Water Fireworks: Create Stunning Colour Explosions Using Expired Milk
Why This Experiment Is So Popular
Got expired milk in your fridge? Don’t dump it—turn it into a colourful science show!
This activity transforms kitchen scraps and simple tools into a stunning display of swirling colours, much like fireworks in water. Kids not only get to watch colour “explode,” but also understand how detergent affects surface tension. It’s part science, part art, and 100% fun.
What’s the Science?
Milk contains fat and protein. When dishwashing liquid touches the surface, it breaks the surface tension and starts reacting with the fat molecules. This motion causes coloured water-based marker ink to be pushed and pulled—resulting in beautiful bursts and ripples of colour.
Materials You’ll Need
| Item | Details & Tips |
|---|---|
| Expired milk | Room temperature is best (cold milk slows the reaction) |
| Clean face towel or thick tissue | Foldable, white/neutral colour to show ink clearly |
| Water-based markers | Any bright colours (avoid permanent markers) |
| A bowl or wide container | Transparent if possible (glass or plastic) |
| Scissors | Use child-safe scissors for younger kids |
| Dishwashing liquid | Any household brand works (e.g. Morning Fresh) |
| Cotton swab or teaspoon | For adding detergent in a controlled way |
Step-by-Step Instructions
1. Prepare the Paper Base
- Take a clean white face towel or thick disposable tissue.
- Fold it neatly in half to make a rectangle.
- Use a pencil or marker to draw a circle in the middle of the folded towel.
- Carefully cut around the circle while the towel is still folded. Once opened, it should have a clean circle hole in the middle.
2. Decorate with Marker Colours
- Lay the unfolded towel flat on a clean surface.
- Around the edges of the circle hole, use water-based markers to draw thick dots, curved lines, or spiral shapes.
- Encourage kids to use contrasting colours—blue and red, green and orange—for more dramatic swirls.
3. Fill the Bowl
- Pour expired milk into a clear bowl until it’s about 2–3 cm deep—just enough to submerge the towel completely.
- Let the milk settle. If it’s curdled, skim off the solid bits or switch to another portion.
4. Add the Towel
- Slowly place the decorated towel into the milk, coloured side facing up.
- Ensure the towel lays flat and fully soaked—no bubbles or dry patches.
5. Add the Dishwashing Liquid
- Dip a cotton swab into dishwashing liquid, or use a teaspoon.
- Carefully drip 1–2 drops of detergent directly into the centre of the hole in the towel.
- Wait just 2–3 seconds… and watch the colours erupt outward!
What You’ll Observe
- Colours will begin to move, swirl, and shoot outward from the hole.
- Some ink will twist into spirals, others will fan out like petals or fireworks.
- Over time, the colours will soften, blend, and become a marbled display.
Fun Variations to Try
| Variation | What to Do | Result |
|---|---|---|
| Mini Fireworks | Cut smaller holes in the towel | Multiple bursts from different zones |
| Star Cut-Out | Cut a star instead of a circle | Unique firework patterns |
| Speed Test | Try warm milk vs cold milk | Warm milk reacts faster |
| Compare Detergents | Use different brands of dishwashing liquid | Some will create faster or larger reactions |
Questions to Ask Kids
- What do you think caused the colour to move?
- What happened when we added more detergent?
- Did all colours behave the same way?
- What would happen if we used juice or water instead of milk?
These questions prompt children to observe carefully, make predictions, and explain cause-and-effect relationships—just like real scientists.
Tips for Teachers & Parents
- Prepare extra pre-folded towels for group use.
- Run this activity near a window for natural light to enhance the visuals.
- Place a dark-coloured tray under the bowl to increase contrast.
Cleanup Tip: When finished, discard the milk in compost or carefully pour it into the garden (non-toxic and nutrient-rich). Rinse the bowl and towel immediately to prevent stains.
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Final Words
Don’t throw out that expired milk just yet—it might be your next science masterpiece. Water Fireworks is a brilliant blend of chemistry and creativity, with vivid colours and real wow-factor. Whether you’re homeschooling, running a classroom lab, or just entertaining on a rainy afternoon, this activity delivers explosive engagement.
Want more creative experiments like this? Browse our Kitchen Science Lab for more DIY magic!
