Pinbusted or Pintrusted: Fireworks in a Jar

GeekMom PinBusted or PinTrusted


This one comes straight from a Pinterest link to About a Mom’s post on Science Fun for Kids. I’d grabbed the pin because of the pretty picture and the simple ingredients list:

  • Warm Water
  • Vegetable Oil
  • Food Coloring

The instructions read:

Fill your jar with warm water.

In a separate bowl, mix 3 – 4 tablespoons of oil and several drops of different colors of food coloring. We used red, blue, yellow, and green. Use a fork to gently mix the oil and food coloring together.

Pour the oil mixture into the jar of warm water.

So when I found myself with an hour to kill after dinner, alone with the 2.5 year old toddler, I decided to give it a try. I took the oil, several drops each of the four colors of food coloring, and water that was near boiling. I poured the oil into the water–and got an instant jar of black ink.

Photo: Karen Burnham

Whoops! I decided that the water I’d used was too hot, and maybe I used too much food coloring.

Try #2: warm water from the tap into the jar, three colors of food coloring with two-three drops each in the oil. Same result: instant kraken-like jet black ink mixture.

I was about to call it quits (the toddler had turned to my iPad by now, although each iteration only took a few minutes), but as I was putting ingredients away I took one last look at the instructions (thinking that maybe a different kind of oil would work better)–“Use a fork to gently mix the oil and food coloring together.” Oh. I’d been skipping that bit. So I hauled everything out again, and here’s what worked:

Photo: Karen Burnham

Take 3 Tbsp of oil (any kind of vegetable oil will do). Add just two or three drops each of each drop of food coloring that you want. At first these will make big coherent drops in the oil, sort of like a lava lamp. (The science behind this experiment is that the food coloring is not soluble in oil, but it is soluble in water).

Photo: Karen Burnham

You want to break these big drops up by using a fork to stir.

Photo: Karen Burnham

Now pour the oil slowly into a jar 3/4 full of warm water, which can be from the tap. Now the oil will sit on top of the water and the small drops will float gently down to mix in the water–then you get your fireworks display.

Photo: Karen Burnham

By initially using drops that were too big, they all dropped to the bottom and into the water immediately, causing the entire reaction to happen in less than a second. With smaller drops they descend more gradually, prolonging the display into something you can see for (in my case) 20-40 seconds.

I did manage to recapture my toddler’s attention briefly to see the colors, but then he knocked over his water cup. After rescuing my iPad and mopping up the spill, the jar was back to its black, inky state. But I did manage to capture the “fireworks!”

The moral of the story Is: follow the instructions. All of them. Then it’ll work.

I will try this again when the wee one is a little older, and see if he’s more interested in it when it works the first time!

Liked it? Take a second to support GeekMom and GeekDad on Patreon!
Become a patron at Patreon!