Download Lab 1 notes - Dr Magrann

CERRITOS COLLEGE: MICRO 200
LAB 1
I. ATTENDANCE: take attendance and check those on wait list. We will wait for another
hour, and those who are not here will be dropped. I can take 32 students max.
2. INTRODUCTIONS: lake an index card and write the following about yourself:
a.
b.
c.
d.
e.
f.
g.
h.
NAME
WHERE ARE YOU FROM
HOW FAR DO YOU V) RIVE TO GET HERE (minutes or miles)
WHAT TYPE OF WORK DO YOU DO? HOW MANY HOURS PER WEEK?
CAREER GOAL
LIST COLLEGE CHEM AND BlO CLASSES COMPLETED)
WHAT DID YOU DO OVER WINTER BREAK?
FAVORITE ACTIVITIES FOR ENJOYMENT?
Then hand your card to someone next to you. Your partner will introduce YOU to the class; this
is your first classroom presentation. Do not look at the card while you introduce your partner;
practice memorizing in formation.
3. STUDY TIPS: You will need to spend about 6-10 hours a week studying. Make yourself a
calendar of the due dates for reports, quizzes, exam dates, etc. Get yourself a separate
notebook for lecture and lab notes. Also, get a folder or binder to keep your lab data sheets.
For every lab, you read the lab manual and fill out the lab report (data sheet) in the hack ol the
manual. Keep these in a binder until the day of the midterm exam in lab, and turn them all in.
This batch will be worth 20 points for all of them. The second hatch of reports is due on the
day of the final lab exam and is also worth 20 points for all of them (total of 40 points). The
lab midterm and final are PowerPoint shows of the slides, not the actual microscopes.
4. SYLLABUS: Every Tuesday there is a quiz from the lecture material (No quiz on Tuesday
next week, and no lecture quizzes on a day of a lecture exam). Every Thursday there is a quiz
on the lab material from the previous week. The first lab quiz is not this ‘Thursday, but next
week, and will cover the material from today and this Thursday. Each quiz is 15 points. If you
miss a quiz you get a zero. Buy a package of quiz strips from the bookstore; there are about 15 in
each package. They are like little Scantron sheets.
Other things to purchase from the Bookstore: Goggles (can also get at home Depot, etc.
Should have guards on the tops and sides), glass slides (pack of 10), grease pencil—--aka China
Marker--(for marking bottom of plastic Petri dishes), lens paper (for cleaning microscope lenses),
Bibulous paper (for blotting slides), and three 882E Scantrons (one for lecture, two for lab—make
sure they don’t get wrinkled!).
Things to purchase from another store: A white lab coat needs to be purchased from a
uniform shop (one in Cerritos Mall, one on South and Palo Verde near Yoshinoya). Keep
them in the drawer you are assigned, and take them home every Thursday and wash them in
bleach and bring them back Tuesday. You will choose one of these drawers and put your
name on a piece of paper in the drawer; there is no need for a lock. You also need disposable
plastic or latex gloves, small box of matches to light the Bunsen burner, scotch tape, and a
felt-tip pen (fine) to write on the scotch tape to use as a label on glassware.
5. ASEPTIC TECHNIQUE: Our lab’s microbes are Bio Safety Level Two (BS2). You can
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read about this in the lab manual. BS2 microbes are potentially pathogenic (cause disease) if
a person is inoculated with a large dose or if the person is immuno-compromised. They
require autoclaving (steam heat sterilization) and have to be handled by aseptic technique
(we will discuss that next week. BS3 microbes have to be handled with safety equipment
under the hood. BS4 microbes require a space suit type of gear. This room has negative
pressure, so when you open a door, air moves into the room. All the air is circulated every
eight minutes.
6. ATTENDANCE AGAIN AND LOTTERY
7. LAB SAFETY: Open-toed shoes are not recommended since a spill can cause skin irritation.
Put equipment back in tote box under the cabinet near the front doors. Before leaving, I need
to check that your area has been disinfected, left clean, and that the microscope has been put
away properly. If it is found not properly put away, you will receive a note indicating what
was wrong with it.
The lab counters must all be wiped down with disinfectant when you come in and when you
leave. You may throw the paper towels into the regular trash afterwards.
Dispose of cover-slips, but the glass slides will be cleaned and re-used. Most fires in this lab
are started from alcohol becoming ignited. Just get away from it, cover it, and let it burn out.
Remember, a lab coat can be taken off and used to put out a fire if someone’s hair catches
fire, etc.
There is no gum or water bottles allowed in a micro lab.
The biohazard bag is for any and all hazardous materials, including a toothpick you put in
your mouth, gloves, disposable Petri dishes, etc. Use the regular trash for everything else.
There is a cart for the glassware: flasks and tubes. Make sure all labels are removed, and all
grease marks are erased first.
If there is a spill, cover it with paper towels, saturate them with disinfectant for ten minutes,
then put those paper towels in the biohazard bucket along with your gloves.
First aid kit is inside instructor’s cabinet. Campus police emergency: 911.
8. 15 MINUTE BREAK
9. MICROSCOPE USE: The arm should face you as you lift it up. Hold with one hand under
base, gently set on desk near edge, and then turn the arm away from you. Fold up dust cover
and put it in the drawer. Here are some booklets to help you identify the parts of a
microscope that are listed in this handout. Return the booklets at the end of lab.
10. PARTS OF A MICROSCOPE: Find the substage adjustment knob (left side, under stage).
What happens when you turn it? It raises and lowers the condenser. When you are done with
the microscope, leave the condenser in the highest position; this is called racking up the
condenser. Everyone point to this knob. The ocular is the eyepiece. It magnifies ten times and
focuses the image on the retina. There are two oculars. Do not touch your eyelashes to them
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or they will get oil on them. To clean, squirt alcohol onto lens paper and wipe, then wipe
with dry lens paper.
The left ocular has a diopter adjustment ring (knurled knob with ridges), with plusses,
minuses, and a zero on it. What happens when you move it? It moves the left ocular up and
down. The purpose of this is to allow the left eye to be focused independently of the right eye
(more details on this next lab). The coarse adjustment knob is for the right eye focus. If you
still see two images, you have a convergence problem and you’ll need to keep one eye
closed. Everyone has one dominant eye. Whichever eye is dominant on you (details next
lab), you place the ocular with the ruler (ocular micrometer, used to take measurements) on
that side when you need to use it. The other ocular has a pointer in it; keep this on the
dominant eye when you need to use the pointer. Between the oculars is a disc with numbers
on it. This determines the interpupillary distance in mm (distance between your pupils).
The revolving nosepiece holds the objectives. Practice turning it; listen and feel for the
objective locking into place. You need to know the following about the four objectives: The
scanning (red ring) objective is the smallest, and magnifies 4x. Since the ocular is 1 Ox, the
total magnification is 40x. The other number on the objective is the NA number; this
objective’s NA is 0.10. The low power objective is 10x, total mag = 100x, and NA is 0.25. The
high dry objective is 40x, total mag = 400x, and NA is 0.65. The oil immersion objective is
l00x, total mag = 1000x, and NA is 1.25.
NA stands for numerical aperture. Before the next lab, look up the following in your lab
manual: What does the numerical aperture mean? How do we calculate it? What’s the
relationship between the NA and the resolving power?
Focusing: Two knobs, coarse and fine adjustment. Fine adjustment is smaller and concentric
to the coarse adjustment knob. The coarse knob moves the stage a lot, and the fine knob
moves it a little. Changing the distance between the stage and the objectives to focus is called
the “working distance”. Always start with the scanning objective, since it is the only one that
can’t hit the stage and break the lens and the slide. Then make sure the condenser is racked
up. Then rack up the coarse knob so the stage is all the way up. Look at the slide, then lower
the stage with the coarse knob until it comes into focus. Only after that can you switch to the
next power up (yellow low power). To focus from now on, ONLY use the fine adjustment
knob.
PARFOCAL: This term refers to the factory adjustment which means that once you are
focused with the scanning objective, you are focused with all of the objectives (except for
fine adjustment for minor corrections). If you lose focus, always go back to the scanning
objective.
Inside the condenser is a lever: the iris diaphragm lever. This opens and closes like the iris in
your eye (pupil) to regulate the amount of light allowed in. The condenser takes light from
the lamp and makes the rays into a point on the slide. The iris does the following four things:
a. Regulates light intensity
b. Contrast: (when iris is open, the contrast decreases)
c. Depth of field (when iris is open, only the foreground is in focus. When the iris is
closed, the depth of field increases and everything is in focus.
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d. Resolution (sharpness of image). Resolution is best when iris is open all the way.
11. STORING THE MICROSCOPE: The arm should face your body, the dust cover in
place, the AC (power) cord is stored under the scope in the drawer, not wrapped around
it. The condenser should be racked up. The toggle switch for power should be off (it is
located in the front or side). The voltage regulator should be turned to zero or the lowest
setting. It is located on the side near the base or below the power switch. The stage
should be racked down by using the coarse adjustment knob (next to the arm). DO NOT
LOCK THE COARSE ADJUSTMENT KNOB by moving the thin lever on the inside of
the coarse adjustment knob. The scanning objective should be in place. Clean off the oil
and other debris; wipe the ocular lens with lens paper only.
BE ABLE TO MATCH THE PARTS OF A MICROSCOPE TO A PHOTO OF A
MICROSCOPE FOR THE EXAM.
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