Does covering mouths when coughing keep germs inside

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Abstract

In recent times influenza and other infectious disease have continued to populate and frighten the world. The CDC have deployed many attempts o help prevent these disease from spreading sporadically across the world. This is where I asked the question if facemasks, a form of protection against germs, would keep the germs inside of the mask. To begin to answer this question, I researched different types of facemasks and their properties. I also researched coughing and sneezing, in general, since these are the two major ways that people infect other people. I conducted an experiment from the use of bacterial cultures and tested different ways of prevention, facemasks, hands covering a mouth, and nothing covering the cough. The bacterial culture would provide an idea of which ways prevent germs effectively. After the experiment was conducted the colonies that grew in the agar medium, of the culture, would be identified and provide a conclusion towards the experiment. The results concluded that there was a mistake in sterilizing the agar medium; however, from the data collected the facemask seemed to have less bacterial growth from the beginning of the experiment. Since the agar medium was contaminated the experiment only proved that the method, used to obtain a bacterial culture, needs to be improved and modified.

Table of Contents

Title Page 1

Abstract 2

Table of Contents 3

Acknowledgements 4

Introduction 5

-Includes the research question, and how I came across the experiment

Background Information 5

-Includes research on certain types of facemasks and coughing/sneezing

Hypothesis 7

Methods and Development 7

Variables 9

Procedures 11

Raw Data 14

Data Analysis 21

Discussion 26

Conclusion and Evaluation 29

Bibliography 31

Acknowledgements

To begin, I would like to proudly thank my devoting advisor and Biology teacher, Mr. Earl Hockin, who has helped me every step of the way in completing this Extended Essay. The support I received in finishing this piece of work came from a number of people that are important in my life.

My parents have been with me through all the late nights and the work that I have put forth into this essay, they gave me the encouragement and strength to carry on throughout the hard times.

I would also like to give thanks to the Biology department at the Anglo-American School of Moscow, for allowing me to conduct my experiment with the proper equipment.

Research Question

To what extent does covering our mouths when coughing keep germs inside the confines of a surgical facemask?

Introduction

Doctors all over the world are required to wear facemasks when treating patients, especially with an open wound or surgery. Why would doctors wear these masks, over giving germs to people when in fact germs are everywhere? Doctors wear these masks to keep as many germs away from their patient as possible, if the wrong germs were to be present when a surgical procedure is occurring that patient may suffer from an infection.

Facemasks are also presented in the public, builders use it to keep small harmful particles out of their mouth and everyday people have began to wear facemasks from the recent H1N1, swine flu, epidemic of 2009-2010. The idea of this experiment arose from this recent outbreak of swine flu, I continually noticed more and more people wearing facemasks when in crowded public areas. Facemasks are exhibited in every part of the world, wherever there are hospitals and doctors there are facemask, which posed the question, do facemasks keep harmful germs away from people who where the mask?

Background Information

There are two main types of facemasks, surgical facemasks and respirators. Surgical are a loose piece of filtered cloth that loosely covers the mouth, they are use to mostly keep small droplets and germs from ones mouth away from other people. Respirators are a tightly fitted mask, used to keep very small particles from entering or exiting the person wearing the mask. Surgical masks and respirators are said not to keep a full protection from germs that cause illnesses, like the flu, which poses the question, how much protection do facemasks provide for us?

When wearing a facemask or respirator people believe that they are immune from the potential threats of illnesses, such as the flu, this is not true. Scientists are still unclear on if facemasks or respirators are beneficial or useless, this being said currently facemasks and respirators have not been fully proven to protect a person from certain germs. [1] Because facemask and respirators do not fully protect from germs, according to the CDC, this creates another question, how much do facemasks or respirators protect us from germs.

Most people do not wear facemasks every time they get a cold or illness, but use other ways to confine germs to themselves this includes covering their mouth, coughing in their elbow, or turning away from people to cough or sneeze. A cough, however, can travel up to 100 mph, which could potentially breakthrough the facemask. [2] 

When people go to the doctor, to find out if they have an infection of some sort, the doctor will take a sample that they can test from a culture. A culture determines whether not a person has a certain infection, the doctors determine this from what bacteria they see in the culture. Most cultures are taken from either a Petri dish or a test tube; the bacterium grows in a type of "goo" called a culture medium, in this experiment the culture will use agar medium. [3] Agar medium is used in this experiment due to its toughness against bacteria; agar is like gelatin but will not degrade when applied with bacteria. [4] 

When selecting my extended essay topic for biology I continually tried to come up with an experiment that involved some type of disease, my biology teacher ran an idea across me of the recent outbreak of swine flu, how people were afraid of catching this disease, so they wore facemasks.

Hypothesis

For this experiment, the surgical facemask will go against normal defenses a human uses to stop a cough, like covering the mouth using hands. If germs from a cough are transferred from a human into a Petri dish filled with bacteria-encouraging agar medium, then a human wearing a surgical facemask will stop most of the bacteria from contaminating the dish thus causing less bacterial growth and coughing directly in to the dish will present the most bacterial growth.

Methods and Development

When testing the hypothesis, I will conduct bacterial cultures of my cough using different methods to try and effectively prevent the cough from spreading germs. To perform this, I must hold a Petri dish close to my mouth when I cough, about 5 inches. To keep foreign bacterium from contaminating the Petri dish, the process should move quickly as possible; the agar in the Petri dishes need to have the least amount of time exposed to air. The agar medium must also be proved to be sterilized in a pre-experiment.

After the cultures have grown bacteria for 7 days, calculating the amount of bacterium will include counting each bacterium that grows in the Petri dishes by the naked eye. The control of the experiment will be the dish that I cough directly into, without anything to cover my mouth. The control will help compare the differences between my results and what is really happens when I cough into a facemask or into my hands.

When conducting my experiment, I will be collecting cultures in a clean laboratory, which provides the right equipment to conduct the experiment. I will be using a method of culturing that uses the agar medium and a warm environment, this method is widely used in the biology world. The culture will be placed in a controlled environment for a total of 7 days, at a temperature 25°C. A pressure cooker and a heat plate will sterilize the Petri dishes. This will help sterilize the agar medium and the Petri dishes. Sterilizing my supplies will help to ensure that no foreign germs will affect the results of my experience.

In my experiment, I will have three different ways to cover my cough, and five trials. The three ways of prevention include not covering mouth at all, covering mouth with my hands, and covering my mouth with a surgical facemask.

For this experiment, I expected to see a variety of different results in the bacterial growth; I mainly predict that hands will block a less significant amount of germs than the masks. I predict this because the masks were engineered to block germs from escaping and the body cannot keep all the germs from escaping.

When collecting my data there are three things, which I will be recording as, I conduct my experiment. First, I will count, by the naked eye, how many bacterium colonies grew, then I shall record how much space each colony takes up, and finally I will record any qualitative data that I observe. Calculating how much space each colony takes up will be performed by using a transparent graph paper to count the percentage each colony takes up.

Variables

Independent variable:

The independent variable for this experiment would be the methods for covering a cough

Dependent variable:

The dependent variable for this experiment would be the bacterium that grows in the cultures, since the independent variable will determine the amount of growth from the ways of prevention

Control Group:

The control of my experiment is directly coughing into the Petri dishes, since there is no prevention used to stop the germs.

Constants:

Period time of bacteria growth:

I will allow the agar medium sit for 7 days or 1week after I have conducted my experiment, to insure maximum bacterial growth

Type of Agar medium:

The agar medium used is from the products of Philip Harris

Room temperature around the Petri dishes:

25°C Room temperature

Room environment:

The Petri dishes will be kept in a dark closed cupboard for the time period of growth

Type of Petri dish:

The glassware product used was Pyrex with a ± 0.02 uncertainty

Person coughing into the Petri dishes:

I will be the only person coughing into the dishes so the results only come from my germs

Temperature of the pressure cooker:

The temperature cooker will reach to 100°C to sterilize the agar and the Petri dishes

Temperature of the heat plate:

the temperature of the hotplate would be 100°C

Clean Facemasks:

when coughing into a facemask, that facemask will be replaced to insure no build up of excess germs

Apparatus

Agar powder: Philip Harris© 1200mL of H20 and 23g of powder

Glass Mixing stick

Tefal© Kettle 1 liter

45 Petri dishes

Pressure Cooker: Land Life© 950mL of H20

1 Flask

Digital Scale

Heat Plate

Roll of Cotton

Pyrex® Glassware 1 liter Uncertainty ± 0.02mL

15 Surgical Facemasks

Thermometer

Sharpie©

Masking Tape

Procedures:

Pre-Experiment:

To ensure that the agar medium and the Petri dishes are sterile and have no germs already present, a pre-experiment needs to be conducted.

Procedure:

Sterilize the Petri dishes and the Agar medium (instructions below)

Pour the agar medium carefully into 15 Petri dishes

Let the dishes sit and dry for 7 days

After 7 days if any bacterial growth is present then the supplies are not sterile and the process needs to be completed before the experiment is conducted.

Sterilizing the Petri Dishes

Collect supplies: Petri dishes, pressure cooker, H2O for the agar medium, agar medium powder (Phillip Harris ©)

Fill the pressure cooker with about a mL of H20

Pull together dishes so they are sealed together (one on top and on bottom) and carefully place them in the preset pressure cooker, without lifting the dishes off each other.

Let the dishes cook for 15 minutes.

While waiting for the Petri dishes to cook, prepare the agar medium.

Once Petri dishes are done cooking, carefully take each one out at a single time without lifting them off each other.

Agar Medium

Collect the agar powder, H20, a digital scale, Pyrex 100mL glass, Tefal© kettle, heat plate, flask, and cotton

Weigh the right amount of agar powder on the digital scale

Heat up desired amount of H20 in the Tefal© water kettle, pour in a Pyrex 100mL glass

Slowly pour agar powder in the hot water, mixing while pouring.

After the agar is fully dissolved in the water, pour the solution into a flask.

Seal the flask with cotton making sure that air cannot flow through.

Let the solution sit until the medium becomes completely solid, approximately 1hour.

Heat the solid medium on the heat plate at 100°C until the medium is liquid (keep cotton in at this point)

Pouring Medium into the Dishes

After heating the agar medium align the sets of Petri dishes in 3 rows of 5.

Carefully lift the top of a Petri dish, try to keep the Petri dish as closed as possible, and quickly fill half of the dish with the liquid medium.

Continue for each of Petri dishes.

Let each dish dry until medium is solid again, approximately 20 minutes.

When the dishes are completely dried, start the experiment with the first row of five dishes. Open the top lid, place the dish 5 inches away from your face, and cough hardly twice into the dish.

Continue with the rest of the dishes in the first row.

In the second row, open the top of the first dish and place your hand over your mouth, cough twice into the dish and continue for the remaining dishes.

For the last row, place a surgical mask over your mouth, open the top lid of the first dish, and cough twice into the dish. Repeat for the final dishes, taking off and replacing the mask for each dish.

After completing these steps, repeat another three times. The end will result in 45 Petri dishes.

Allow dishes to sit in a warm area for 7 days.

Count the bacterial colonies, usually can be counted by eye, and record the data.

Calculate the percentage of bacteria growth coverage by placing a sheet of grid paper over the dish and calculate how many colonies take up the boxes of the grid.

Raw Data

The data demonstrated is from the counted bacterial colonies presented from each Petri dish, resulting in 45 Petri dishes. I tested each set of cultures in a 3-trial formation, the first trial with 15 dishes: three conditions tested five times. The second trial, same as the first trial, 15 dishes, three conditions tested 5 times, and the last trial, again the same. After these three trials, the bacterial colonies were counted by eye and recorded.

Qualitative Data

Directly Coughing into a Petri Dish Observations

Dish A (Coughing with No Prevention)

Trial 1

A1

A2

A3

A4

A5

Trial 2

A6

A7

A8

A9

A10

Trial 3

A11

A12

A13

A14

A15

Table: Noticeable growth in the agar medium with the control group

Coughing into Hands Observations

Dish B (Coughing into Hands)

Trial 1

B1

B2

B3

B4

B5

Trial 2

B6

B7

B8

B9

B10

Trial 3

B11

B12

B13

B14

B15

Table: Noticeable bacterium growth from an experimental group, hands covering the mouth

Cough into Surgical Facemask Observations

Dish C (Facemasks)

Trial 1

C1

C2

C3

C4

C5

Trial 2

C6

C7

C8

C9

C10

Trial 3

C11

C12

C13

C14

C15

Table: Noticeable bacterium growth from an experimental group, surgical facemask covering mouth

Quantitative Data

Number of Colonies Counted from Direct Coughs into a Petri Dish

Dish A (No Prevention)

Number of Bacteria Colonies

Trial 1

A1

0

A2

2

A3

0

A4

0

A5

0

Trial 2

A6

10

A7

0

A8

25

A9

7

A10

23

Trial 3

A11

15

A12

13

A13

23

A14

15

A15

15

Table: the amount of colonies counted in the control group; bacterium was counted by eye

Number of Colonies Counted from Covering Mouth With Hands

Dish B (Coughing into Hands)

Number of Bacteria Colonies

Trial 1

B1

2

B2

0

B3

0

B4

0

B5

1

Trial 2

B6

0

B7

6

B8

11

B9

3

B10

4

Trial 3

B11

10

B12

16

B13

23

B14

31

B15

19

Table: the amount of colonies counted in an experimental group, hands covering mouth; counted by eye

Number of Colonies Counted from Coughing into a Surgical Facemask

Dish C (Facemask)

Number of Bacteria Colonies

Trial 1

C1

0

C2

0

C3

0

C4

0

C5

0

Trial 2

C6

3

C7

1

C8

12

C9

3

C10

0

Trial 3

C11

16

C12

13

C13

18

C14

14

C15

10

Table: the amount of colonies counted in an experimental group, coughing into a surgical facemask; counted by eye

Data Analysis

Calculating the Range for Each Trial

Graphical Data

The graph above demonstrates the range between the highest count bacterial colonies and lowest. The graph gives an insight on the variation of the data, the higher the number the higher the variation. In trial 1 the variation seems lower than the rest; trial 2 and 3, however seem to have rather higher levels, the most visible in the control and the 'hands' experimental group.

Ranges of Experiment Trials

Dish A (No Prevention)

Dish B (Covering Hands)

Trial 1

2

1

Trial 2

25

11

Trial 3

10

21

Calculating the Averages for Each Trial

The averages can be calculated with a simple Excel formula:

=AVERAGE (Cell#:Cell#)

The average can also be calculated from the formula:

Data A+ Data B/ number of elements used

Averages of Experiment Trials

Dish A (No Prevention)

Dish B (Covering Hands)

Trial 1

0.4

0.6

Trial 2

13

4.8

Trial 3

16.2

19.8

The averages of the data, presented above, supports the research question since the Surgical Facemasks appear to have less bacterial growth averages.

The graph above demonstrates how the averages in each trial can be compared and presents reliable information. After each trial, the bacterial growth averages increased, but the data concludes that the surgical facemasks had a lower average of bacterium when compared to the experimental groups; Dish B presents the highest increase in average.

The graph above presents the averages of the bacterial growth in a graph that demonstrates the a clear distinction between the control group and experimental group. As one will notice the control, for the most part had more bacterial growth than the experimental groups, which supports the hypothesis. However, the experimental group or covering the mouth with hands in the experiment rose above the control in trial 3, presenting that more bacterial growth was present after coughing into hands.

The above graph presents the average of the bacterial growth coverage of the Petri dishes. The coverage was calculated by placing a grid over top of the dish and the percentage was taken from how many boxes contained colonies. The significance of the graph is demonstrated from the level pattern that the graph shows, the experiment may have had an issue with sterilization or the results had more percentage growth after each trial.

Discussion

To begin the discussion the main factor in this experiment is the validity of the results, the first look the results help proves data that support the hypothesis. The processed data presents different factors that affect the results and some parts of the data may indicate an error in the experiment.

From the data, the hypothesis is plausible from the data presented in the analysis. Starting with Chart A, the variation between the experimental group and the control group, gives an idea on the reliability of the data. The control group seems to have an upward trend in the first two trials; however, the group dips down after the third trial. The experimental group, hands covering a mouth, provides a positive upward trend from the first trial to the third trial. These upward trends show that the data in the analysis is consistent. Finally, the facemask group does not seem to have a trend, but stay relatively lower than the rest since it appears to have less bacterial growth than the rest.

Chart B, also gives some evidence that the hypothesis is supported, since the averages of the bacterial colonies present lower amounts of bacterium in the experimental groups. The chart first demonstrates the upward trend of each group, which could also be a part of evidence that the sterilization of the agar medium was flawed. However, Dish C (facemasks) proves to have the lowest count of colonies in the group, which does support the hypothesis. This is also presented in Chart C, the facemasks have a lower average, and the control and other experimental group both have similar high averages, I would say that the control group has a high average since it was always higher than the hands over mouth condition, until the third trial came.

Chart D, finally presents the amount of coverage that the bacterial colonies created, and just like the rest of the graphs, there is an upward trend. The amount of coverage provides an idea on how much the colonies grew, not only number, however, the size of the colonies that took up the Petri dish. To a surprising result the more bacteria coverage, was from the facemasks (only presented in trials 1 and 2) and the control had the least amount of coverage. I feel that there are other factors that have affect this experiment from these results, such as the environment around the experiment.

The environment around the experiment may affect the results since other germs could have contaminated the agar medium, or the Petri dishes. When a Petri dish, with the agar medium inside, is opened then all the germs surrounding the room would expose the sterile materials with new germs and bacteria. This can be proven since in my experiment there was an instance where mold was grown, since a spore had travelled its way into the dish. Now the experiment calls for complete sterility since the bacterial culture needs to demonstrate the bacteria from the person coughing, but not the bacterium or other contributing factors should be present in the culture. I proved that the agar medium was sterilized in the pre-experiment, and the results returned with no colonies presented. However, I only conducted this pre-experiment once, before I started the experiment, during the experiment when I created a new batch of agar medium, I did not test to check if the medium was sterilized.

From this factor, the experiment illustrates that there was a sterilization issue with some, if not most of the data. In the Dish B experimental group, this was covering hands over the mouth, was proved to have this issue, since it had the piece of mold growing in the agar medium. This issue could have affected not only the experimental group, but also the whole trial with the experimental group and control group. The agar medium that was prepared could have had a breach of air when being processed, or another person could have tampered with the beaker that contained the medium. If the outside air contaminated the agar medium, then the entire trial that I used the medium for would have been affected. I only created a new batch of agar medium when the old batch would run out, thus I did not carefully check each batch to see if it was sterile.

If this event occurred then the bacterium count would be higher than usual during that trial. The Dish B trial does present some evidence that the trial could have been flawed. Charts B, C, and D (the label in the upper left hand corner) give support that does suggest there was an error in my experiment. From Chart B, the averages of the colonies in each trial, the first trial had relatively low average counts, then as the trials went on the averages kept increasing at a rapid rate. Trial 1, in Chart B almost showed little to no averages. In Chart C, the upward trend of the graph proves that from the start, trial 1, the averages were low, then as the trials went on the positive increase hints the idea that there was more and more bacterium presented.

From my first "pre-experiment" I conducted, I made an excessive amount of agar medium, so that the leftovers, after this beginning experiment, could be used towards my real experiment. The results of my "pre-experiment" concluded that none of the Petri dishes had any trace of bacterium; I then conducted my first trial for my experiment, with the sterilized medium. Since the numbers from the averages of the first trial were tremendously lower, when compared to the others, this could be evidence that the first trial worked, while the other trials did not, or the medium was contaminated from bacteria before coughing. In addition, the agar medium could have not encouraged growth for bacteria. Bacteria usually live in places above freezing and some bacterium are known to live in extreme places with an acidic environment. [5] If the agar medium did not provide an environment for bacterium to grow then the results would be altered. However, from the evidence in the charts above, the more realistic idea would be that bacterium, and in some cases mold, had contaminated the agar medium, which was suppose to be fully sterile.

Conclusion and Evaluation

The experiment I conducted has shown some issues with the sterilization, hence the patterns that were illustrated through my data were not patterns but mistakes from the contaminated agar medium. The hypothesis does have some supported material to argue that it has some plausibility; however, since most of the experiment had a mistake, the hypothesis cannot be confirmed or rejected.

The experiment should be refined so the same mistakes will not be made in another experiment. If the pre-experiment was conducted more than once, then the agar medium will always be sterilized properly and the results will not be affected by contaminations. The experiment could have more trials to demonstrate whether all the data is affected by a mistake, and more data would provide more evidence towards the hypothesis.

When setting up this experiment there needs to be careful precautions and sterile tests. I feel like the cotton seal in the beaker of agar medium may provide too much air getting into the beaker. The heating plate, could also be turned up to a higher temperature to make sure that the agar medium is completely germ and bacteria free. If more sterile tests and careful maneuvers were used in the experiment, then their might have not been an issue, or I would have noticed the mistake before it was too late. I did take precautions when pouring and handling the agar medium, however, I only conducted one "pre-experiment" sterile test of the agar medium.

The design of the experiment could very well be changed, if someone were to want to test some other type of mask. Different brands of masks could be the focus of this experiment, or different types of bodily fluids could be tested, such as sneezing. The design could be about sneezing and coughing, does one produce more germs than the other? If a person wanted to test the germs on the inside of the mask, a sample can be taken from inside of the mask and placed in a culture.

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