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Learn how to create a colorful and exciting Fourth of July fireworks in a jar with just a few simple ingredients. This science experiment is perfect for kids. It will teach them about density and chemical reactions between different liquids. And it’s not just for the 4th of July! It can be used any time of year.
Also check out this Liquid Density Experiment for Kids! It’s another cool way to demonstrate varying liquid densities.
What Are Fireworks in a Jar?
These homemade Fireworks in a Jar are far from real fireworks. There are no loud noises or fire. However it is still a celebration! They are a cool way to demonstrate some physics and chemistry concepts for Independence Day.
Who says educational activities are just for school days? You may remember this activity from your childhood since it is a great classic. I would say this activity could easily be done with very little adult supervision.
Supplies Needed
To make the Fireworks in a Jar activity, you just need a few basic supplies. All of these things will be found in your home or at the grocery store.
Instructions to Make Fireworks in a Jar
- Fill the Jar with Warm Water: Pour warm water into a clear large jar or a tall glass until it’s about three-quarters full.
- Prepare the Oil and Food Coloring Mixture: In a small bowl, combine 3-4 tablespoons of vegetable oil with several drops of food coloring. A little less color is better than more. About 4 drops of each color worked best when we tried it. You can use multiple colors for a more interesting effect. Use a fork or spoon to gently stir the oil and food coloring. Try not to let it settle to the bottom of the bowl because it will stick as you pour it. The food coloring will separate into small droplets that are suspended in the oil.
- Combine the Mixtures: Slowly pour the oil and food coloring mixture into the jar of water. Slowly is the key here. If you go too quickly, the coloring will go straight into the water. You want it to stay in the oil as you pour for the best result.
- Watch the Reaction: Watch as the food coloring droplets start to sink through the oil and then disperse into the water, creating the look of fireworks. The color seeps fairly quickly, so be sure to watch it so you don’t miss the fun swirls!
The Science Behind It:
Use my Scientific Method Worksheets to turn this into a more formal lesson.
Density Difference: Oil is less dense than water. Since they are different weights, it floats on top of the water.
Immiscibility: Oil and water do not mix, and the food coloring is water-based, so it doesn’t dissolve in the oil. Oil is called hydrophobic, or water-fearing.
Water (H20) is made from two hydrogen atoms and one oxygen atom. Water molecules are polar, meaning they have a partial negative charge from the oxygen and a partial positive charge from the hydrogen. This causes the water molecules to be attracted to each other.
Oil, on the other hand, is made up of hydrogen atoms and carbon atoms so they are called hydrocarbons. They are non-polar, meaning the electrons are evenly distributed across the molecules with no negative or positive charge. These bonds are not strong enough to break the strong hydrogen bonds that hold the water molecules together, so they cannot mix.
Color Dispersion: When the food coloring droplets sink through the oil and hit the water, they start to dissolve, creating the “fireworks” effect. Color will disperse more quickly in warm water versus cold water. This is why it is important to use warm water.
Variations on the Fireworks In a Jar Experiment:
Ice Cube Fireworks. Freeze cubes of colored water. Fill the jar with warm water, add a layer of oil, then add the colored ice cubes.
We loved this one even better than the original because the reaction lasted much longer!
We used yellow and blue for this one and it mixed so nicely! I made the star ice cubes with a star-shaped silicone mold.
Baking Soda and Vinegar Fireworks: Fill the jar halfway with warm water and mix in a spoonful of baking soda. Add a layer of vegetable oil. In a small bowl, mix food coloring with vinegar. Pour the vinegar and food coloring mixture into the jar. This one didn’t have the same swirling color reaction, but it was fun to watch the bubbling with the baking soda and vinegar as it reacted.
Glitter Fireworks: Make it the same but add glitter to the oil and food coloring mixture.
Salt Fireworks: Sprinkle salt into the oil and food coloring mixture before adding it into the water. Salt is more dense than oil, so it sinks, carrying the droplets of oil and food coloring with it. When the salt dissolves in the water, the oil and food coloring bubble back to the surface .
This experiment demonstrates some important scientific principles. But, it also captures children’s attention with the colorful display. It is a perfect addition to your homeschool or school lessons.
See More of the Best Kids Activities for Teaching:
Rainbow Science: Sugar Density Experiment
Sink or Float: Density of Salt Water
Fun Printable Summer Mad Libs for Kids
How to Make a Five Pointed Star or Origami Star
The COOLEST Science Art Projects for Kids
