Looking for a simple, mess-free activity to keep the kids entertained while waiting for the real fireworks? This Fireworks in a Jar science experiment is the perfect way to bring a little spark to your celebration! Using basic kitchen ingredients, your kids can create a colorful explosion right in a jar — no loud booms or cleanup required.

I actually tested this out over the weekend with my two boys (ages 3 and 5), and they were mesmerized. They loved watching the colors swirl and mix, and it was a fun way for us to sneak in a little science before dinner. It’s a quick activity with a big “wow” factor—and best of all, it only takes a few minutes to set up.

It’s quick, fun, and perfect for kids of all ages.

What You’ll Need:

1 clear glass jar or cup
Water
4 tablespoons of vegetable oil
Food coloring (any colors you like)
A small bowl
A fork

Step-by-Step Instructions:

1. Fill the jar about ¾ full with water and set it aside.

2. In a separate bowl, add 4 tablespoons of oil. Then drop in a few drops of food coloring—about four drops per color works great.

3. Mix gently with a fork. You’ll see the food coloring separate into small drops within the oil.

4. Slowly pour the oil and food coloring mixture into the jar of water.

5. Watch the magic! The colored droplets will sink through the oil and burst into the water below, spreading out like little fireworks.

Check This Video From Twinkl to see it live in action!

Why It Works:

This mini experiment is a great introduction to liquid density and solubility. Oil floats on water because it's less dense, and food coloring (which is water-based) sinks through the oil. Once the drops hit the water, they dissolve and expand, creating bursts of color.

It’s science you can see — and your kids will love it.

Tips for Best Results:

Try using a tall, clear jar for a bigger visual effect.
Red, white, and blue food coloring makes it extra festive for the Fourth!
For younger kids, use a spoon to pour the mixture slowly and avoid spills.
Make sure your water is room temperature for the best reaction.

This easy activity is a great conversation starter about how different liquids interact. It’s also a nice quiet moment before the louder fireworks start—and a way to bring some colorful joy indoors, especially if it’s too hot outside!