me introduce you to the knobs this
large knob here is known as the coarse
focus and then the smaller knob here is
known as the fine focus both of these
knobs raise or lower the stage which
helps of focusing the coarse focus knob
will move it more dramatically whereas
the fine focus knob will move it in
smaller increments these knobs the stage
knobs don't move the stage up and down
but rather from side-to-side instead it
helps you explore what's on the slide
itself but it isn't adjusting the focus
of it not all microscopes have those
stage knobs sometimes you have to move
the slide manually this is the
microscope arm and the base whenever you
pick it up you want to make sure you
have one hand underneath supporting the
base and the other hand holding the
microscope arm since it plugs in you
want to make sure there isn't water
around it so let's take a look at what's
in this water sample here I'm gonna do
something called a wet mount to prepare
my microscope slide I'm going to drop a
drop or two of my water sample onto the
slide using a disposable pipette it's
like a very fancy eye dropper kind of
I'm gonna put a cover slip on top
there's some techniques to doing a wet
mount to avoid air bubbles that you can
check out online air bubbles actually
can look kind of beautiful under the
microscope which can lead to great
disappointment when you find out they're
not some amazing microscopic organism
but rather just an air bubble something
I may or may not know by experience I'm
gonna put the slide on the stage I'm
going to use the stage clips here to
secure the slide light is on and I
already have the scanning objective lens
here ready to go which is good because I
want to find the specimen first I can
adjust the light level if I want but
just know that super bright doesn't
always mean the best image I can look
through the eyepiece and use the course
focus now
to move the stage up or down slightly to
focus patients you clean up I can also
fine-tune focus it with the fine focus
knob I can use the stage knobs to center
my image now that I found it with the
scanning objective lens I'm now going to
move up to the next magnification level
so remember total magnification would be
100 times since I'd already focused it
with the scanning objective lens it's
likely I only need to use the fine focus
knob to adjust the focus I could
continue to move up to the high power
objective lens which would give me a
total magnification of 400 times now
three additional tips about using
microscopes that I just want to mention
number one most microscope slides are
glass so they can break if dropped and
if using coverslips keep in mind they
are extremely easy to lose if not
careful number two always be aware of
where the slide is when you're moving
the stage up and down with the focus
knobs it's possible to move the stage
too close to the objective lens and
actually crushed the slide and number
three if it's hard to see your image
even when focusing you may need to clean
the lens but you need to do this by
wiping it with lens paper not regular
tissue when you're done with the
microscope make sure the slide is
removed turn off the light lower the
stage to its lowest position and return
the lowest objective lens over the stage
unplug it wrap up the power cord and if
you have a cover cover the microscope
before putting it away keep in mind
there are some techniques to better
visualize some specimens such as using
different stains or using immersion oil
at highest magnification to increase
resolution definitely something to
explore that this video doesn't go into
microscopes open up an entire world that
you can't see with the naked eye
microscopes can also complement what you
might be learning in life science
studying mitosis check out the cross
section of an onion root tip where lots
of mitosis happens studying plant
responses take a look at stomata from a
thin sample underneath a leaf studying
osmosis take a look at how aquatic plant
cells respond to different salt
concentrations endless possibilities to
explore endless curiosity
well that's it for the mucus sisters and
we remind you to stay curious
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