Introduction

Bacteria are found on all surfaces, whether they are alive or dead. There are good and bad bacteria that could either help you or hurt you, for example, good bacteria lives in your stomach which aids in digestion, and there are bacteria such as salmonella which can make you extremely sick. The purpose of my project is to see what type of metal door handles, circular or rectangular bacteria thrive on.

Bacteria have been on the planet for more than 3.5 billion years, ( “Team, N. B.”, 2018) making them the oldest known life-form on earth, can you believe that! scientists who study bacteria are called microbiologists or bacteriologists. (“Kazilek”, 2014).

Bacteria are found everywhere in the environment - air, soil, and water. Bacteria and viruses can travel through the air, causing and worsening diseases. When someone sneezes or coughs, tiny water or mucous droplets filled with viruses or bacteria scatter in the air or end up in the hands where they spread on surfaces such as doorknobs. Crowded conditions with poor air circulation can promote this spread of bacteria. Effective ventilation may also help keep bacteria, viruses, and other pollutants out of the indoor air. (“Sources of Bacteria”, n.d.). Research shows that airflow and ventilation can affect how diseases spread indoors. (“Bacteria and Viruses,” n.d.).

Thousands of types of bacteria are known. Many more kinds have not yet been described or even discovered. Scientists estimate that 5 x 1030 bacteria live on our planet at any one time. (Kazilek. ,2014 ). The most common bacteria are about,100,000th of a centimeter. This means Clumped together, all of those bacteria would weigh much more than every animal and plant living on Earth, combined, that’s a lot! Bacteria is most frequently shaped like a sphere, rod, or spiral. Some bacteria vary and can be shaped like a comma or corkscrew.

Bacteria can survive in many types of environments in and on the human body. Most bacteria cause no harm to people.

For bacteria to survive, they must leave an existing reservoir. Bacterial infections may be marked by localized redness, inflammation, pain, or swelling. Bacterial infections may be transmitted through direct or indirect contact with a reservoir of infectious bacteria. Certain bacteria can survive outside of a host and remain infective for extended periods of time To survive and reproduce, bacteria need time and the right conditions: food, moisture, and a warm temperature. ( “Food Safety and Inspection Service.”, n.d.)Bacteria do not grow and multiply the same way as animals or humans. They take in nutrients and reproduce by dividing – one bacteria splits and becomes two bacteria, two become four, four become eight, and so on.

Doubling can occur quickly if the conditions – enough nutrients, proper temperature, adequate moisture, etc. - are suitable. In 2 hours, these bacteria can become so great in number that they may cause an illness or form toxins that cause illness. potentially, one bacteria can multiply to more than 30,000 in five hours and more than 16 million in eight hours. ( “Food Safety and Inspection Service.”, n.d.)

Almost all door handles carry bacteria. Did you know that in 15 minutes, 24 people touched a door handle on average? That is why we have to make sure we wash our hands thoroughly to try to prevent the spread of bacteria.

My hypothesis for my project is since rectangular shaped door handle has less surface than the circular doorknob, it will have less bacteria.