Watch colors burst, swirl, and sink through water like tiny fireworks.
This simple science activity is an experiment kids instantly want to do again. The colors move slowly through the jar, stretch into the water, and then run in every direction as the oil and water separate.
It feels magical.
But underneath all of that movement, kids are also exploring liquid density, color mixing, and how oil and water react differently.
If you are exploring density activities with kids, be sure to visit our Oil & Water Experiments for Kids guide. This fireworks experiment is one of our favorite ways to see density science in action.
This experiment is simple to set up, visually exciting, and great for:
- science fair projects
- summer STEM activities
- classroom science
- easy kitchen science
- rainy day learning
The best part is watching the food coloring suddenly break through the oil and explode into the water below.
How to Make Fireworks in a Jar
Supplies
You only need a few simple materials:
- Clear glass jar
- Water
- Vegetable oil
- Food coloring
- Small bowl
- Spoon
- Paper towels
Step 1: Fill the Jar with Water
Fill a clear jar about 3/4 of the way with water.
Set the jar aside while you prepare the oil and food coloring mixture.
Step 2: Prepare the Oil and Food Coloring
Pour about 3 to 4 tablespoons of vegetable oil into a small bowl.
Add several drops of food coloring. We used multiple colors to create a brighter fireworks effect.
The food coloring will sit in the oil rather than mixing into it.
This simple setup creates the same kind of fascinating oil and water separation kids explore in our Lava Lamp Sensory Bags, where oil and water separate in fascinating ways.
Step 3: Stir the Mixture
Use a spoon to gently stir the oil and food coloring together.
The colors will break apart into smaller droplets, which helps create the fireworks effect once added to the water.
Kids love this step because the colors already begin to twist and turn through the oil.
If your kids enjoy watching colors move and separate like this, they would also love our Glowing Oil & Water Experiment.
Step 4: Pour the Oil into the Water
Slowly pour the oil mixture into the jar of water.
At first, the oil will float at the top.
Then the food coloring begins to drift down through the water in colorful ribbons.
The slow movement almost looks like colorful storms forming inside the jar, similar to our Tornado in a Jar experiment.
Step 5: Watch the Fireworks Form
Within moments, the food coloring begins to fall through the oil and spread into the water below.
The colors stretch downward like tiny fireworks exploding underwater.
Some colors drift slowly.
Some burst outward immediately.
Some twist together as they sink.
This is the moment kids always react to.
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Kids are always fascinated by the way the colors drift and twist through the water. Our Glowing Fireworks in a Jar experiment creates an even brighter version of the same reaction.
Why This Experiment Works
This activity demonstrates how different liquids interact based on density. The oil floats because it is less dense than water.
Food coloring is water based, so it does not mix with the oil. Instead, the droplets eventually fall through the oil layer and dissolve into the water below.
Kids can actually watch the liquids separate in real time, which makes the science much easier to understand. If your kids enjoyed this activity, they would also love our Homemade Lava Lamp Experiment.
That movement creates the fireworks effect.
This experiment is a fantastic visual way to introduce:
- density
- oil and water separation
- liquid behavior
- color mixing
- scientific observation
Watching the colors slowly spread through the water is one of the reasons kids love density science so much.
Tips for the Best Results
- Use a clear jar so kids can easily watch the colors move.
- Liquid food coloring works best for this experiment.
- Stir gently so the droplets stay separated.
- Try different color combinations for different effects.
- Perform the activity near a bright window for maximum color visibility.
Science Fair Project Idea
This activity also works really well as a simple science fair project.
Kids can test:
- different types of oil
- warm versus cold water
- gel food coloring versus liquid
- how droplet size changes the movement
The visual results make this an especially engaging project for elementary-aged kids.
Explore More Oil & Water Science
If your kids loved this activity, continue exploring density science with these related experiments:
These activities all help support early science learning while still feeling playful and hands-on.
Final Thoughts
This fireworks in a jar experiment is simple, colorful, and incredibly fun to watch.
Even though the setup only takes a few minutes, the results feel dramatic every single time.
It is one of our favorite ways to explore density concepts, because the reaction is easy to see from the very first moment the colors begin to fall.
📌 Save the fireworks in a jar experiment for later and explore more colorful oil and water science activities with your kids!
