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Make fake poo

This activity will take 30 minutes, is for ages 7+ with supervision needed.

Take the long, winding journey of food to poo.

When you stop to think about it, poo is one of the most amazing, if not disgusting, things your body makes. In just over a day, your body takes in the things you need from your food – protein, fats, vitamins and minerals – and then nicely packages up the waste as poo.

What you'll need

  • 1 banana
  • 6 biscuits
  • 2 teaspoons of cocoa powder
  • About 100ml water
  • 1 teaspoon of cake sprinkles
  • A teaspoon
  • A bowl
  • A masher
  • A mixing spoon
  • Scissors
  • Kitchen roll
  • 2 plastic sandwich bags
  • A mug

Step-by-step

  • Gather your equipment

    Step 1 of 14

    A banana, biscuits, a cup of sprinkles, and plastic bowl and spoon, a measuring jug containing water, scissors, a spoon and a masher are laid out on a wooden chopping board.

    Check the kit list above and get everything ready, before things get messy.

  • Add the ingredients

    Step 2 of 14

    A large glass bowl containing half a banana, three biscuits and some cocoa powder

    Put half a banana, 3 biscuits and 1 teaspoon of cocoa powder into a bowl.

  • Mash it up

    Step 3 of 14

    Someone using a kitchen masher to mash up ingredients in a glass bowl

    Use a masher to break up the ingredients. This step represents how your food gets mashed up by your teeth and the roof of your mouth.

  • Add a bit of water

    Step 4 of 14

    Someone filling a plastic teaspoon with water from a measuring jug

    Put half a teaspoon of water in your mixture and mash it up again. The water represents your saliva – it makes food easier to chew and swallow.

  • Add more water

    Step 5 of 14

    A brown mixture with chunks of biscuit is being mixed with a wooden spoon

    Add another teaspoon of water to your mixture. This time the water represents the digestive juices that food meets in your stomach and small intestine. Then, mix it all up with a wooden spoon.

  • Scoop the mixture up

    Step 6 of 14

    Someone holds a mixture that is inside a piece of kitchen roll that has been twisted into a parcel

    Put your mixture onto a piece of kitchen roll, wrap it up and give it a gentle squeeze. You should feel the kitchen roll start to get damp as it absorbs water from the mixture. This represents how water is absorbed from our poo as it moves along our intestines.

  • Put your mixture into a plastic sandwich bag

    Step 7 of 14

    Someone using their thumbs to squeeze a brown mixture through a clear plastic sandwich bag

    Squeeze the mixture into one corner of the sandwich bag.

  • Cut a hole

    Step 8 of 14

    Above a toilet-shaped mug, someone uses scissors to snip a hole in a plastic sandwich bag which contains a brown mixture

    Use scissors to carefully cut a small hole in the corner of the sandwich bag.

  • It's poo time

    Step 9 of 14

    A hand squeezes a brown mixture out of a plastic sandwich bag. The mixture takes the shape of a fake poo.

    Squeeze your fake poo out of the sandwich bag and into a mug. Try and make your fake poo look realistic – the curlier the better!

  • Bonus – Diarrhoea

    Step 10 of 14

    Tiny, multi-coloured sugar sprinkles cover a brown mixture in a glass mixing bowl

    You can get even messier by making fake diarrhoea. Repeat steps 2-5, and then add some sprinkles to your mixture. The sprinkles represent parasites, the germs that can sometimes cause diarrhoea if we accidentally swallow them.

  • Add loads of water

    Step 11 of 14

    A plastic teaspoon pours water into a runny, brown mixture

    Put many teaspoons of water into your mixture and stir it with a wooden spoon. The mixture should look runny – we think 6 teaspoons does the trick.

  • Prepare the fake diarrhoea for exit

    Step 12 of 14

    Someone using scissors to cut a hole in the corner of a plastic sandwich bag which is filled with a runny, brown liquid

    Spoon your diarrhoea mixture into a plastic sandwich bag, squeeze the mixture into one corner and snip a small hole in the corner.

  • Time to get messy

    Step 13 of 14

    Someone squeezes a sloppy, brown mixture out of plastic sandwich bag and into a toilet-shaped mug

    Squeeze your fake diarrhoea out of the sandwich bag and into a mug. Yuck!

  • Admire your creations

    Step 14 of 14

    Two toilet-shaped mugs hold brown mixtures. One is more solid and resembles fake poo. One is runnier and resembles fake diarrhoea.

    You should have made some lovely fake poo and diarrhoea. Why do you think they look different to each other? Think about how you could experiment with different ingredients to change the texture of your fake poo.

What’s going on?

A lot of things happen to your food on its journey through your body. As it moves through you, your food is broken into smaller and smaller pieces. Your chewing starts by chopping it up and then acids in your stomach break it down even more. 

You use a lot of muscles as you digest. Muscles make your mouth chew, churn the contents of your stomach, squish food along your intestines and finally poop the leftovers out at the end of the journey.

But, it's not just muscle power that digests your food, you are helped by trillions of tiny, friendly bacteria in your intestines who digest some parts of your food that your body can't, such as plant fibres. 

Crick scientists

Unfortunately, not all of the microbes that find their way into your digestive system are friendly. Some of these are parasites that can damage the walls of your intestines, stopping them from absorbing water and nutrients. This is one of the causes of diarrhoea, like you saw when making your glittery parasite poo.  

Scientists at the Crick are studying parasites that live in human intestines. Parasites like Cryptospridium, one of the most common parasites in the world, affect hundreds of millions of people every year. 

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