Non-Newtonian Fluid: Oobleck

Creating a shear-thickening fluid from cornstarch and water

Classroom Demonstrations Beginner (Middle School) 20 min ~$3.00

Objective

Create and explore a non-Newtonian fluid that behaves as both a solid and a liquid depending on the applied force.

Background

Oobleck is a suspension of cornstarch in water that exhibits shear-thickening (dilatant) behavior. Under slow, gentle force, it flows like a liquid. Under sudden, strong force, the starch particles jam together and it behaves like a solid. This non-Newtonian behavior occurs because the starch particles are suspended at a critical concentration where they can rearrange under slow stress but lock together under rapid stress. The name comes from the Dr. Seuss book 'Bartholomew and the Oobleck.'

Safety Warnings

  • Cornstarch is slippery when wet — clean up spills immediately
  • Do not pour oobleck down the drain — it will clog pipes
  • Non-toxic but not for consumption

Materials

  • Cornstarch (400 g)
    About 2 cups
  • Water (250 mL)
    About 1 cup
  • Food coloring (5 drops)
    Optional

Equipment

Large mixing bowl Spoon Plastic sheet or tray (to contain mess) Speaker with subwoofer (optional, for vibration demo)

Procedure

1

Place the mixing bowl on the plastic sheet. Add the cornstarch to the bowl.

2 min
2

Slowly add water while mixing with your hands. The ideal ratio is about 1.5–2 parts cornstarch to 1 part water. Add water gradually until the mixture is the consistency of thick honey.

5 min
3

Test 1 (Slow force): Gently dip your hand in and slowly pull it out. The oobleck flows like a liquid.

3 min
4

Test 2 (Fast force): Punch the surface hard. Your fist bounces off as if hitting a solid.

3 min
5

Test 3 (Shaping): Squeeze a handful quickly into a ball. When you stop squeezing, it melts back into liquid.

3 min
6

Optional: Place the bowl on a speaker playing low-frequency bass. The oobleck forms standing wave patterns and finger-like protrusions.

4 min Protect the speaker with plastic wrap

Expected Results

The oobleck flows under gentle handling but solidifies under impact. It can be rolled into a ball that melts in your palm. On a vibrating speaker, it forms dramatic standing wave patterns.

Cleanup

Let oobleck dry and scrape off surfaces. Do NOT wash down drains. Dispose of dried oobleck in trash. Wipe surfaces with damp cloth.

Details

Category
Classroom Demonstrations
Difficulty
Beginner (Middle School)
Duration
20 min
Est. Cost
$3.00
Steps
6
Materials
3

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Frequently Asked Questions

What is the objective of Non-Newtonian Fluid: Oobleck?
Create and explore a non-Newtonian fluid that behaves as both a solid and a liquid depending on the applied force.
How difficult is Non-Newtonian Fluid: Oobleck?
This experiment is rated as Beginner (Middle School). It takes approximately 20 minutes to complete.
What safety precautions are needed for Non-Newtonian Fluid: Oobleck?
Key safety precautions include: Cornstarch is slippery when wet — clean up spills immediately; Do not pour oobleck down the drain — it will clog pipes; Non-toxic but not for consumption.
What materials are needed for Non-Newtonian Fluid: Oobleck?
The main materials required are: Cornstarch, Water, Food coloring.
What results should I expect from Non-Newtonian Fluid: Oobleck?
The oobleck flows under gentle handling but solidifies under impact. It can be rolled into a ball that melts in your palm. On a vibrating speaker, it forms dramatic standing wave patterns.