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Snot is wonderful stuff!

Here’s some gross science for you to get hands-on with! This gloopy recipe produces some amazing fake snot.

You will need

• Kettle
• Water
• Measuring cups and spoons
• Spoon for mixing
• Teacup or mug
• Gelatine
• Glucose syrup
• Green food colouring (optional)

Safety: This activity uses boiling water. Ask an adult to supervise and help if needed.

First aid: If you burn or scald yourself, put it under cool running water for 20 minutes. If needed, seek medical advice.

What to do

1. Fill the kettle to the minimum line and boil the kettle.
2. Carefully measure ¼ cup of boiling water, then pour it into a teacup or mug.
3. Add 3 teaspoons of gelatine to the water in the cup, adding one teaspoon at a time. Stir carefully between adding each teaspoon, remembering to use a different spoon for measuring and for stirring.
4. Add ¼ cup of glucose syrup to the water and gelatine.
5. Add a few drops of green food colouring to the mixture (optional).
6. Stir gently until the mixture combines.
7. Wait for the liquid to cool for 10 minutes.
8. Try playing with your fake snot. It will get thicker and gloopier until it sets solid!

What’s happening?

Snot is wonderful stuff! It’s also called mucus and it’s not just produced in your nose. You have mucus-producing cells pretty much anywhere there’s an opening into your body. That includes your eyelids, mouth, throat, lungs, and even your private parts!

Some mucus is there to make things slippery. For example, mucus in your throat helps food to slide into your stomach without sticking or scratching.

In your nose and lungs, it has a different job. This mucus catches smoke, dust and other harmful particles. It’s also quite good at collecting viruses and bacteria.

There are anti-infection cells in your snot called neutrophils. When neutrophils are fighting germs, they release a chemical that contains a green colour. So if your snot is green, there’s a fight going on in your nose!

Mucus is mostly water and some chemicals called mucins. Mucins are proteins, and they can join together to make a gel. This gel acts something like a net to catch particles. The mucins also have a sugar coating that makes them good at holding on to water, which is why mucus is so slippery.

The fake mucus you’ve just made is trying to do the same thing. Gelatine is made of proteins that stick together to make a gel, holding lots of water. And there’s plenty of sugar in the glucose syrup too!

Real-life science

CSIRO scientists are experts at fake snot! Recently, they ran an experiment to see how long the virus that causes COVID-19 could remain infectious on different surfaces.

The virus that causes COVID-19 disease is called SARS-CoV-2. To make the experiment as realistic as possible, the researchers mixed up a fake snot with SARS-CoV-2 virus particles in it. They applied this mixture to different surfaces. The scientists used a different recipe to the one in this activity though!

As for the results, SARS-CoV-2 is very hardy. In our laboratory, with no exposure to sunlight, the virus survived for 28 days on a range of surfaces including mobile phone screen glass and banknotes. In real life, exposure to sunlight, humidity and different temperatures all affect how long a virus can survive in the environment.

Viruses can survive on surfaces and can transfer to your hands. So remember to wash your hands regularly!

If you’re after more science activities for kids, subscribe to Double Helix magazine!