3 Astonishing Microbiology Experiments Kids Can Do at Home

Kids are naturally inclined to explore and understand the world around them — From the millions of stars scattered across the cosmos to the most minuscule species roaming the earth. 

Microbiology is an integral pillar in their quest to understand the universe. And there are many awesome ways to introduce this complex concept in a child-friendly and engaging manner: 

• First, through the use of microscopes. We have curated a complete list of microscopes for students, perfect for children of all ages! (Spoiler alert: The SuperScope 3-in-1 Digital Microscope is the best one to get)

• Second, by performing fun microbiology experiments. The internet offers a wide collection of microbiological experiments that kids can do at home. 

Here are 3 of the most astonishing microbiology science projects you and your child can perform together.

Note: If you’re not a big fan of running to the store to get some experiment materials, our MicroExplo Science Kit contains every tool your child needs to perform 3 unique experiments (other than the ones listed here!)

Anyway, here are the 3 microbiology experiments!

3 Stay-at-home Microbiology Experiments

1. Extract Your Own DNA!

Wait, hold up!

Isn't DNA a part of genetics, and not under the field of microbiology?

Well, technically, microbiology means the study of tiny organisms. In contrast, DNA is the microscopic blueprint that makes up the entirety of an organism.

What I’m saying is, to some degree, we can view DNA as a part of microbiology too!

In this first experiment, kids will learn how to isolate their DNA from their cheek cells using a set of simple instructions and a bunch of kitchen items.

Here are the things you’ll need:

• Salt

• Warm water

• Beaker or glass

• Dish soap

• Isopropyl alcohol (70% or higher)

Instructions:

1. Chill your alcohol bottle in the fridge for at least 30 minutes.

2. Pour two cups of warm water into your glass or beaker.

3. Mix and stir a tablespoon of salt into the liquid to create a salt solution.

4. Gargle ¼ of the salt solution for 1 minute and then spit it back into the salt solution. The rinsed liquid contains your cheek cells.

5. Add 2 drops of concentrated dish soap to the solution and slowly stir. Make sure that no bubbles are formed when stirring.

6. Pour ½ cup of the chilled alcohol into the salt solution gently to not violently disturb the solution. (Note: one trick is by making the alcohol run by the sides of the beaker)

7. Wait for several minutes and check the solution.

Result:

A fibrous snot-like string would clump up or form in the solution. This is your cheek cell DNA. Gross, but a wonderful result of some cool science!

Explanation:

DNA (or deoxyribonucleic acid) is a double-helix hereditary material invisible to the naked eye, but the added series of materials enabled us to see DNA. Using salt neutralizes the DNA and protects it from being dissolved by water. The dish soap opens up the cells in a process called “lysing” and removes the surrounding fats and proteins. Lastly, alcohol washes the DNA and precipitates it into a visible form. 

2. Make a Winogradsky Column!

Microbes are the beginning and end of the food chains existing on earth. They produce the materials that other species will use to thrive while breaking down materials that have reached their end.

Making a Winogradsky column will help kids study microbes by creating their own micro-zoo!

(Fun Fact: The experiment was named after Sergei Winogradsky, a Russian microbiologist known for his work on soil microbes.)

Here are the things you’ll need: 

• 4 similar plastic bottles (around 1.5 L soda bottles)

• Black Marker

• 2 hard-boiled eggs

• Shredded newspaper

• Shovel and gloves

• Mixing bowls

• Pond mud or rain puddle mud or river bed mud

• Cling wrap and rubber bands

Directions:

1. Using the shovel and gloves, dig up mud (from a pond, rain puddle, or river bed) and fill the bucket. Remove all stones, twigs, and other solid materials.

2. Cut the tops of the 4 plastic bottles to uniform heights.

3. Using the marker, label each of the 4 bottles: nothing, egg, newspaper, newspaper + egg.

4. Saturate the mud with water and mix until it obtains a mud shake-like consistency.

5. Pour the mud shake into the “nothing” bottle until about 80% full.

6. In a mixing bowl, add some mud shake, and break down one hard-boiled egg into the mud. Mix until the egg incorporates the mud shake, then pour into the “egg” bottle to 80% full.

7.  In another mixing bowl, pour some mud shake and place some shredded newspaper into the mud. Mix until the newspaper incorporates the mud and then pour into the “newspaper” bottle to about 80% full.

8. In another mixing bowl, pour some mud shake and add some hard-boiled egg and newspaper into the mud. Mix until fully incorporated, then pour into the “newspaper + egg” bottle to about 80% full.

9. Cover the lids of all bottles with plastic cling wrap and secure them with rubber bands.

10. Place them in an area where one side of each bottle can receive sunlight while the other is kept in the dark.

11. Every 4 days for 5 weeks, record changes you see in all 4 setups.

Result:

The sides receiving sunlight will exhibit green growth. The sides kept in the dark will remain as is. The bottle with the egg will exhibit growths of black, green, and purple colors. While the one with newspapers, brown, orange, red, and purple coloring will appear. The bottle that used both the egg and newspapers will have the most colors and growth.

Explanation:

The green growths from the illuminated sides are cyanobacteria and algae, which need light to grow. 

Egg contains sulfur which facilitates the growth of sulfur-consuming bacteria. The growths in the “egg” bottle are groups of certain anaerobic bacteria: green sulfur bacteria, purple sulfur bacteria, and sulfate-reducing bacteria (black). 

On the other hand, newspapers contain carbon used by some bacteria to thrive. The “newspaper” bottle grew purple non-sulfur bacteria.

The “egg + newspaper” bottle contains both sulfur and non-sulfur bacteria.

3. Put bacteria to work!

Yogurts are one of the most loved food by youngsters, and microbes are the ones that make it possible! In reality, humans have been making yogurts for thousands of years, and in this activity, your child can make their very own yogurt too!

Here are the things you’ll need: 

• 1 Liter of whole milk

• 100 ml of full-fat yogurt

• Saucepan

• Thermometer

• An oven that can go below 50°C (122°F)

Directions:

1. Pour the milk into the saucepan and heat to 90°C (194°F), don’t let it boil.

2. Take the saucepan off the stove and let it cool until 40°C (104°F).

3. Add the yogurt to the milk and slowly and thoroughly mix the two.

4. Cover the saucepan with a lid, place it inside the oven with a temperature set at 35-40°C (95-104°F), and then wait for 6-8 hours.

5. Once the yogurt starts to be denser and thicker than regular milk, then your yogurt is ready.

6. Transfer to a separate container and refrigerate for a couple of hours.

7. Bon appétit!

Result:

You get thick milk with viscous consistency — that’s the yogurt!

Explanation:

Yogurt is done by two bacteria, namely: Streptococcus thermophilus and Lactobacillus delbrueckii bulgaricus. They convert the lactose in milk into lactic acid, hence the familiar and distinctive sour taste.

Heating the milk kills bad bacteria and makes for a richer end product. The low oven temperature is the perfect setting to incubate the bacteria and facilitate their growth in the milk. Refrigerating the yogurt doesn’t do anything scientific, but you can never go wrong when eating chilled yogurt!

Microbes are amazing! Although they’re invisible to the naked eye, the impact of their works is extensive and critical for the world’s food chain. The microbiology experiments above aim to introduce microbes in an engaging way to kids, so we hope you have fun doing them. 

Who knows, you might raise a budding microbiologist after doing them!

Our MicroExplo Has Them All!

You can do tons of fun microbiology experiments at home, but you’ll be outsourcing the materials somewhere else to complete the activities. If you’re not a big fan of driving to get the materials, why not buy a science kit that contains every tool your child will need? 

TheSTEMkids’ MicroExplo kit has all the things your kids need to conduct 3 exciting microbiological experiments. Read more about it on its dedicated product page, and feel free to check out our other science gadgets too!