Making slime at home is one of the easiest ways to turn a rainy afternoon into a hands-on science lesson. This messy play activity sparks children’s natural curiosity and gives them a fun, practical introduction to real STEM concepts — all while they think they’re just playing! Tracey-Jane Cassidy MA MSc, CEO of Junior Einsteins Science Club, shares her simple recipe for safe, easy slime.
How to Make Safe, Simple Slime
Scientific concept: Non-Newtonian fluids — liquids that don’t behave the way water does!
To make your slime you will need:
- 1 packet of cornflour
- Water
- A bowl or container
- A cup or jug for the water
- Gloves (optional)
- Food colouring (optional, but fun!)
Method for slime:
1. Place all your cornflour into your bowl or container.
2. Get a cup of water and add a few drops of food colouring if using.
3. Add the water slowly to the cornflour while gently stirring.
4. Keep adding water until you reach a “slimy” consistency! You will need about 2 cups of water.
5. Your slime is ready to play with!
Once your slime is ready, stir it slowly with your hand and notice how gloopy and drippy it is. Then try punching it very quickly — suddenly it becomes as hard as stone and not like slime at all. Crazy, right?
You may also enjoy reading: Hands On Science for Your “Junior Einsteins” Parties, Camps and Classes and Events.
The Science Bit
Your slime is made up of tiny, jagged little pieces that look like rocks under a microscope. When you punch the slime, those jagged pieces jam together and your hand can’t push through. But if you move the mixture around gently, the pieces have time to tumble over each other, and the water moves in between them, so the mixture flows like a liquid.
You’ll find this slime experiment, along with nine other fun science experiments, in the Junior Einsteins Science Club book Slime, Bubbling Potions & Exploding Rockets.
You may also enjoy reading: Watch Out! Some Slime for Kids Contains Dangerous Levels of Boron.
Junior Einsteins Science Club
Creating science experiments — and making mistakes along the way — helps build children’s confidence and self-esteem. Group experiments like this one encourage creative thinking, teamwork, imagination and problem-solving. At Junior Einsteins Science Club, the philosophy is to teach children “how to think, not what to think,” helping prepare them for whatever challenges the future holds.
Working through challenges is a valuable part of teamwork, confidence-building and communication. It’s worth reminding kids that mistakes aren’t a bad thing — some of the best scientific discoveries have come from a “mistake”!
You may also enjoy reading: How to Get Slime off Carpets, Clothes, Sofa and Hair!
Did you know you can book Junior Einsteins Science Club for parties and events, after-school classes, and fun science holiday camps?
Frequently Asked Questions
Is this slime recipe safe for young children?
Yes — this recipe uses just cornflour and water, so it’s a good option for younger children or anyone who prefers to avoid glue- or borax-based slime recipes. As with any messy play, adult supervision is recommended, especially with toddlers who may put things in their mouths.
Why does the slime feel hard when I punch it but soft when I stir it slowly?
This is because cornflour slime is a non-Newtonian fluid. Fast force (like a punch) causes the tiny particles to jam together and resist movement, while slow, gentle movement lets the particles flow past each other like a liquid.
How long does homemade cornflour slime last?
Cornflour and water slime is best played with fresh, on the day you make it, as it will dry out and separate over time. It’s quick and inexpensive to make again whenever you fancy some hands-on science play.
What age is this activity suitable for?
This is a flexible activity that works well from toddler age right up through primary school, with adult supervision for younger children. Older kids will enjoy exploring the science explanation in more depth.
Related Articles
- Hands On Science for Your “Junior Einsteins” Parties, Camps and Classes and Events
- Watch Out! Some Slime for Kids Contains Dangerous Levels of Boron
- How to Get Slime off Carpets, Clothes, Sofa and Hair!
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