Microorganisms are the most abundant form of life on Earth, and there are thought to be more species of them than stars in the sky.  They have many important roles, including providing plants and animals with key nutrients they need to survive and grow, and being part of complex chemical recycling systems that support all life on Earth.  Closer to home, we carry our own world of microorganisms with us wherever we go- we all have bacteria and fungi living together on our skin and in our gut, in communities called microbiomes.  These microbiomes keep us well – the ones on our skin can protect us from disease-causing microorganisms, and some in our gut produce vitamins that supplement the ones we get from our diet.  

Microorganisms don’t live alone as single cells on a surface, they live together with other microorganisms in a substance they make themselves called a biofilm, and these biofilms are everywhere- even on the International Space Station!  In this activity you will find out more about biofilms- what they’re made of, why they’re important, and when they become a problem to us, finishing off by making your own biofilm using cereal, pasta and marshmallows!