Carly Werner Period 6 May 23, 2014 Discovery Project Biology 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: Antibiotic Soap and Hot Water Hot Water Rinse Salt Water Soak Hydrogen Peroxide Solution Number of Trials: 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 13.5 Salt Water 10.0 7.0 8.5 No Method 11.0 9.0

Graph Amount Of Bacteria Still Growing (Bacterial Colonies) Disinfectant 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. *Elaborate