Microorganisms Lesson for Kids

Instructor: Dacia Upkins

Dacia has taught all core elementary subjects for 14 years with a Master's degree in Urban Teacher Leadership.

In this lesson, you will learn about a world of living things you can't even see. By the end of the lesson, you will be able to define microorganism and identify some common groups of them.

What Is a Microorganism?

Take a look at your fingertips. Do you think they're clean? Well, millions of living things are on the tip of your finger. There are even more on your hands. It's true! These little things are called microorganisms.

'Micro' means small, and 'organism' means living thing. Microorganisms are very, very small living things. And they live all over you and everything else.

How Can We See Microorganisms?

All living things are made up of cells, which are known as the building blocks of life, like Legos. (An adult human has over 37 trillion cells.) But almost all cells, individually, are too small for us to see with just our eyes.

Since most microorganisms are made of only one cell, scientists see them by using microscopes, which are tools used to see very small things up close. The microscope allows us to see an invisible world we'd never know existed. The world of microorganisms includes things like bacteria, fungi, and protists.

The microscope is an instrument used to see very small things like microorganisms.

Bacteria: Friend or Enemy?

Those little creatures partying on your fingers are a microorganism called bacteria. Gross, right? Well, not exactly. Bacteria live almost everywhere, including in our stomachs, dirt, and in your favorite meal. And a lot of them are actually good for us.

Good bacteria in our stomachs help us to digest the food we eat. Other bacteria found in soil help break down dead leaves and other things to make that soil rich and useful for plants to grow in.

But beware - some bacteria are harmful, like ones that can cause your food to go bad or make you sick. It's important to keep your body and the things around you clean so that you can avoid exposing yourself to these harmful bacteria.

Bacteria is a microorganism that can be helpful or harmful.

Do You Eat Fungi?

Fungi are usually easier to see than bacteria, because a lot of them live in large groups, called colonies. In fact, you've probably enjoyed fungi at dinnertime. No, not the kind that can grow between your toes, but the common kind that is baked into our favorite breads (yeast) or sprinkled on many pizzas (mushrooms).

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