Transcript Studnet Sample 7x

Counting Copious Colonies
How does disinfectant method affect amount of bacteria
still growing?
Carly Werner
Period 6
May 23, 2014
Discovery Project
Biology
Field Description
 Biology
 The study of living organisms.
 I chose this field of study because I had little
knowledge on the subject and wanted to learn
more.
Future Job Opportunity
 Microbiologist
 Research assistant
 A research assistant provides technological
support for a scientist to carry out his studies and
investigations.
 Relates to field because a research assistant
gathers knowledge on the field of microbiology
and prepares the microbiologist for his or her
own investigations.
Timeline
The discovery of
microorganisms was made
during the time period in
between 1665 through 1683.
Robert Hooke and Antoni van
Leewenhoek were the two
scientists who discovered the
existence of microorganisms.
This discovery changed the way
of preventing and killing
infectious disease.
In 1881, scientist Fanny
Hesse invented agar. Agar is
the substance that
microorganisms sit on when
in a sterile plate. This
invention helped scientists
get a more accurate view of
the structure and movement
of microorganisms.
Experimental Design Diagram
Title: How does disinfectant method affect amount of bacteria
still growing?
Hypothesis: If the disinfectant method is antibiotic soap and
hot water, then a very small amount of bacteria will still be
growing, because antibiotic soaps contain bacteria killing
substances.
Independent Variable: Disinfectant Method
Levels of
the IV:
Number
of Trials:
Antibiotic Hot
Soap and Water
Hot
Rinse
Water
2
2
Salt
Water
Soak
2
Hydroge
n
Peroxide
Solution
2
Background Research
 Due to the fact bacteria is grown specifically so
scientists can observe the individual colonies, the
growth patterns differ from the same bacteria that
grows in the wild.
 The pattern of bacterial growth depends on the
amount of change in the bacteria’s environment.
 Another factor that affects bacterial growth result
from nutrient agar concentration.
Procedure
Safety: Always wear gloves and never allow bacteria to touch
your skin directly.
Creating Sterile Plates
Creating Sterile Plates
No Method
Hot Water Method
Hot Water and Antibacterial Soap
Method
Salt Water Method
Hydrogen Peroxide Method
Data Table
How does disinfectant method affect amount of bacteria still growing?
Independent
Variable:
Dependant Variable: Amount of Bacteria Still Growing
(Bacterial Colonies)
Disinfectant
Method
Trial 1
Trial 2
Average
Hydrogen
Peroxide
5.0
3.0
4.0
Hot Water
22.0
6.0
14.0
Hot Water and
Antibacterial
Soap
13.0
14.0
13.5
Salt Water
10.0
7.0
8.5
No Method
11.0
7.0
9.0
Graph
How does disinfectant method affect amount of bacteria still growing?
16
14
12
10
Amount
Of Bacteria 8
Still Growing
(Bacterial 6
Colonies)
4
2
0
Salt Water
Hydrogen Peroxide
Hot Water
Disinfectant Method
Hot Water & Soap
No Method
Conclusion
 How does disinfectant method affect amount of
bacteria still growing?
 The hydrogen peroxide soak left the least amount of
bacteria still growing.
 4.0 bacterial colonies in average.
 Hydrogen peroxide contains bacterial killing substances.
 The hot water rinse, on average, left the most
bacteria growing.
 14.0 bacterial colonies
 The toothbrush was not able to rinse out long enough
under the hot water.
 There was a rip in the nutrient agar.
*restate hypothesis, CER, comparison
Application
-To improve the experiment, instead of soaking the
toothbrush in soap and hot water, the soap should be
rubbed on the toothbrush directly, then rinsed off with
hot water.
-This experiment relates to killing bacteria outside of a
lab. For example, when you cut a huge cut, you would
rub hydrogen peroxide on it to kill the harmful bacteria.
-A future experiment would be: How does temperature
affect bacterial growth?
Connect
Work Values
-Knowledge
-Learning and gaining information.
-Work value was met.
-Location
-Working somewhere that provides pleasure.
-Work value was not met.
-Adventure
-Coming across new and exciting things.
-Work value was not met.
*Elaborate