Petri Dish experiment

3. BRAINSTORMING
ACTION PLAN PREPARATION
GET TO KNOW
EACH OTHER

4. AGAR POWDER
PETRI DISH
TIMER
COTTON SWABS
MEASURING SPOONS
MICROWAVE
BEAKER
BOX
TAPE
ZIPLOCK BAG
FACE MASK
HOTWATER LAB GOWN
SAFETYGOGGLES
SURGICAL CAP
SURGICAL GLOVES
DISINFECTANTS

5. PETRI DISH EXPERIMENT IS
ABOUT GROWING OF BACTERIA IN
AN AGAR-FILLED PETRI DISH.

6. 1. Clean the materials

7. 2. Mix ½ teaspoon agar (about 1.2 grams) with ¼ cup (60 mL) of
hot water in a clean, microwave safe container and stir.

8. 3. Place the container in the microwave and bring to a
boil for three minutes to completely dissolve the agar. The
mixture should be clear with no particles floating around in
the solution. Allow the mixture to cool for 3 to 5 minutes
before moving on.

9. 4. Fill the bottom half (smaller half) of the Petri dish with the
warm agar solution and cover loosely with the top half of the petri
dish (it may be necessary to set the lid ajar to allow moisture to
escape). Label the petri dish while waiting for solution to cool and
harden.

10. 5. Roll a clean cotton swab in your sample area. Be sure to
wipe the end of the cotton swab all over the surface to be
tested and cover the entire end of the swab with invisible
bacteria.

11. 6. Lift the top off the Petri dish and LIGHTLY draw a squiggly
line in the agar with the end of the cotton swab.

12. 7. Cover the Petri dish with the top half and use a piece of paper
or tape to label the dish with the name of the item you tested. Be
careful that when you replace the top of the Petri dish, that there
is not excessive moisture.You can place the Petri dish upside
down if moisture would drop on your sample. After you have
completed the sample and labeled the dish, place your Petri dish
in a sealed Ziploc bag

13. BACTERIA DO GROW IN PETRI DISH BYTHE HELP OF
NUTRIENT AGAR. NUTRIENT AGAR IS A GENERAL
PURPOSE MEDIUM SUPPORTING GROWTH OF A
WIDE RANGE OF NON-FASTIDIOUS ORGANISMS. IT
TYPICALLY CONTAINS (MASS/VOLUME): 0.5%
PEPTONE -THIS PROVIDES ORGANIC NITROGEN AND
PROTEIN SOURCE SOTHAT MICRO-ORGANISMS CAN
GROW. 0.3% BEEF EXTRACT/YEAST EXTRACT -THE
WATER-SOLUBLE CONTENT OFTHESE CONTRIBUTE
VITAMINS, CARBOHYDRATES, NITROGEN AND SALTS
WHICH SERVES AS FOOD FOR GROWING BACTERIA.

15. WANAWAN’S PETRI DISH
MOUTH SWAB SAMPLE
DAYS OF
OBSERVATION
BEFORE
DISINFECTANT
AFTER
DISINFECTANT RESULT/EVALUATION
FIRST DAY
(WED,
SEPT 15,
2 PM)
Before: few tiny clear white spot occurred.Visibility of
Bacterial colony can be seen by naked eye.
After: few tiny circular and rhizoid colony of bacteria
occurred. Colony of bacteria spread upward.
SECOND DAY
(THU,
SEPT 16,
2 PM)
Before: colony of bacteria multiplied into numerous
circular white spot, one spot on the left has a rhizoid form
around it.
After: the rhizoid part of bacteria in day 1 spread out and
filamentous formed bacteria occurred.

16. THIRD DAY
(FRI,
SEPT 17,
2 PM)
Before: bacterial colony spread through out the entire
petri dish forming circular and rhizoid. Black particles
started occurring in some circular formed bacteria.
After: colony of mixed flat and circular creamy-
yellowish bacteria started to spread through out the
entire petri dish.
FOURTH DAY
(SAT,
SEPT 18,
2 PM)
Before: A bit similar to day 3 but few white spots turned
as one.
After: Some area of the colony becoming thin and
translucent. Few white spots turned as one.
FIFTH DAY
(SUN,
SEPT 19,
2 PM)
Before: No visible changes on count, only black
particles darken a bit.
After: Some area became totally translucent, smooth
and very thin.

17. DUCLAYAN’S PETRI DISH
CELLPHONE SWAB SAMPLE
DAYS OF
OBSERVATION BEFORE AFTER RESULT/EVALUATION
FIRST DAY
(WED,
SEPT 15,
2 PM)
The first day of my observation of my petri-dish reveals a
lot of bacteria thriving. There are a lot of bacteria in the
(before) image, as you can see.The bacteria colony
expanded out in a non-uniform shape, with white being
the most prevalent hue.The (after) picture depicts a
smaller bacterium.The colony is primarily small, and its
hues are mostly white.
SECOND DAY
(THU,
SEPT 16,
2 PM)
Before:The second day of my observation of my petri-dish
shows a lot bacterium. It has a many tiny colonies and the
bacterium was compact each other and have a bubble.
After: As you can see in the image, the bacteria and
colonies separate and spread.

18. THIRD DAY
(FRI,
SEPT 17,
2 PM)
Before: In the picture, the bacterium looks like a cotton,
they become visible, and it has a color yellow colony.
After:The (after) pictures shows lot of yellow colonies and
they become visible.
FOURTH DAY
(SAT,
SEPT 18,
2 PM)
Before:The fourth day of my observation reveals many
developing colonies. Bacterial colonies have a variety of
coloring, with white being the most prevalent and having an
irregular form.
After: As shown in the image, the colony expands in a non-
uniform way, with several yellow colonies.
FIFTH DAY
(SUN,
SEPT 19,
2 PM)
Before:The bacteria continue to develop and become more
apparent, as shown in the image, where the white colonies
compress each other, and the yellow colonies are in the
midst of the white colonies. It appears that white is the
most common color.
After:Yellow is the most abundant hue in the image, and
they also compact each other.The colonies are mainly small,
but they become increasingly noticeable as time goes on.

19. SALIDA’S PETRI DISH
FLOOR SWAB SAMPLE
DAYS OF
OBSERVATION BEFORE AFTER RESULT/EVALUATION
FIRST DAY
(WED,
SEPT 15,
2 PM)
Before: shows a lot of growing colonies of bacteria.The
size of the colonies is tiny and irregular in shape and it
spreads out in a non-uniform pattern.The pigmentation
is mostly white or creamy white that are not yet fully
visible.
After: shows a lesser colony.The colonies are mostly
white and a creamy white.The colonies are tiny in size
and spreads out in a non-uniform pattern.
SECOND DAY
(THU,
SEPT 16,
2 PM)
Before: shows that the bacteria multiplied in number and
the colonies doubled in size.The pigmentation shows a
clearer hue of the white colonies and yellow colonies
started to develop.
After:The colonies also double in size.The pigmentation
is mostly white and circular in shape and the only yellow
colonies that is tiny in size developed and it is circular in
shape.

20. THIRD DAY
(FRI,
SEPT 17,
2 PM)
Before:The third day of my petri dish shows that the
pigmentation of the colonies is becoming brighter and visible
to the naked eye. Just like the pale yellow turned to a
brighter yellow that is more visible.
After:The after-petri dish started to develop more yellow
colonies that is tiny and not yet fully visible.
FOURTH DAY
(SAT,
SEPT 18,
2 PM)
Before: Fourth day observation shows that more bacteria are
developing into a yellow colony and their size is mostly tiny.
The white colonies expand, and it spreads out in a non-
uniform pattern.
After:The after-petri dish shows that the tiny yellow colonies
develop a clearer color of yellow.
FIFTH DAY
(SUN,
SEPT 19,
2 PM)
Before: Fifth day observation shows that the yellow colonies
doubled in size therefore there are more visible.The white
colonies continued to expand in a non-uniform pattern, and
they are mostly irregular in shape.
After:The after-petri dish shows that more bacteria of
colonies start developing into white and yellow colonies.The
colonies are mostly tiny and circular in shape.They spread
out in a non-uniform pattern.

21. CASTRO’S PETRI DISH
WATER DIPPER SWAB SAMPLE
DAYS OF
OBSERVATION BEFORE AFTER RESULT/EVALUATION
FIRST DAY
(WED,
SEPT 15,
2 PM)
In day 1, the result is very interesting because in BEFORE
(IMAGE) we can see that it have accumulated to form a
visible patches and the bacterial colonies appear white in
color and are fairly circular that are spread directly into
nutrient agar.The right image which is the AFTER
(IMAGE) we can only see a few bacterial colonies that
have formed in circular shapes on to nutrient AGAR.
SECOND DAY
(THU,
SEPT 16,
2 PM)
In days 2, there are numerous visible bacterial
colonies that appear in white color and are small
circular shape spread directly into nutrient agar in
our BEFORE (IMAGE) while in the AFTER (IMAGE)
we can see that a lot of growth bacterial colonies
were formedThan in DAY 1. In addition, there are
yellow in column and translucent circular in shape
bacterial colonies are formed.

22. THIRD DAY
(FRI,
SEPT 17,
2 PM)
In DAY 3, as can be seen in the BEFORE (IMAGE) there are
plenty of bacterial colonies were formed than day 2 and are
spread in small circular shape in white color. Nevertheless, in
AFTER (IMAGE)we can see that a black and yellow
translucent bacterial colonies were formed directly onto the
nutrient agar.
FOURTH
DAY
(SAT,
SEPT 18,
2 PM)
In day 4, the number of bacterial colonies are still rising, the
white small different shapes were prominent in that are
formed in the before image. Whereas in the growth of the
bacterial colonies gets higher in our AFTER (IMAGE).The
small circular shape are gets darker in color than the third
day and the yellow and black color circular shapes bacterial
colonies got bigger and darker.
FIFTH DAY
(SUN,
SEPT 19,
2 PM)
In Day 5, we can see that the growth of the translucent with
small different shapes of bacterias are getting higher in the
BEFORE petri dish (IMAGE) while in AFTER petri dish
(IMAGE) the small shapes of the translucent bacterias
colonies are getting higher. We can see also that the white,
black and yellow big shape bacterial colonies are still getting
bigger and darker.