If you’re looking for fun and easy science experiments, look no further! We have loads of easy science guides for you, including this one – Magic Milk Science Experiment, a swirling, colourful science experiment that you can do right now with things from your kitchen!
Magic Milk Science Experiment is a classic science experiment and a great opportunity to learn hands on. You’ll need to grab some basic supplies and our video and tutorial below guide you through what to do. As you and your budding scientist play, talk about the colours and patterns being formed as the milk swirls around, and explain the science behind why the milk moves (the science-y bit is below).
The beautiful rainbow colours in the Magic Milk Science Experiment create a marbling effect.
- Full fat milk (must be full fat)
- A plate or shallow tray
- Colouring – various. You can use standard food colouring but we found the liquid colouring we use to make bath bombs produced the most stunning results.
- Cotton buds
- Washing up liquid
Pour a thin layer of milk onto the plate to cover the bottom, only a few millimetres deep.
Drop colouring of your choice onto the milk. You can add loads like we did, or just a few drops.
Try not to move the plate other wise the colours might start mixing.
Add a drop of washing up liquid to the end of a cotton bud.
Press the cotton bud into one of the colours and hold it there for a while. The milk should move away from the bud and the colours should start swirling.
Press the bud into another drop of colour and watch the colours move.
Refresh your bud with washing up liquid and choose another colour to play with.
You can choose to press into a colour for a long time or experiment with pressing quickly into different colours to create different effects.
Continue until the milk stops moving or the colours have mixed enough.
When you have finished, dispose of the magic milk by washing down the sink with water.
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Here’s a close up of the swirling rainbow effect we got:
The science bit!
There’s quite a lot of science going on in the Magic Milk Science Experiment. It can be used to introduce new terms such as hydrophobic, hydrophilic, molecules, micelles and diffusion
Why does the detergent make the milk move?
Milk is made up of water, proteins, minerals and fats. Fats don’t mix with water, they are called hydrophobic (“water hating”). The fat in the milk doesn’t mix with the water in the milk, nor does it mix with the water based colours; hence at the start of the experiment the colours stayed in droplets and didn’t blend into the milk.
Detergent breaks fats into very tiny fat spheres called micelles. These have a special shape which enables them to mix with water. Think of micelles as tiny fat spheres that are no longer hydrophobic. This is why you use detergent for washing up – it breaks the fat up which can then easily be washed away.
So, when you add the detergent to the milk, you turn the milk’s fat molecules into micelles which mix with the water in the milk. The reason you get swirling effect is because the fat globules are trying to stay together, but the detergent is trying to break them apart. There is a battle going on between them and the molecules are racing around.
During all this the food colouring is bumped into and dragged around with the racing fat and detergent molecules, so you see a beautiful rainbow swirling effect.
Eventually the washing up liquid becomes evenly mixed with the milk – the milk fats have turned into micelles and the swirling slows and eventually stops. This is why full fat milk works best, it produces a longer lasting battle with the detergent, creating a kaleidoscope of colours.
Want more easy science?
If you try these activities at home you do so at your own risk.
Grab one of our science kits so you don’t have to gather all the materials needed, check them out here.
Looking for more easy science ideas? Well head on over to our blog to find out other cool experiments such as Glowing Fluorescent Liquid or the Super Easy 6 – a free download with 6 super-easy experiments to try at home!