3-2-1 blast off! What can you do with a balloon and a straw? Build a balloon rocket, of course! Kids will love this awesome physics experiment that is more like play than science. A fun introduction to Newton’s Laws of Motion. We love hands-on and easy physics activities for kids!



This simple balloon rocket activity lets your kids think about forces in motion. STEM for kids doesn’t need to be complicated or expensive.

Some of the best STEM activities are also the cheapest! Keep it fun and playful, and not make it too difficult that it takes forever to complete.

This easy balloon rocket STEM activity can teach kids how the force of air moving in one direction can propel a balloon in the opposite direction, much like a real rocket! You can easily add in Newton’s Third Law as part of the science lesson!

MUST TRY: Have you ever made a bottle rocket for the outdoors?

Take up the challenge to make a balloon rocket with our step-by-step instructions below. Find out what makes the balloon move along the string and see how far or fast you can get your own balloon rocket to travel.

Also try these fun balloon rocket variations…


Let’s start with thrust. First, you blow up the balloon, filling it with gas. When you release the balloon the air or gas escapes creating a forward motion called thrust! Thrust is a pushing force created by the energy released from the balloon.

Also learn how the force of lift works with this paper helicopter activity!


Then, you can bring in Sir Isaac Newton and his third law. For every action, there is an equal and opposite reaction. This is the third law of motion. When the gas is forced out of the balloon, it is pushed back against the air outside the balloon, propelling it forward on the string!

Newton’s first law states that an object at rest stays at rest until an outside force acts upon it. An object in motion will stay in motion in a straight line until an unbalanced force acts upon it (think of a toy car going down a ramp).

His second law states that force times mass equals acceleration. All three laws of motion can be observed with a balloon rocket!



Turn it into a balloon rocket experiment by exploring what happens when the balloon is blown up to different sizes. Does the balloon travel further as it has more air in it? Learn more about the scientific method for kids!

If you want to set up an experiment that includes several trials with the same balloon, make sure to use a soft tape measure to measure the circumference of the first balloon. To recreate accurate trials, you need to change the independent variable and measure the dependent variable.

You can also get kids started by writing down their hypotheses before diving into the experiment. What do they think will happen when the blown-up balloon is released?

After performing the experiment, kids can draw conclusions as to what happened and how it matched their initial hypotheses. You can always change a hypothesis upon testing your theory!


  • Rocket Printout
  • Balloon
  • Tape
  • Drinking Straws (paper or plastic, which one works better?)
  • String (yarn or twine, which one works better?)
  • A clothespin (optional)
  • Scissors


STEP 1: Locate two anchor points across the room from each other like two chairs. Tie off one end of the string.

STEP 2: Thread the straw onto the other end of the string before tying off that end on the 2nd anchor point. Make sure the string is taught.

STEP 3: Cut out our rocket or draw your own. You could even use a sharpie to draw one on the side of the balloon.

STEP 4: Blow up the balloon and secure the end with a clothespin if desired or hold it. Tape your paper rocket to the balloon.

STEP 5: Tape the balloon to the straw.

STEP 6: Release the balloon and watch your rocket take off! This is one you will want to repeat again and again!


Once you do the initial balloon rocket experiment, play around with these questions and see what you come up with for answers!

  • Does a different shape balloon affect how the rocket travels?
  • Does a different type of string affect how the rocket travels?
  • Does the length or type of straw affect how the rocket travels?


Want to turn this balloon rocket into a cool balloon rocket science project? Check out these helpful resources below.

You can also easily turn your trials into a fantastic presentation along with your hypothesis. Add extra trials using the questions above for a more in-depth science fair project.


Also, try one of these easy engineering projects below.

Learn about how lift works with this paper helicopter activity.

Build your own mini hovercraft that actually hovers.

Build a balloon powered car and see how far it can go.

Design an airplane launcher to catapult your paper planes.

A good breeze and a few materials are all you need to tackle this DIY kite project.

It’s a fun chemical reaction that makes this bottle rocket take off.

Click on the image below or on the link for more easy STEM projects for kids.