Kitchen Chemistry: Making Non-Newtonian Fluids with Cornflour

What You’ll Learn

After this activity, you and your child will:

• Understand the unique properties of non-Newtonian fluids
• Create and experiment with oobleck (a cornflour and water mixture)
• Discover how materials can behave differently under various conditions
• Develop scientific observation and investigation skills
• Connect scientific concepts to everyday experiences

Safety First

Before diving into our kitchen chemistry adventure:

• Cover your workspace with newspaper or a plastic tablecloth
• Wear old clothes or an apron
• Keep ingredients away from eyes and mouth
• Have paper towels ready for quick clean-up
• Supervise children throughout the activity
• Store any leftover mixture in an airtight container
• Dispose of the mixture in the bin, not down the sink

What You’ll Need

Essential Materials:

• 2 cups of cornflour (sometimes called cornstarch)
• 1-1.5 cups of room temperature water
• A large mixing bowl
• A spoon or spatula
• Measuring cups
• A tray or baking dish (for containing spills)

Optional Materials:

• Food colouring
• Small toys for testing
• Timer
• Magnifying glass
• Clear container for observation
• Camera or phone for recording observations

The Science Behind Non-Newtonian Fluids

Before we start mixing, let’s explore what makes non-Newtonian fluids so special. Usually, liquids like water and oil maintain the same thickness (viscosity) no matter how you interact with them. These are called Newtonian fluids, named after Sir Isaac Newton.

However, some substances break this rule! Non-Newtonian fluids change their behaviour depending on how much pressure or force you apply to them. The cornflour mixture we’re making (often called oobleck) acts like a liquid when handled gently but becomes solid-like when squeezed or struck.

This happens because cornflour particles are:

• Suspended in water rather than dissolved
• Able to slide past each other slowly when moving gently
• Forced to bump and lock together when pressure is applied
• Quick to separate again when the pressure is released

Let’s Get Started!

Step 1: Prepare Your Mixture

1. Pour the cornflour into your mixing bowl
2. Gradually add water while stirring
3. Mix until you achieve a thick, smooth consistency
4. The mixture should feel liquid-like when poured but resist quick movement

Step 2: Initial Observations

Encourage your child to:

• Describe what they see
• Note how the mixture feels
• Compare it to other substances they know
• Make predictions about how it will behave

Step 3: Investigation Time!

Try these experiments:

The Rolling Ball Test

• Roll a small ball of the mixture in your hands
• Observe how it becomes firm
• Stop rolling and watch it melt

The Quick vs Slow Challenge

• Slowly dip your finger into the mixture
• Now try to jab it quickly
• Compare what happens

The Pressure Test

• Fill a container halfway
• Tap the surface gently, then harder
• Notice how the surface responds differently

Extension Activities

Sound Science

• Stretch the mixture across the top of an empty container
• Tap it gently with a spoon
• Record the sounds it makes at different consistencies

Art and Science

• Add different food colours to separate batches
• Create patterns by dragging fingers slowly
• Observe how colours mix when forced together

Speed Investigation

• Time how long it takes different objects to sink
• Compare sinking speeds at different mixture consistencies
• Record and graph your findings

Troubleshooting Tips

Mixture Too Runny?

• Add more cornflour gradually
• Mix thoroughly between additions
• Test consistency by lifting and dropping

Mixture Too Thick?

• Add water one tablespoon at a time
• Mix completely before adding more
• Check by letting it drip off the spoon

Mixture Separating?

• This is normal! Just mix it again
• Store in an airtight container
• Make fresh mixture for best results

Real-World Connections

Non-Newtonian fluids aren’t just for fun – they’re all around us! Here are some examples:

• Tomato sauce (thicker until shaken)
• Quicksand (more resistant with movement)
• Silly putty (stretches slowly, snaps quickly)
• Paint (changes thickness when brushed)

Taking It Further

Discussion Questions

• What other materials might behave similarly?
• How could this property be useful in everyday life?
• What happens if we change the temperature of the mixture?
• Why doesn’t the mixture stay solid or liquid?

Scientific Method Practice

Encourage your child to:

1. Form questions about the mixture
2. Make predictions
3. Design simple tests
4. Record observations
5. Draw conclusions
6. Share discoveries

Clean-Up and Storage

• Dispose of mixture in the bin (not sink)
• Soak bowls in warm water
• Let dried mixture crack and brush off
• Store unused mixture in sealed container
• Use within 2-3 days

This simple kitchen experiment introduces complex scientific concepts in a hands-on, engaging way. Through play and observation, children develop an understanding of:

• How materials can have multiple properties
• The relationship between force and matter
• Scientific observation and recording
• The joy of discovery through experimentation

Remember, the goal isn’t just to create an unusual substance – it’s to spark curiosity, encourage questions, and develop scientific thinking skills that will last a lifetime.

Recommended Resources

Australian Resources:

• CSIRO Double Helix Magazine
• Primary Connections (Australian Academy of Science)

General Resources:

• Royal Society of Chemistry Education

Educational Standards Alignment

This activity aligns with the Australian Curriculum Science Understanding (ACSSU077) and Science Inquiry Skills (ACSIS065, ACSIS068) for Years 3-4, focusing on:

• Properties of materials
• Planning and conducting investigations
• Making predictions and observations
• Recording and processing data
• Communicating findings