Before the COVID19 pandemic started in 2020, how much did you know about microorganisms? If you said not much, you’re not alone. The last two years have been full of people talking about microorganisms and the role of vaccines.

As a virologist, I’ve learned so much about microorganisms over the past year. Despite all the negative talk about microorganisms, they are a vital part of everyday life and health. That’s why I’m really excited to share a little about what I know.

I’ve also prepared a worksheet that you can use with your family to learn some science about microorganisms and vaccines for some homeschooling science fun. This microorganism and vaccine worksheet is perfect for a home lesson to introduce kids to the microorganisms and science behind vaccines. It’s also ideal for both primary school and high school students as it involves some critical thinking, online research and problem solving all in one!

Teachers, feel free to assign this worksheet for your students to do at home or in class!

Why microoorganisms are good for you

I love yoghurt, and without microorganisms like lactobacillus bacteria, we would all be missing some of our favourite breakfasts. Vegemite and sourdough are other breakfast staples, and both would not be possible without yeast and bacteria.

Aside from food, microorganisms are very useful in some industries. E10 petrol has 10% ethanol added to the petroleum which can be produced using Saccharomyces yeast. There are even some bacteria which can break down plastic and may be used for recycling in the future!

But microorganisms aren’t limited to what they can do for us outside of our body, and are also an important part of what goes on inside our body. Every person has colonies of microorganisms living on and in them. Together all these microorganisms are called the microbiome. Each person’s microbiome is unique, and can be used like a fingerprint to help identify people – forensic scientists are actually working on this for future crimes.

Recently, there has been more of a focus towards researching and understanding how we can live in symbiosis with our microbiome by doing things like eating the right things and avoiding unnecessary antibiotics. Microbiomes are important for healthy digestion, skin, moods, and even helping prevent cancer.

Many strains of “good” Escherichia coli (E. coli) bacteria live in our gut and help keep the “bad” strains out. This is what the probiotics industry is all about – introducing “good” microorganisms into our body to keep us healthy. These good microorganisms help us digest milk and fibre.

However, microorganisms are not all good, and some can cause serious diseases.

When microorganisms go bad

The microorganisms we have been hearing about recently in the news are the bad kind, also known as pathogens. A few different types of pathogens can cause disease – bacteria, viruses, fungi and protozoans. Bacteria, fungi and protozoans are all alive and live in the environment around us. Most often, they live happily and we don’t know they are there. But sometimes, these microorganisms colonise us and make us sick.

Viruses, on the other hand, are not alive and need a host like us to survive. They also do not normally exist in the environment and only exist in hosts. To spread themselves to other living hosts, viruses have evolved to make us sick. And they have become very good at it!

The easiest way to avoid getting sick from microorganisms is to keep up good hygiene practices. This includes washing hands before eating, brushing teeth regularly and not eating food after it’s expiry date. However, this doesn’t always work, and sometimes medical prevention or treatment is the only option.


Vaccines are used to prevent illness from microorganisms – some common ones are MMR (measles/mumps/rubella viruses) given to every child in Australia and the flu shot (influenza) developed each year.

And of course, we’ve all heard of the vaccines developed against COVID19 produced by AstraZeneca, Moderna and Pfizer, which protect against SARS-CoV2. There are a few different ways that vaccines can be made, but they all do the same thing – introduce the microorganism to your immune system so that your immune system will recognise it in the future.

That’s the really neat thing about vaccines, they don’t kill the viruses like antibiotics kill bacteria. Instead, they teach your body to recognize the bad viruses before they can do a lot of damage. To put it another way, vaccines train your body to fight back.

What you’ll learn in this worksheet

With all the talk about bacteria and viruses, I’ve met a lot of kids that are confused. That’s why I feel that it’s important to learn about microorganisms and also important to understand what happens when they go bad. This activity will teach kids about bad microbes and why it is important to have good hygiene, including hand-washing and brushing teeth. Hopefully after this lesson you won’t have to remind them!

After hygiene, the worksheet explains the need for vaccines and how they work. Vaccines are a very hot topic in the current climate – it seems none of us can go one day without hearing statistics about the current SARS-CoV2 vaccination rate! But there is a lot of confusing information out there. A basic understanding of the science behind vaccines can help you and your kids interpret the information around them.

The activity finishes with interpreting a government ad – one of the most important skills anyone can learn. Children have increasing exposure to social media, so I think it’s vital to teach them to stop and think about what they see – that’s what Arludo is all about! This activity aims to get them to think critically and come up with their own conclusion.

Stay tuned for future post that discuss the vital roles that microorganisms play in the ecosystems around us, including decomposing and recycling. Microorganisms are a great science topic to teach your kids about the hidden world around them, and the tiny creatures that influence their everyday life.