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Bacteriology Science Fair Project

Bacteria in Water Coolers vs. Tap Water

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Bacteria in Water Coolers vs. Tap Water | Science Fair Projects | STEM Projects
You probably trust that a water cooler delivers clean water. But how does it compare to regular tap water? You swab water from a cooler and from a tap. Then you rub each swab across the agar in a petri dish. After five days in a cool dark place you measure the bacteria colonies. The results show whether the water cooler or the tap produces more bacterial growth.

Hypothesis

The hypothesis is that the water from a water cooler will contain more bacteria than tap water.

Method & Materials

You will prepare two petri dishes, label them, and dampen two sterilized swabs with water from the water cooler and tap water. Then, you will rub the swabs across the agar in the petri dishes and close the covers. Finally, you will measure the size of the bacteria growth in the petri dishes for the next five days.
You will need two agar petri dishes, two disinfected swabs, one bottle of disinfected water, tap water, one water dispenser and water cooler, and one marker pen.

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Results

The results showed that tap water had smaller amounts of bacteria compared to water from the water cooler. The hypothesis was proven correct - the water from a water cooler does contain more bacteria than tap water.

Why do this project?

This science project is interesting because it shows how bacteria can grow quickly in places with high levels of moisture, and how chlorine is added to tap water to kill bacteria and prevent water-borne diseases.

Also Consider

Variations of this science project could include repeating the experiment with water from different sources such as a water fountain or well, or repeating the experiment using water samples from different types of water filters.

Full project details

Additional information and source material for this project are available below.

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