milk experiment


Experimenting colours with toddlers is such a fun, quick, budget-friendly activity to try. It’s simply 3 ingredients and takes 2 minutes to set up.

Purposeful Play: Why do toddlers need to be shown experiments? It’s all to do with how we process information. The Prefrontal Cortex at the top of the brain is responsible for developing higher order thinking skills, cognitive function, decision making etc. Thoughts such as scientific reasoning and cause and effect are created here.

It’s important to note that as you model this experiment make sure you’re using language skills to build purposeful play. See our explanation on information processing. What I mean is talk to your child about what’s going on as you are doing these steps. Conversation creates communicative language and early social skills.

What you need is:

A tray, a cup of milk, 3 different food colouring, detergent and a cotton bud for each person.

Step 1: Pour a cup of milk into your tray. It should just cover the whole bottom of the tray so if it doesn’t pour a little more.

Step 2: Use one food colouring at a time, pour a little bit into the lid. Discuss what colour you’re pouring with your child. Then use the lid to dot colour around the tray. Repeat ‘dotting’ with other colours.

Step 3: Pour detergent onto your cotton bud.

Step 4: Ready? Place your cotton ready to hold into the middle of the milk tray for best results.

See how we did our milk experiment.

Step 5: Talk to you child about what is happening (cause and effect). What did it look like before? And, what does it look like now? Try using descriptive words repeated 3 times for speech development: like ‘mix mix mix,’ or ‘swirling, swirling, swirling.’

Step 6: You can reuse your cotton bud in milk to a certain point but then you can restart the whole experiment again.


It comes down to early chemistry and surface tension. The detergent is a surfactant. As it spreads over the milk it creates surface tension and pulls the food colouring with it.

Be present and in the moment with your child/ren during this experiment. Answer toddler questions about WHY the colours mixed.

By Sarah Courtney

Mum of 3, Wife, Early Childhood Teacher, and Blogger.


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