Number of Bacteria Colonies Grown From Different Goggle Position

Materials and Methods

Results

Discussion and

Conclusion

Introduction

Kelly Litterer, Alexa Magliacano, Emily Vogler, Paige Woodward

-- Colonia Middle School

Hypothesis

Bacteria colonies were counted in all petri dishes on day four. There were eleven colonies of bacteria in position one. In position two we counted four colonies. In position three we counted fifteen colonies. On day seven we counted seventeen colonies in position one. In position two there were thirteen colonies. In position three there were twenty-five colonies. On day fifteen there were thirty- four colonies in position one. In position two there were thirty-four colonies. There were forty-two colonies of bacteria in position three.

The problem in my community that my team “PEAK” tried to solve was if the position of goggles when placed in the cabinet affects the way they are cleaned. This problem is

important because so many students in school use goggles and put them away in different positions. We tried to determine if the position of the goggles facing the UV

light affects the ability of the goggles bridge area to be cleaned more effectively. Facing goggles in a position which cleans it the most effectively may prevent the spread of

germs. It is said that a student’s hand holds about 1,500 bacteria cells, which means germs maybe transferred to the goggles while students conduct labs or experiments

(NSF). A UV light is used because it kills cells by damaging their DNA (Rammelsberg). We wanted to determine if the UV light kills all of the bacteria on the goggles regardless of their position. Having fewer germs on goggles may prevent the spreading of colds to other students, and since student safety is our number one priority we sought out to test

our hypothesis that goggle position my impact the ability of UV light to kill germs

The materials that were used in our experiment were petri dishes, 2 beakers, a stirring rod, sterilized Q-tips, 18 goggles, a hot plate, goggle case, refrigerator, closet and

gloves worn by each student.

1. We had students wear goggles so bacteria was transmitted to them. Then we sterilized them for 15 minutes in the goggle cabinet.

2. We placed the goggles in three different positions known as position 1, position 2, and position 3, (Figures 2,3,4).

3. We prepared the Agar by following the directions from a Steve Spangler Science bacteria growing kit.

4. We lined up 3 rows of petri dishes, and each row contained 6 petri dishes. 5. We poured Agar into all 18 petri dishes, (Figure 6).

6. The petri dishes were then put into a fridge so that they could gel.

7. When the Agar solidified, we used sterilized Q-tips and swabbed the bridges of the goggles (Figure 7) and traced a “Z” on the gelled Agar, (Figure 8).

8. We then put the Agar in a closet for 4 days and then took them out and counted the number of bacteria colonies in each dish. When then put the petri dishes in the closet until day 7 then day 15 and counted the bacteria colonies in each petri dish. (Figures

9,10,11).

Our hypothesis was that if goggles are positioned on the left side with the lens facing up in a goggle case, then less bacteria will be present on the bridge than on goggles with the lens facing down.

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Number of Bacteria Colonies Grown From Different Goggle Positions

Figure 1:Number of Bacteria Colonies Grown From Different Goggle Positions

Position 1 Position 2 Position 30

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Day 4

Day 7

Day 15

Each team member had an equal amount of work. We each had about four Mission Folder questions to answer. We stayed after school and came during lunch to make sure our experiment was finished on time. One person counted and recorded the number of bacteria colonies in each petri dish. Another person analyzed our data and made a graph. The third person collected data by taking pictures. The last person wrote down the steps of our procedure and created a list of materials that we used.

Figure 2: Goggles are about to be sterilized in different positions.

Figure 3: The bridge of a goggle.

Figure 4: Preparing the agar.

Figure 5: Pouring the agar in the petri dishes.

Figure 6: Swabbing the bridge of the goggle.

Figure 7: Tracing a “Z” in the gelled agar.

Figure 8: Sample of the bacteria growth after 4 days on goggle position 1 & 2.

Figure 10: All of the bacteria colonies after 1 week.

Figure 9: Bacteria growth after 4 days on goggle position 3.