Bacteria Field
This STEM activity is suitable for preschool and elementary school levels. It's important to impart the knowledge that there's an unseen process in nature to children. During the activity, it can be mentioned that up to a billion living organisms can inhabit just one gram of soil. It should be emphasized that these organisms not only live in the soil but also on our skin, and we need them for our health, although some of them can make us sick. Afterwards, children's ideas should be sought with a question like "What do you think Tako and Ruka will do?" and then the activity should begin.
Objective of the Activity:
Directing children's interests towards nature
Contributing to the awareness of "Nature" and "Environment" among children
Increasing children's sensitivity to living and non-living beings around them
Raising awareness about the unseen workings of nature
Highlighting that all living things in nature depend on each other in a system and order
Once Upon a Story
Tako and Ruka woke up early one Saturday morning. After they both had breakfast, Tako got permission from his grandfather and left home with Ruka to go to the nearby forest area. The weather was very nice. Excitedly, they went towards the forest area and started playing and exploring. They saw different mushrooms and snails with colorful shells. Ruka tried to eat the mushrooms, but since many mushrooms can be poisonous, Tako didn't let her. Ruka didn't like this situation at all, but she listened to Tako. After all, Tako knew this world, which was foreign to Ruka, better.
They didn't realize how time passed and got hungry. They decided to return home. Although Ruka wanted to go quickly because she was very hungry, they walked home talking with Tako. Tako's grandfather always cooked very delicious meals for them, and Ruka loved those meals. When they entered the house, Tako immediately went to his room to change his clothes, and he saw Ruka heading towards the kitchen while going to the bathroom to wash his hands and face.
Tako waited for Ruka to wash her hands. Then they enjoyed their meal. Afterwards, Tako quickly put on his lab coat. They gathered the materials and started the experiment. Let's do this experiment too.
Materials
Activity
Step I
First, let's put on our plastic gloves. We shouldn't touch the bread yet. After putting on our gloves, we need to take cotton swabs and rub them on the places we use most at home. For example, we can rub one cotton swab on a frequently used door handle. We can rub another cotton swab on a cellphone. Don't rub these two cotton swabs anywhere else, okay?
Step II
With our gloves still on, let's take a slice of bread. Rub the cotton swab that you used on the door handle lightly on the bread. It should touch all over the bread. Don't press too hard to avoid breaking the bread. Then put the bread in the Ziploc bag and seal it. Write "door handle" on the bag with a marker. Repeat the same process for the cotton swab you used on the cellphone.
Step III
Now it's time to take off the gloves. This next step is very simple. If you are at school, play a lot during recess. If you are at home, rub your hands on the walls, furniture, doors, kitchen counters, balcony, and everywhere else you can think of. Then take another slice of bread. If you want, you can press the bread lightly between your hands. Put it in a Ziploc bag and label it "dirty hand."
Next, wash your hands thoroughly. Wash for at least 2 minutes with soap, dry them, and take another slice of bread. Put it between your palms, then package it and label it "clean hand."
Step IV
Now, place the bags in a dark place without direct sunlight and let them sit for 5-6 days. It's important that the bags are in a dark place. Afterward, take the bags out without opening them and see what has happened. Do you see colorful spots and cotton-like things on the bread? What do you think they are? Which bread has the most of these? Why do you think that is?
What's Happening?
As Tako said, there are many living organisms that are invisible to the naked eye in nature. Bacteria, viruses, fungi, germs, and many others. These bacteria live everywhere. In fact, many of them are found in our bodies too. Some of these organisms are beneficial to us, but some can make us sick. Germs living on tables, doors, or in dirty water can stick to our hands if we touch them. When we eat without washing our hands, they can get into our stomachs with the food and spread throughout our bodies, making us sick.
In this experiment, we created an environment suitable for their growth. Bread is a good source of nutrients for living organisms that need food because they are alive. Think again about what could happen if we eat bread that we touched with dirty hands!
Attention!
This activity takes about 1 week to complete. The bread should be stored in places without direct sunlight and not too humid. Do not store it in the refrigerator.
The Ziploc bags should not be opened while examining the bread.
If you wish, you can wear a mask and take small pieces of the bread to examine under a microscope.
Evaluation Questions
How long did it take for changes to occur in the bread?
In which bread slice did the most change occur?
Where do you think the dirtiest place could be?
Why is it important to wash our hands?
Why do you think doctors always wear gloves?
Why is the length of our nails important?
Do you think it's possible to keep every place clean in the surroundings?
What do you think the role of these organisms in nature might be?
Activity File
Scientific Concepts
The scientific concepts related to this activity include: Bacteria, Virus, Single-Celled Organism, Arthropod, and Tardigrade. You can conduct your own research to discover interesting facts about these concepts!