It looks like this couple are dining alone.

Take a closer look –

there is hidden life everywhere.

Our world is full of organisms. They are very small – so small that they can only be seen with a microscope.

We call them microorganisms.

Microorganisms

Microorganisms live everywhere: in the air, in water, on our bodies, even inside our bodies.

There are three main types of microorganism: viruses, bacteria and fungi.

viruses

Some viruses can make you sick. They cause illnesses like chickenpox and the flu.

chickenpox
flu

This is what the flu virus looks like under a microscope.

Some bacteria can be harmful. Other bacteria are very useful.

bacteria

We add bacteria to milk to turn it into cheese or yoghurt.

We also have bacteria living in our bodies. They help us to digest food.

fungi

Many fungi are microorganisms.

We add a fungus called yeast to bread. The yeast makes the bread rise.

yeast

There is fungus growing on this rotting food. The fungus is called mould.

mould

The mould would make you ill. But mould is vital to the environment – it breaks down matter and releases its nutrients.

There are trillions and trillions of microorganisms in the world.

Many microorganisms are really helpful, but some microorganisms make us sick.

microorganisms
viruses
bacteria
fungi