The Bridge V Learning 2(clone) - Page 28

How bacteria is affected by UV light

What is bacteria?

Bacteria is a microorganism which is all around

us- even inside of us.

There are good and bad bacteria; good keeping our immune system healthy and bad causing virus and disease.

How to kill bacteria

Methods:

- Alcohol, such as ethanol

- Heat (e.g. boiling water)

- UV light

Our Experiment

The purpose of our experiment was to highlight the effects of UV light on bacteria.

1. Escherichia coli

2. Deinococcus radiodurans

3. Serratia marcescens

We used all three types of bacteria in this experiment.

Types of bacteria

Materials

1. General nutrient agar on Petri dishes, in test tubes or Erlenmeyer flasks

2. 70% ethanol

3. UV lamp, burner, automatic pipette, stopwatch

4. Tissue paper, tips, pen

5. Hockey sticks and beakers 50ml

Procedure 1

- Check pre-prepared bacterial of all three types.

- Check and prepare 4 Petri dishes for each variation.

This includes marking them with the name of bacteria and times each dish will be exposed for.

For example 30, 60 or 90 seconds.

Procedure 2

Prep table and place Petri dishes and bacteria on the side. Add tips to automatic pipettes. Prepare beaker with ethanol and hockey stick and light burner.

Shake bacterial to equalise amount of bacteria cells.