Fake Blood Science Experiment

Learn how your blood clots AND create a homemade last-minute addition to your Halloween costume with Upstart’s coagulating fake blood recipe.


What you need…

  • 1/2 cup water

  • 1 tsp Gelatine

  • Red food colouring

  • Black food colouring (optional)


WARNING: This fake blood recipe uses food colouring so will stain clothing and temporarily stain skin, so make sure you’re wearing clothing that you don’t mind being permanently turned red while using this fake blood.


What to do…

REMEMBER: Always ask a caregiver before using hot water.

  1. Get an adult to help you to bring 1/2 cup of water to the boil.

  2. Add 1 teaspoon of gelatine to the water and stir until the gelatine crystals are dissolved.

  3. Transfer the mixture to a small bowl and allow to cool for 15 minutes.

  4. Once cooled, add 3-4 drops of red food colouring and combine.
    Note: keep adding food colouring if it doesn’t turn as red as you like.

  5. Real blood is a dark red colour. To give your fake blood a more realistic look, add 1-2 drops of black food colouring to the mixture and combine.

  6. Allow the mixture to cool to room temperature.

  7. Carefully splatter some fake blood on a sheet of baking paper.
    As time passes, the fake blood will thicken to imitate how real blood coagulates. Leave it long enough and it will set hard as scabs do.

  8. Once your fake blood reaches the desired consistency, you can use it on pretend wounds and even vampire fangs!


What we learn…

Fake wound with Upstart’s fake blood added

When you splatter your fake blood onto a piece of baking paper, you will observe it slowly start to “coagulate” - turning from liquid fake blood into a gel and, eventually, a more solid substance.

When we get a cut or scrape, it causes holes in the walls of our blood vessels (tube-like structures that carry blood all over our body). When this happens our body almost immediately rushes to form clots that act as a natural sticking plaster to stop the blood vessels from bleeding. This process is also what helps your body to form scabs.

Three substances in your blood work together to make clots:

  • platelets

  • clotting factors

  • and blood cells.

These three substances stick together to turn liquid blood into a solid clot. The process is called coagulation.


Did you give it a go?

Send us a photo of your fake blood experiment in use and you might find your creation featured in a future issue of Upstart magazine OR on Upstart online… AND win a prize!