Blast Off! A chemical reaction rocket

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If your child likes the excitement of a rocket blasting off, they will LOVE this STEM experiment!

The Blast Off Chemical Reaction Rocket experiment uses the power of a chemical reaction to build pressure inside of a bottle to shoot into the sky. It’s an experiment showcasing how chemical reactions work and an opportunity to show how rockets launch into space.

So head outdoors and let’s launch a rocket!

How to make the Blast Off Chemical Reaction Rocket STEM experiment

Supplies you will need

For this experiment, you’ll need:

2 liter bottle (empty)
Vinegar
Baking soda
Cork (this pack of assorted sizes will ensure you have the right size)
Popsicle sticks
Hot glue gun or a rubber band
Duct tape
Optional: funnel

Supplies needed for the Blast Off Chemical Reaction Rocket STEM experiment

Before you start

The rocket is fast, so be sure to step away from it when the reaction begins. This is also very messy and can shoot up high, so please do this outdoors.

Instructions

Here is how to do this experiment with your child:

Step 1: Attach the popsicle sticks to the bottle

Hot glue two sticks together to make a longer popsicle stick

Add some hot glue to the last inch of one popsicle stick, then place a new popsicle stick over the hot glue, overlapping them about 1″. Squeeze them together to form a solid bond. Repeat until you have three long popsicle stick legs.

Duct tape the three long popsicle stick legs equidistant from one another around the top of the 2-liter bottle. They should extend at least a few inches past the bottle opening so the bottle is off the ground.

Ensure that the bottle is level and stays upright with the popsicle sticks before moving on to the next step.

Adhering the popsicle sticks to the empty 2-bottle with duct tape, ensuring the sticks are longer than the bottle

Step 2: Add baking soda to the bottle

We added enough baking soda to cover the bottom of the 2-liter bottle, plus about a half inch more.

Step 3: Add vinegar to the bottle and quickly seal

Add about a cup of vinegar to the bottom and quickly place the cork in. Turn the bottle upside down so it is standing on the popsicle sticks.

Run!

The STEM behind the Blast Off Chemical Reaction Rocket experiment

This experiment teaches:

Chemical reactions
Propulsion
Designing a rocket

How it works

Baking soda and vinegar, when combined together, produce water, sodium acetate (a salt), and carbon dioxide gas. The more baking soda and vinegar we use, the more it produces in the process.

In the Chemical Reaction Rocket experiment, we create this reaction in a closed container (the soda bottle). As the amount of carbon dioxide builds up, so does the pressure inside of the bottle, until the bottle can no longer hold the pressure.

The cork (or whatever is used to contain the reaction) pops out and the rocket blasts off!

Chemical reactions

This experiment demonstrates one of the classics: the vinegar and baking soda chemical reaction!

The sodium bicarbonate (baking soda) and weak acetic acid in vinegar react and trap the carbon dioxide to form bubbles.

This reaction forms a significant amount of carbon dioxide gas and builds pressure inside of the soda bottle until it cannot be contained any longer.

Propulsion

The rushing air creates a force called thrust, which propels the rocket forward. This creates a concentrated stream of air molecules moving rapidly in one direction.

This is how thrust works with a rocket taking off into space as well!

Instead of a soda bottle, rockets use a combustion chamber to create the thrust needed to launch into space. The combustion chamber houses liquid fuel (fuel and an oxidizer), pumps, a nozzle, and plumbing.

During launch, the fuel and oxidizer are mixed. This mixture produces hot exhaust that is passed through the nozzle to accelerate the flow and produce thrust.

The gasses expanding inside the combustion chamber and nozzle are pushing outward in all directions. Since the nozzle is open on one end, those gasses can only push against the engine in one direction.

Using Newton’s third law of motion, as the gasses push down through the nozzle, the rocket shoots up!

Designing a rocket

This experiment gives kids the opportunity to design a simple rocket, complete with a body and combustion chamber (the soda bottle), rocket fuel (vinegar and baking soda), and a launch tower (the sticks).

They can also add decorations to the rocket, like painting the bottle or adding plastic fins (they’ll get wet!).