In this activity, students watch the Brainiac video Jon Tickle walks on custard on YouTube to learn more about non-Newtonian fluids at work. The activity includes a number of strategies to deepen student interaction with video content.
By the end of this activity, students should be able to:
- discuss the differences between Newtonian fluids (‘normal liquids’) and non-Newtonian fluids
- explain the scientific meanings of stress1 and strain2 as they relate to fluids
- discuss how non-Newtonian fluids change their viscosity3 or flow behaviour under stress
- explain why Jon Tickle is able to walk on custard but not on water.
Download the Word file (see link below) for:
- background information for teachers
- teacher instructions
- student instructions.
Related content
Non-Newtonian fluids change their viscosity or flow behaviour under stress as explained in the article Non-Newtonian fluids.
Videos are a useful media to demonstrate aspects that cannot be recreated in the classroom. The article Using videos in the classroom provides a number of strategies that assist students to become more actively involved with the video.
Activity ideas
Follow this with the activity Danger – quicksand!
Useful links
The YouTube video John Tickle walks on custard demonstrates the difference between a pool filled with water (a Newtonian fluid4) and a pool filled with cornflour-based custard (a non-Newtonian fluid5).
- stress: In mechanics, a force applied to a body.
In ecology and physiology, a response to a stimulus, e.g. an environmental factor, that disturbs or interferes with the normal equilibrium. - strain: In microbiology, a subtype of a species of microorganism.
- viscosity: The measure of resistance of a fluid to flow. Thick slow-flowing liquids have a high viscosity, thin fast-flowing liquids have a low viscosity.
- Newtonian fluid: A fluid that maintains constant flow rate regardless of the amount of stress applied.
- non-Newtonian fluid: A fluid that changes in flow rate depending on the amount of stress or length of time that stress is applied.