rocket science project hypothesis

Learn STEM by Doing (and having fun)!

Science Fair Project: Alka-Seltzer Rocket Showdown

It was a warm, sunny afternoon, when they crept inside…  Mom!  We’re boooored!  I wanted to avoid the iPods or Netflix, so I scraped together supplies to make homemade baking soda/vinegar rockets to shoot off in the backyard.  Holy cow!  Lots of rocket FAILS that day!   I may still stink like vinegar…   After working through different materials, we came up with our favorite combination and the kids learned more about acid/base reactions.  In this post, we walk through how our kids learned how to build an Alka-Seltzer rocket.  What’s also great about this project is that it can be easily turned into a science fair project… let’s SCIENCE!!

SHORT VERSION OF THE EXPERIMENT (tl;dr) :  your kiddos will learn how to make a rocket using an empty 35mm film canister  “powered” by Alka-Seltzer and water.  Not a rocket scientist?  NO PROBLEM!  You can pull this off with most of the items already in your house, a trip to the dollar store, or of course, Amazon.  The experiment is probably best suited for 3rd graders and up, and beyond the basics of experimental design, they will learn about chemistry (acid/base reactions), physics (propulsion, motion), and the scientific method.  Basic data analysis (counting, comparing) can be used and if you snap some pictures along the way, during the construction and “launch”, setting up a science fair project board can be done in super easy fashion (like a single day)!

Edit: We recently learned a team at the University of Minnesota broke a Guinness World Record by blasting an Alka-Seltzer powered rocket 430 feet high!!! Whoa!!

Science fair project overview:  what we’ll do

Build an alka-seltzer rocket.

Hey STEMium readers!  In this project, you’ll be comparing different “rocket fuel” combinations for our homemade rockets to see which one flies the highest.  You will construct your rocket out of an empty 35mm film canister, paper/cardboard and other accessories as needed (who DOESN’T want a glitter fin??).  Then, you’ll use different ratios of our “rocket fuel” mix:  Alka-Seltzer in water.  Some rockets will get a lot of Alka-Seltzer.  Others will only get a little Alka-Seltzer, so we can see if more means a bigger liftoff.  Get ready to get messy as this one may leave some spills.  If you’re going to do it indoors ( not recommended ), you’ll need a tarp, really high ceilings (like in a gym) and possibly a mop/cleanup crew.

Who can do this project?  Age range: 3rd Grade and up

We first did this experiment with a 2 nd grader, a kindergartner, and a preschooler.  Later, we turned it into one experiment center at a science night out for 3rd-6th graders.  Looking at all the grade settings, I think the concepts were a bit more challenging to convey to the younger groups (although they definitely enjoy the launches!).  It would probably be better suited for older kids – 3 rd grade and beyond.  Younger kids can still participate and help design/build the rockets.

The Science Behind The Alka-Seltzer Rocket

Before we delve into the details of the experiment, let’s talk more about how we’ll get our rocket to blast off.  There is so much science goodness packed into these experiments it’s hard not to get too excited!!

The chemistry of alka-seltzer

We will be taking advantage of ACID/BASE reactions.  Specifically, our rocket fuel of choice will be a combination of Alka-Seltzer and water.  While we’ve experimented extensively with baking soda and vinegar, the bottles and general setup is a little more hit or miss (and waaaaay messier).  I’ll put some links in the appendix if you’d like to try to compare “rocket fuels”, but for now we will stick with building an Alka-Seltzer rocket.

A chemical reaction is occurring whether you use baking soda/vinegar or Alka-Seltzer/water — an acid and base reaction, to be exact.  There’s some great background info from Khan Academy on acids/bases for more info, but the simplest explanation is that ACIDS are materials that have a lot of hydrogen ions (H+)…  When an acid is combined with a BASE (a substance with a lot of hydroxide ions, OH-), we call this an acid/base reaction and the end result is usually the generation of a salt and water (and especially important in our case — carbon dioxide gas!).

Mixing acids and bases – how does alka-seltzer work?

As you can see from this picture, when you open the Alka-Seltzer package, it looks like a simple tablet.  Digging deeper, Alka-Seltzer is a combo product, meaning it contains both an ACID (anhydrous citric acid) and a BASE (sodium bicarbonate).  The “anhydrous” part means that it has no water…hence, why it’s individually packaged to keep moisture out.  When you drop the tablet into a glass of water, the acid/base reaction can begin as the two reagents (citric acid and sodium bicarbonate) come together.  The picture below shows what’s going on in the chemical reaction… by combining this acid and base, we create water, a salt (sodium citrate) and carbon dioxide (CO 2 ).

How Does The Rocket Take Off?

Back in 1686, Sir Isaac Newton formalized the key laws of motion… Newton’s third law is directly evaluated in our Alka-Seltzer rocket experiment:

<<For every action, there is an equal and opposite reaction>>

Check out this video below from Khan Academy for a good breakdown on Newton’s laws:

At this point you might be asking:  What does this mean and what does it have to do with bottle rockets??   Well, when the CO 2  pushes out of the rocket, the rocket pushes away from the gas.  Gravity is another force pulling the rocket, keeping it on the Earth, but when the force of the gas pushing the rocket becomes greater than gravity, the rocket lifts off.

Also keep in mind: SAFETY FIRST !  These are not space shuttle-like explosions, but there will be liquid spilling out quickly and broadly.  Assuming things are assembled properly, your rocket will blast off.  Wear eye protection if appropriate and do NOT aim the rocket at anyone or anything.

Materials – what you’ll need:

• Alka-Seltzer tablets – pop, pop, fizz, fizz . You are looking for the original effervescent tablets that fizz when dropped in water.  Not the chews.  Not the flavored kind.  You can try this link here .  We did not try Alka Seltzer Gold in our rockets, which contains two antacids (sodium citrate, potassium citrate) instead of just the one; however, I think it would most likely work the same.  Store brand product would also likely work out well.  Ideally, you want fresh material versus something that’s been sitting in a medicine cabinet for the last few decades.
• Water .   Just plain old water.  If you’ve got a tap (or bubbler as the fine folks of Milwaukee call it) then you are all set.
• Film canisters with lids – if you have some laying around the house, feel free to use any container that has a lid which will snap shut. If you’re like us though and haven’t used any film in the past decade, then cruise on over to Amazon.  We found this 12-pack of containers which should do the trick.  The seal that the lid makes with the container is important for the pressure to build up in the canister…so if you see people mentioning a flimsy lid, or poor seal in the reviews on Amazon, AVOID it and make a different selection.
• Construction paper/thin cardboard/index cards, scissors, markers/crayons, tape. The art supplies will be used to create the cone and fins on the rocket.  Get creative… if there are other lightweight materials that the kids are interested in adding (e.g. maybe glitter? Tinfoil?) go for it.
• Paper towel . Not necessary for the experiment but should make clean up a lot easier.
• Plastic drinking straws (optional) . We added these to our Alka-Seltzer rocket to work as a tripod landing gear — basically, the rocket stood on these three legs like a stool.  It just kept the bottom of the rocket (“top of the film canister”) off the ground at launch.  You can also use cardboard triangle cutouts to make fins.

Designing the Experiment:  Picking a Hypothesis

Like our other experiments, it all starts with selecting a hypothesis….  Remember, we will vary the amount of Alka Seltzer used in our rockets and compare which one blasts off the most.   What do we think will happen ?

Experimental Controls

This is a bit more challenging than our “ Germiest Spot in School ” experiment.  In that one, we had negative controls (bacterial plates with NO growth) and positive controls (bacterial plates with COMPLETE growth).  For our rocket experiment, one negative control might be a rocket with only water (but it’s kind of a bummer because it’s something that won’t fly).  Positive controls are a little trickier to come by though.

CHECKPOINT :  At this point, you should have a hypothesis about which rocket will fly higher, and why.  You may also have a few other variables you are testing… here’s what we wrote down:

• Hypothesis : the Alka-Seltzer rocket with a full tablet will fly further than the baking soda rocket
• Variable – Alka Seltzer : we made one rocket with a ¼ of a tablet, one rocket with a ½ of a tablet, one rocket with one full tablet, and one rocket with a tablet all ground up.
• Controls : you can do a negative one if you’d like.

Here’s our grid:

Methods/Procedure – How we’re going to complete our rocket build:

The steps listed below are how we completed our rocket project as an experiment; but please note, we did not enter this one as a science fair project.  You should be able to do this one as either approach — if you will be turning it into a science fair project, make sure you taking good notes and pictures to document everything.   In terms of how long it will take you, there’s about 15-30 minutes of setup/prep time (this is mostly designing the rocket — the creative part of the project), about 30 minutes for setting up reactions and launching rockets, and about 30 minutes to compare launches and analyze the data.  Assuming you have all the materials you need, you could get this one done in a single afternoon.

Time to build:  Alka-Seltzer rocket…

• Creative time! Decorate the rocket .  The opening of the film canister will serve as the bottom, so it will be firing with the lid end on the ground and the bottom end on top.  Cut enough construction paper to wrap around the film canister and decorate however you’d like.  Use the tape to stick onto the container.  Also create a rocket nose cone out of paper and tape to the “top” of the rocket (“bottom of the film container”).  If you’d like to create fins, you can also add those on.  You can also now fix on your rocket “legs” with the straws by taping three to the sides.  Make sure the rocket can stand upright and doesn’t tip over.
• Launch prep . Turn the rocket upside down to load the water in the container… fill it ~1/4 to ½ of the way full.  Make sure to note HOW MUCH water you added, so you have your combinations ready to test (look back at your chart if you need to keep track).
• LAUNCH ***need to move quickly here!*** . Break an Alka Seltzer tablet in half (or fourths or leave whole, depending on which tube you are loading) and add the tablet in the container with the water.  QUICKLY!  CLOSE THE CONTAINER – make sure to snap the lid on completely.  Set the rocket on the ground upright (lid side down at the ground).  Stand back and count down the launch.
• BOOM! Use a landmark or object to gauge how high the rocket made it.  Mark it down in a notebook or sheet of paper.  Also note how much “rocket fuel” was used – was it half a tablet and half full with water?

Data Analysis – What does the data tell us?

Congratulations!  You’ve officially built and launched rockets!

Hopefully, you’re not completely covered in a mess at this point and you have had some successful launches!  Which rocket flew the farthest?  Were any duds?  Was your original hypothesis correct?  How about testing the different variables – did adding more Alka-Seltzer to the rocket create a more powerful rocket?  If you did multiple rockets of the same kind (“replicates”), did they all fly the same or did some work better than others?

Your data analysis table might look something like this:

Conclusions – what we learned from the Alka-Seltzer rocket experiment; did it work?

Hopefully, the kiddos have a good idea about which rocket worked better or best. Hopefully, they also have a general understanding of what happens when you combine an acid and a base.  Most importantly, hopefully they had fun!!

Other things we’ve tried

After some fine tuning, we originally incorporated Alka-Seltzer rockets at a STEM outing and based it off of the Alka Seltzer science experiments site .  Overall, our rockets blasted off pretty easily with the majority successfully reaching some pretty good heights.

Now, separately, we have also tried the baking soda/vinegar rockets at home one summer day, but after getting drenched in about a gallon of vinegar we eventually abandoned our efforts that were based on this posting that we found using empty water bottles and a soda bottle .  While we had plenty of bottles, and we were even able to make the baking soda packets pretty easily, we struggled with corks that could fit tightly enough in the bottles.  The result:  tons of messy spills and leaks.  No takeoffs and bored kiddos.

While the baking soda/vinegar rockets will likely give you a bigger “boom”, they’re definitely more challenging to set up… from the starter perspective, if this is your first time, I’d opt for the Alka Seltzer/water setup in the film canisters to save your sanity.  Hands down – the Alka-Seltzer rocket strategy was far easier to maneuver and to keep the kids engaged.

Our results

As you can see from some of the pictures here, our Alka-Seltzer rocket with the most tablets flew the farthest.  As we increased the amount of Alka Seltzer in the container, we definitely noticed a stronger reaction taking place.  Interestingly, we couldn’t get much of a pop with the ground up tablet rocket.

Next steps – what are some follow up experiments?

There are a TON of different variables you can experiment with in the Alka-Seltzer rocket projects, which makes it fantastic to use for a science fair project.  Here are a few concepts/variables to further explore:

• Different solutions (besides water). What if you dissolved the Alka-Seltzer tablets in something besides water?  How would the reaction proceed if it were an acidic solution like orange juice? Vinegar?
• Different temperatures. What if you added ice, cold water to the container?  Would it change the intensity of the blastoff?  What about hot water?
• NASA – parts of a rocket
• https://media.nationalgeographic.org/assets/file/Seltzer_Rocket_Lab_Activity.pdf
• Check out the original Alka-Seltzer site to get great ideas and pics for not only the Alka-Seltzer rocket, but other Alka-Seltzer-based experiments:  https://www.alkaseltzer.com/science-experiments/

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Classroom Activity

Simple rocket science continued.

Balloon rocket materials and setup as described in Simple Rocket Science

Chart paper

Objects to use for nonstandard measurement (interlocking cubes of assorted colors, paper rockets , etc.) OR rulers for standard measurement

Journal OR piece of paper for each student

• This activity can be done as an extension of Simple Rocket Science .
• Set up the fishing line, straw and balloon as noted in Simple Rocket Science.

NASA uses rockets to launch satellites and probes into space. NASA rockets are powered by burning solid, liquid or gas rocket fuel.

Long before the development of modern rockets, Sir Isaac Newton described the principles of rocket science in three laws of motion.

A simplified explanation of his third law of motion helps young students understand how rockets work. This law states that every action has an equal and opposite reaction.

When a rocket expels fuel or propellant out of its engine, the rocket moves in the opposite direction. The rocket pushes the propellant out, and the propellant then pushes the rocket. The propellant comes out of the engine; this is the action. The rocket lifts off the launch pad in the opposite direction; this is the reaction.

In this activity, the rocket is a balloon propelled by air. The greater the propellant, the greater the action and thus, the greater the reaction. Students will experiment with different amounts of air and measure the distance the rocket travels.

Image credit: NASA/JPL-Caltech | + Expand image

Mark the location where the balloon came to a stop (circled). Image credit: NASA/JPL-Caltech | + Expand image

• Set up the experiment as described in Simple Rocket Science . Discuss with students what they learned from the experiment in Simple Rocket Science.
• Explain to students that in this lesson, the balloon experiment will also be repeated several times. Let students know there will be one difference in the experiment this time. Each time the class conducts the experiment, there will be a different amount of air in the balloon, and we will keep track of the results.
• Draw a vertical line on chart paper to create two columns. Label the two columns “Number of Breaths” and “Distance Traveled.” For non-readers, drawings may be more appropriate than words for the column titles.
• Blow up the balloon using one breath or stroke of the balloon pump.
• Place a “1” on the chart under “Number of Breaths.”
• Ask students to determine from where we should launch the balloon (far to one end of the fishing line). Mark the location of the front of the balloon on the floor to indicate the launch point.
• Launch the balloon.
• Once the balloon comes to a stop, mark the location of the front of the balloon on the floor.
• Have a student use interlocking cubes (or any nonstandard measurement device, such as one of these paper rockets ) or a ruler to measure how far the balloon traveled from its starting point. Remind students to use the unit of measurement when they talk about the distance traveled. For example, “The balloon traveled a distance of 17 cubes.”
• Record this measurement on the chart under “Distance Traveled.”
• Ask the students what they think will happen if we use two breaths.
• Perform the experiment using two breaths and record the measurement.
• Continue performing the experiment for more breaths.
• Ask students to estimate how far 10 breaths would take the balloon. Have them give reasons for their estimates.
• Perform the experiment and determine how close students’ estimates were.
• Repeat the experiment to verify data and repeat with other numbers of breaths.
• Create a pictograph for each number of breaths used, using a symbol (such as a drawing of a rocket) to represent the distance traveled for each.
• Ask students what they learned during this experiment. Answers will vary but might include: More air makes the balloon go farther. Consistency in airing up the balloon is important. Measuring accurately is important.
• Evaluate students’ ability to use non-standard measurement tools to accurately measure distances.
• Evaluate students’ ability to predict based on data.
• Ask students to draw a picture of the experiment in their journal or on a sheet of paper. Ask them to write a sentence about the results of the experiment or describe the results orally. Evaluate.
• Repeat the experiment using groups of five interlocking cubes as a nonstandard measuring tool. Students gain experience counting by 5s.
• Repeat the experiment and measure using a different size rocket. Compare the results.
• Encourage students to think of other forms of nonstandard measurement to determine the distance the balloon traveled. Use one or more of their suggestions and repeat the experiment.
• Set up two balloon experiments side by side in the classroom. Let the students “race” two balloons at one time. Vary the number of breaths in the balloons. Let students count the number of breaths and measure the distance the balloons travel.
• Have students apply what they learned in this experiment. Ask students to consider whether the amount of fuel in a rocket determines how far it travels. Ask students to consider other factors such as size and weight that may affect the distance a rocket travels.
• Encourage students to look at the depictions of rocket launches and think about what they now know about how a rocket works.

Science Fair Guide: Straw Rocket

In addition to the straw rocket materials , you’ll need a tape measure and craft foam.

Ask a Question

What amount of added mass causes the rocket to fly the farthest?

Gather Information

Air is made up of countless molecules: oxygen, carbon dioxide, etc. When these molecules bump into moving things, it slows those things down. This is a force called drag .

Flying things – like the straw rockets – need some mass to overcome drag. Mass is just how much matter (like molecules) is grouped together in an object. For example, a marble has more mass than a piece of popcorn. An object with more mass can more easily push past the air and resist drag.

If there's too little mass, then the drag will slow down the rocket before it’s travelled very far. However, too much mass, and the rubber band won’t be able to supply enough energy to get the rocket moving.

One last piece of information: a standard 4" mini glue stick weighs almost exactly 4 grams.

Make a Hypothesis

Using the information above, make an educated guess about how much mass will work the best. Your hypothesis should be a simple statement, such as: “5 grams of mass will cause the rocket to fly the farthest” (This is not necessarily the best hypothesis; it’s just an example).

Conduct an Experiment

Create one straw rocket, but don’t add any mass, like a piece of a hot glue stick, to the tip yet. Build the fins out of craft foam. You’ll be reusing this rocket quite a few times, and foam is much more durable than paper. You may want to make a second, identical backup rocket in case the first one gets too damaged.

Without any extra mass added, launch the rocket straight forward three times and record the distance travelled with a tape measure.

​Add a very small amount of mass (hot glue stick) to the tip. About a ½"-long piece is a good place to start. Launch three times again.

Remove that glue stick, and add a piece that’s ½" longer, then launch three times again.

Repeat until an entire 4"-long glue stick has been added to the rocket.

Setup the Controls

Controls are measures put in place to prevent unintended things from affecting your results.

Follow these procedures to ensure your data is accurate:

Stretch out the slingshot’s rubber band with your hands before beginning. The rubber band loosens quite a bit when it’s first used. Pre-stretching it will help ensure that each shot uses the same amount of energy as the one before it.

Make sure to fire straight ahead each test. Avoid aiming even slightly up or down.

Make sure to pull back the same amount for each test. Optional: Attach a ruler perpendicularly to the slingshot so you can pull back a precise amount each test.

After each test, inspect the rocket for damage. Make only the smallest repairs necessary. Avoid replacing fins or adding extra tape! These things can have a big effect on how far the rocket flies.

If you mess up a test (e.g. the rocket hits the slingshot when launched), then discard that result and test again. Record any discarded tests, and write a note about why you decided to retest.

Launch the rockets when it’s not windy.

Collect Data

Record the distance of each test. When finished, add up the results for each amount of mass added, then divide by 3 to get an average distance. For example, if a rocket with the mass of ½" of a glue stick flew 121", 102", and 93", then 121+102+93 divided by 3 is an average of 105.3".

Your data might look something like this (this is not real data; don’t use in your conclusion):

View the Rocket project

Make Observations

Describe any additional observations you made during the experiment. Be sure to include things might have affected your results such as launching errors, wind during some tests, or anything else unexpected.

Draw Conclusions

Look at your data and conclude which amount of weight caused the rocket to fly the farthest.

Present Findings

Present your main conclusion in a visual form, such as writing the average distance flown next to each piece of glue stick, and creating a graph that shows the distance the each one travelled.

Summarize your hypothesis, experiment method, the controls you put in place, and your raw data.

Write your conclusion, and explain why you think the results are the way they are.

Science Fair Central

Scientific Steps

Students who want to find out things as a scientist, will want to conduct a hands-on investigation. While scientists study a whole area of science, each investigation is focused on learning just one thing at a time. This is essential if the results are to be trusted by the entire science community.

Follow the Scientific Steps below to complete your scientific process for your chosen investigation, How do fins on a rocket affect its flight?

What is tested? Size of fins

What stays the same? Shape and number of fins, fin placement, type and size of rocket, propulsion system (amount of push), air movement, temperature, launch site

Data collected: Distance the rocket flies or trajectory (how straight the rocket flies)

What do scientists think they already know about the topic? What are the processes involved and how do they work? Background research can be gathered first hand from primary sources such as interviews with a teacher, scientist at a local university, or other person with specialized knowledge. Or use secondary sources such as books, magazines, journals, newspapers, online documents, or literature from non-profit organizations. Don’t forget to make a record of any resource used so that credit can be given in a bibliography.

After gathering background research, the next step is to formulate a hypothesis. More than a random guess, a hypothesis is a testable statement based on background knowledge, research, or scientific reason. A hypothesis states the anticipated cause and effect that may be observed during the investigation.

Consider the following hypothesis: If ice is placed in a Styrofoam container, it will take longer to melt than if placed in a plastic or glass container. I think this is true because my research shows that a lot of people purchase Styrofoam coolers to keep drinks cool.

The time it takes for ice to melt (dependent variable) depends on the type of container used (independent variable.). A hypothesis shows the relationship among variables in the investigation and often (but not always) uses the words if and then.

Design Experiment

Once a hypothesis has been formulated, it is time to design a procedure to test it. A well-designed investigation contains procedures that take into account all of the factors that could impact the results of the investigation. These factors are called variables.

There are three types of variables to consider when designing the investigation procedure.

• The independent variable is the one variable the investigator chooses to change.
• Controlled variables are variables that are kept the same each time.
• The dependent variable is the variable that changes as a result of /or in response to the independent variable.

Step A – Clarify Variable

Clarify the variables involved in the investigation by developing a table such as the one below.

Step B – List Materials Make a list of materials that will be used in the investigation.

Step C – List Steps List the steps needed to carry out the investigation.

Step D – Estimate Time Estimate the time it will take to complete the investigation. Will the data be gathered in one sitting or over the course of several weeks?

Step E – Check Work Check the work. Ask someone else to read the procedure to make sure the steps are clear. Are there any steps missing? Double check the materials list to be sure all to the necessary materials are included.

Data Collection

After designing the experiment and gathering the materials, it is time to set up and to carry out the investigation.

When setting up the investigation, consider...

Carrying out the investigation involves data collection. There are two types of data that may be collected—quantitative data and qualitative data.

Quantitative Data

• Uses numbers to describe the amount of something.
• Involves tools such as rulers, timers, graduated cylinders, etc.
• Uses standard metric units (For instance, meters and centimeters for length, grams for mass, and degrees Celsius for volume.
• May involve the use of a scale such as in the example below.

Qualitative Data

• Uses words to describe the data.
• Describes physical properties such as how something looks, feels, smells, tastes, or sounds.

As data is collected it can be organized into lists and tables. Organizing data will be helpful for identifying relationships later when making an analysis. Using technology, such as spreadsheets, to organize the data can make it easily accessible to add to and edit.

Analyze Data

After data has been collected, the next step is to analyze it. The goal of data analysis is to determine if there is a relationship between the independent and dependent variables. In student terms, this is called “looking for patterns in the data.” Did the change I made have an effect that can be measured?

Recording data on a table or chart makes it much easier to observe relationships and trends. There are many observations that can be made when looking at a data table. Comparing mean average or median numbers of objects, observing trends of increasing or decreasing numbers, comparing modes or numbers of items that occur most frequently are just a few examples of quantitative analysis.

Besides analyzing data on tables or charts, graphs can be used to make a picture of the data. Graphing the data can often help make those relationships and trends easier to see. Graphs are called “pictures of data.” The important thing is that appropriate graphs are selected for the type of data. For example, bar graphs, pictographs, or circle graphs should be used to represent categorical data (sometimes called “side by side” data). Line plots are used to show numerical data. Line graphs should be used to show how data changes over time. Graphs can be drawn by hand using graph paper or generated on the computer from spreadsheets for students who are technically able.

These questions can help with analyzing data:

• What can be learned from looking at the data?
• How does the data relate to the student’s original hypothesis?
• Did what you changed (independent variable) cause changes in the results (dependent variable)?

Draw Conclusions

After analyzing the data, the next step is to draw conclusions. Do not change the hypothesis if it does not match the findings.The accuracy of a hypothesis is NOT what constitutes a successful science fair investigation. Rather, Science Fair judges will want to see that the conclusions stated match the data that was collected.

Application of the Results: Students may want to include an application as part of their conclusion. For example, after investigating the effectiveness of different stain removers, a student might conclude that vinegar is just as effective at removing stains as are some commercial stain removers. As a result, the student might recommend that people use vinegar as a stain remover since it may be the more eco-friendly product.

In short, conclusions are written to answer the original testable question proposed at the beginning of the investigation. They also explain how the student used science process to develop an accurate answer.

Kids Workshops

To learn more visit, homedepot.com/kids

Kids Workshops provide a mix of skill-building, creativity, and safety for future DIYers every month in Home Depot stores across the country. After registering for the next Workshop, download these exclusive extension activities from Discovery Education. Each extension provides opportunities to reimagine or use their Workshop creation in an unexpected new way.

Lattice Planter

Explore the features of plants and consider how they impact our world. Students will select the type of plant they want to grow and map out a watering schedule to ensure it thrives in their Lattice Planter

Butterfly House

Do butterflies have a favorite spot to hang out? Students will create an observation chart, watch butterfly activity, and then analyze their results to select the ideal location for their Butterfly House.

Valentine Basket

Survey friends and family on what makes a card stand out from the rest and then brainstorm ways to make an original creation shine. Students will select a goal and use their creative talents to design a card to hold in their Valentine’s Basket. 

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Straw Rocket – STEM Challenge

January 29, 2024 By Emma Vanstone Leave a Comment

These straw rockets are very easy to make and great fun. You can make them plain or theme in different ways. We’ve made Pterodactyls and rockets!

They’re also a fantastic introduction to forces , gravity and trajectory!

Don’t forget I also have a book filled with rocket and space science experiments for kids. This IS Rocket Science is available from Amazon in the UK and bookstores in America.

Easy Straw Rocket STEM Challenge

There are two ways to make these: you can either use a wide straw as the rocket part ( sealed with tape at one end ) or use paper sealed at three ends so the open end fits over the straw.

You’ll need

Paper Version

Straw Version

Normal Straw

Paper clips

Felt tip pens

How to make a straw rocket

Paper version.

Cut a small strip of paper, fold in half and seal the top and long side opposite the fold with tape.

This should fit loosely over the top of the straw.

Place it over the straw and blow, it should shoot into the air!

Decorate if you want!

S traw Version

Cut the wider straw, so you have a segment about one-third the length of the normal-width straw.

Completely seal one end of the wide straw with sellotape so no air can pass through it. Check this by blowing down the straw. Does any air escape?

Draw a picture of a rocket or other space object on a piece of paper and use sellotape (double-sided works best ) to attach to the wider straw.

Place the wider straw onto one end of the normal straw and blow!

Watch your rocket fly!

Try pointing the straw at different angles and blowing harder/less hard to see how the flight of the rocket changes.

Straw Rocket Instructions and Template

If you’d rather make flying butterflies than rockets, the tamplate above works well.

Why does this happen?

When you blow air down the straw, it travels to the end and pushes its way out, taking the rocket straw segment with it as it moves. The harder you blow into the straw, the more energy the air has and the further the rocket will fly!

Change the trajectory

Find out what happens to the straw rocket if you point it straight up. How far does it fly? Does it fly differently if you point it horizontally?

What’s going on?

Two forces are acting on the straw rocket . Gravity is pulling it down while the force from the air blown down the straw is pushing it forward. These two forces combined give a curved movement. A real rocket needs to overcome the gravitational force downwards.

Straw Rocket Challenge – Extension Ideas

Add some weight to the straw rocket and see if that affects how far it travels. You could use cardboard instead of paper for the rocket or add paper clips!

Make lots of different themes for your straw rockets. Red Ted Art has some beautiful summer themed straw shooters that work in the same way.

More Rocket Science for Kids

If you’ve got kids who love space and rockets, you might like our easy bottle rocket experiment , film canister rocket or squeezy bottle rockets !

For younger children, I’d recommend a rocket mouse ! These are great fun for little ones, and bigger siblings might enjoy getting involved, too!

Contains affiliate links

Last Updated on January 29, 2024 by Emma Vanstone

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Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

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Science Projects > Physics & Engineering Projects > Rockets & Space Exploration  

Rockets & Space Exploration

Rocket science projects, balloon jet.

This is a very simple rocket that demonstrates the most basic principle of rocketry: how pressurized gas creates thrust.

What You Need:

• String or fishing line

What To Do:

1. Tie one end of the string to a chair or doorknob across the room from you.

2. Blow up a round balloon a couple of times to get it stretched out. Then blow it up and pinch the end closed so no air can escape. Holding the inflated balloon closed, have an assistant help you tape a straw to it.

3. Thread the straw onto the free end of the string. Hold the string taut and then let go of the balloon.

What Happened:

The air in the balloon is gas under pressure. The air pushes against the balloon, causing it to expand, but the balloon is also pushing back on the air. When gas or liquid is under pressure, it tries to escape. In the case of the balloon, it escapes out the open end. In a rocket, it escapes through an opening called a nozzle. As the gas escapes, it creates the thrust that propels your rocket forward (or a real rocket upward). This is because of one of Newton’s Laws of Motion: for every action, like gas escaping from a rocket in one direction, there is an equal and opposite reaction, like the rocket moving in the other direction.

To do some more experimenting with your simple balloon rocket, test how far it will go with different amounts of air: full, half full, a quarter full, etc. (You can measure the actual volume of air inside the balloon by using a flexible tape measure to measure the circumference of the balloon. Use the circumference to find the diameter: just divide the circumference by π (3.14). Next find the volume with the following equation: Volume = 1/6π (Diameter) 3 . After several tests, make a graph to show the relationship between the balloon’s volume and the distance it travels.) Another experiment idea is to see if you can design a way to control the flow of air through the ‘nozzle’ – if the air comes out too slowly there won’t be enough force to move the rocket forward, but if it escapes too quickly the rocket won’t go very far. Finally, try using different types of string for your balloon rocket to travel along. Do you think the balloon will travel the same distance along yarn as along fishing line? Why or why not? (Hint: friction!)

Rockets heading to outer space need a lot of energy to escape the pull of the earth’s gravity! Instead of a single rocket trying to do all the work, aerospace engineers build rockets that perform in stages. As the first rocket stage burns itself out, another one takes over. Try this NASA project to make a two-stage balloon rocket.

Film Canister Rocket

Unlike a balloon rocket, most rockets create the gas they need for thrust via a chemical reaction. A fuel (like liquid hydrogen) is mixed with a source of oxygen (often liquid oxygen) and burned in a chemical reaction that produces a lot of gas! In this project you can make a simple rocket and fuel it by a chemical reaction that produces carbon dioxide. Make sure you launch this messy rocket outside!

• Clear film canister (the kind where the cap fits inside the canister, rather than over the outside. See if a local photography shop has any extras they can give you. )
• Alka-Seltzer tablets
• Baking soda
• A piece of paper
• Cardstock or poster board

1. The film canister is the engine of your rocket. Make a body for it out of the piece of paper. Line up the open bottom of the canister slightly below the bottom (short) edge of the paper, then tape the longer edge to the canister and start rolling to make a tube. Tape the tube closed.

2. Cut out four triangular fins and one nose cone from the cardstock.

3. To make the nose cone, cut out a circle, then make a slit from the outer edge to the center. Overlap the paper at the slit and tape it to create a cone shape.

4. Tape the fins and nose cone to your rocket.

5. Turn the rocket upside-down and fill the canister 1/4 full with water. Add half of an Alka-Seltzer tablet, snap the lid on, turn the rocket over and back away. 3-2-1 blast off!

The Alka-Seltzer reacts with water to produce carbon dioxide. When enough carbon dioxide is produced to create pressure on the inside of the canister, it will force the lid to pop off so the gas can escape. As the gas escapes the rocket is propelled upward.

Try to measure how high your rocket goes compared to a nearby fence or a tree. Try it several times; do you get the same results each time? Does the rocket go higher if you add more or less water? Why do you think this is? What happens if you change the design of your fins or nose cone?

Now try it again with a different type of fuel. When vinegar and baking soda are mixed together, they produce carbon dioxide. Experiment to see how much baking soda and vinegar will launch the rocket the highest. (Some tips: You can either pack the baking soda in the lid with a damp thumb so that the reaction doesn’t start until you turn the rocket over, or you can wrap it in some tissue paper or toilet paper to delay the reaction starting and give you time to set the rocket right-side-up.)

More Rockets:

• Try using a balloon to build a rocket car
• Build your own water rocket , or experiment with our bottle rocket launcher .
• Power a rocket with combustion by building a whoosh rocket

Space Science Lesson

Exploring space.

2018 marks NASA’s 60th anniversary. NASA (National Aeronautics and Space Administration) was created in response to the Soviet Union’s successful launch of the first satellite, Sputnik 1. For many years the Americans and the Soviets tried to outdo one another in the ‘space race.’ The Soviets had the initial advantage – they launched the first satellite and put the first man in space. NASA, however, won the crowning glory: the moon. Here are a few highlights of the space age:

Apollo – Just eight years after the first American traveled in space, NASA successfully reached the moon. On July 20th, 1969, Neil Armstrong of Apollo 11 took the first human step outside Earth, saying ‘that’s one small step for man, one giant leap for mankind.’ The Apollo program had its share of setbacks, including a fire during a test on Apollo 1 that killed three astronauts, and an explosion on Apollo 13 that prevented a lunar landing and put the lives of the astronauts in grave danger. Nevertheless, six missions landed successfully on the moon, performed many scientific experiments, and brought back hundreds of pounds of moon rock. The last lunar landing was in 1972.

Space Shuttle – After Apollo, manned spaceflight has used the space shuttle, a partially reusable spacecraft that is launched by rocket and landed like a normal airplane. Five shuttles – Columbia, Challenger, Discover, Atlantis, and Endeavor – have been launched a total of 122 times. ( Challenger disintegrated after launch in 1986 and Columbia broke apart during re-entry in 2003. Fourteen astronauts were killed in the disasters.) The shuttle only flies into low-earth orbit, but even so it has truly expanded our understanding of the universe by carrying some of NASA’s most important satellites and probes into space. It sent Galileo on a ground-breaking mission to study Jupiter and its moons for eight years, plus it launched and serviced the Hubble Space Telescope. The space shuttle program will end in 2010 after 29 years of taking humans to space!

Hubble Space Telescope – If you’ve seen beautiful pictures of distant galaxies and star nebulae, it’s likely that they were taken by Hubble . Earth’s atmosphere makes it hard for land-based telescopes to get clear, sharp images. In space there is no atmosphere in the way. Hubble has taken deep field pictures showing us that even the darkest part of our sky is filled with thousands of galaxies.

Space Probes – Humans haven’t been any farther than the moon, so our discoveries about the solar system don’t come from eyewitnesses! Instead, a host of space probes have traveled through the solar system, taking pictures, testing the atmospheres of planets, and more. Some even land on the surface of another planet, like the Mars rovers Spirit and Opportunity. Some probes fly past multiple planets and keep going; others enter orbit and circle a particular planet for years. The Voyager probes passed several planets and are now nearly out of our solar system. Voyager 1 is 8.7 billion miles from the sun and is still traveling at nearly one million miles per day!

Science in Action: Interview with John Anderes

HST: When did you decide you wanted to work in aerospace engineering?

John: I actually entered college expecting to be a chemical engineer. However, after two years of inorganic and organic chemistry (seems like I blew up almost every experiment in the lab), I was ready for something else. I leaned towards subjects I enjoyed the most, applied math and physics.

HST: What was your favorite part of your job?

John: I’ve worked over the last 40 years in many different areas of the aerospace industry. By far, the most fun for me was in modeling and simulation: developing launch, on-orbit and even landing models of space vehicles and satellites.

(John’s simulations made sure a satellite could withstand all the stress put on it in different phases of its life cycle (e.g., launch, orbit, or even emergency landing for satellites that were carried on the Space Shuttle). He determined the maximum load the satellite could take, and then his calculations were used in the laboratory where the satellite was tested on shaker tables and in thermal, vacuum, and acoustic chambers.)

HST: How did technological advances change your job?

John: Of course, many technological advances were created by the aerospace industry itself. Just think of what your world today would be like if there were no satellites used for weather prediction, Direct TV, cell phones, and so forth.

Personally, changes in the computer take the prize. In the 60s, data was entered into the computer via punched cards or magnetic tapes. Even in the late 60s (Apollo landing era), I had to check computer calculations via slide rule and hand plot data on graph paper to more easily visualize results and trends. Now we can create three dimensional models that look like photographic pictures, and view results via color 3D movies. But in some ways, working in this new environment an engineer can lose perspective of the basics of the problem he’s solving and too easily believe what he’s seeing on the computer screen. One really needs to understand the limitations of the software being used.

HST: What do you think are the most interesting events in the aerospace industry?

John: I love astronomy, so the Hubble Space Telescope has to be top dog satellite in my book. Its reach into the heavens has been almost overwhelming even to ardent astronomers.

HST: What do you remember about the Apollo 11 moon landing?

John: It was a very exciting time. I worked for the company that built the guidance systems for Apollo. I remember very distinctly watching the event on TV with my wife. I took a black and white fuzzy picture with our camera of the TV screen.

HST: Do you have any advice for someone who wants to become an aerospace engineer?

John: Enjoying science, math, physics and engineering goes a long way. Engineering requires logical and creative thinking; that’s what makes it so much fun. It is really great to be part of our expansion into the heavens. Practically, when in college, taking a semester to co-op at NASA or in an aerospace firm is very beneficial.

Science Links

Check out amazing views of the universe at the Hubble Space Telescope website .

Get a tour of the International Space Station with this interactive guide.

Try your hand at some space science with these cool Sci Games .

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Balloon Rocket

The balloon rocket is a great science experiment for kids to grasp the concept of force and energy. By involving in this activity, they also garner a lot of fun as it enables them to build their own balloon-powered rockets, something that is no less than an exciting toy.

Balloon Rocket Experiment

On releasing the air contained in a fully blown balloon, it moves forward along a straight string to which it is attached.

• 1 balloon (long ones work best)
• About 10-15 ft long kite string
• 1 plastic straw
• Tie one end of the string to a door knob, chair or any other support.
• Pass the other end through the straw.
• Stretch the string tightly by pulling the free end and tie it to any other support.
• Move the straw to one end of the string. Blow the balloon up fully.
• Pinching its opening without tying it, tape it horizontally to the straw ensuring that the opening faces the support that is closest to the balloon.
• Let go of the pinched end and watch the balloon propel itself forward from one end of the string to another. Can you hear a noise? It is of the blown air escaping out.

How to Make a Balloon Rocket: Video

Explanation of the balloon rocket lab.

On releasing the nozzle, the air that is stored inside the balloon at a high pressure rushes out in the backward direction with a lot of force because of relatively lower pressure outside. This is the action. Now According to Newton’s 3 rd law of motion, every action has an equal and opposite reaction. As a result, the thrust caused by the backward movement of the air causes the balloon to go in the forward direction. According to Newton’s 2 nd law, the thrust produced is directly proportional to the acceleration produced in the rocket and they occur in the same direction.

The same principle is utilized in rockets. A part of it is filled with fuel. On burning, it gives rise to smoke and gasses that rush out of its rear in the downward direction, causing a thrust on the rocket to gain upward momentum.

According to Newton’s 1 st law of motion, a body continues to be in a state of rest or of motion unless acted upon by some externally impressed force to act otherwise. Note that the only resistance to the motion of the balloon rocket is air resistance and the friction on the string that causes it to stop eventually. In the absence of both these factors, its velocity would never be zero. This helps us to conclude that a balloon rocket can operate in space that is a vacuum. This fact applies to real rockets too that are sent to a planet’s orbit in outer space.

Further Investigation

• Measure the circumference of the widest part of a small inflated balloon with a tape. After performing the experiment, measure the distance traveled by setting a ruler along the straight string. Repeat with bigger balloons having greater circumferences at their centers. Tabulate the results and plot it on a graph taking the circumference (or radius) along the X-axis. How does it change?
• Take different shapes of balloons and check how far they go. How does the rocket design affect the distance traveled?
• Tape the balloon to the string in such a way that its nozzle is not parallel to the string but aligned at a certain angle. Execute the experiment. Does the rocket move as expected?
• Use other types of material for your line like twine, fishing line or ribbon. How does it affect the distance up to which the balloon rocket travels?

Do let us know of your observations and let us figure out the reasons for it.

Applications of Balloon Rockets

You can make a racer balloon rocket car by applying the above principle of balloon rockets.

Turn it into a fun game by allowing children to race against each other with their homemade balloon rockets. Help them with tips and tricks to make it faster. Even preschoolers can enjoy its working as a toy without having to delve much into the details. It is also an ideal project for demonstration at science fairs.

Published on August 9th 2016 by Papiya Dutta under Science Fair Projects . Article was last reviewed on 15th November 2023.

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Make A Balloon Rocket

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 !

HOW TO MAKE A BALLOON ROCKET

BALLOON ROCKETS

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…

• Santa’s Balloon Rocket
• Valentine’s Day Balloon Rocket
• St. Patrick’s Day Balloon Rocket

HOW DOES A BALLOON ROCKET WORK?

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!

NEWTON’S THIRD LAW

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!

CLICK HERE TO GET YOUR FREE BALLOON ROCKET PROJECT!

BALLOON ROCKET EXPERIMENT

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

INSTRUCTIONS:

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!

EXTEND THE LEARNING:

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?

BALLOON ROCKET SCIENCE FAIR PROJECT

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.

• Easy Science Fair Projects
• Science Project Tips From A Teacher
• Science Fair Board Ideas

MORE FUN THINGS TO BUILD

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.

~ Projects to Try Now! ~

Cool Science Experiments Headquarters

Making Science Fun, Easy to Teach and Exciting to Learn!

Science Experiments

Balloon Rocket Science Experiment – A Balloon that Flies like a Rocket

3-2-1 Blast Off! This simple and fun science experiment teaches children about Action and Reaction. Using everyday household items, children learn how the force of air moving in one direction can propel balloon in the opposite direction, much like a rocket!

Below you’ll find a supplies list of everything you need, printable instructions, and the scientific explanation of how it demonstrates Newton’s Third Law of Motion in a fun, hands-on way. It’s so much fun, your kids will want to do it over and over with balloons of different shapes and sizes. 

JUMP TO: Instructions | Video Tutorial | How it Works | Lab Kit

Supplies Needed

• Drink Straw
• Two objects of the same height that you can tie a string to. We used two chairs

Balloon Rocket Science Lab Kit – Only $5

Use our easy Balloon Rocket Science Lab Kit to grab your students’ attention without the stress of planning!

It’s everything you need to  make science easy for teachers and fun for students  — using inexpensive materials you probably already have in your storage closet!

Balloon Rocket Science Experiment Instructions

Wondering how to create a balloon rocket? It’s easy! Simply follow these step by step instructions.

Step 1 – Position two objects of the same height (We used chairs) about 10 feet apart. Then grab your string and securely tie one end to one of the objects. 

Step 2 – Next, get your plastic drinking straw. If you are using a “bendy” straws with the flexible piece on one end, cut off the flexible part so you are left with a straight straw.

Thread the string through the straw and place two pieces of tape near the middle of the straw. P osition the two pieces of tape near the middle of the straw is important because if you place them near the ends of the straw, the straw will bend when the balloon deflates and the rocket won’t move as quickly.

Step 3 – Then tie the loose end of the string to your second object (We used a second chair across the room) and make sure the string is tight. If the string isn’t tight, move the objects farther apart until it is.

Step 4 – Blow up the balloon and hold the end so the air can’t escape and use the two pieces of tape to secure the balloon to the straw.  

Take a moment to make observations. What do you think will happen when the you let go of the end of the balloon? Write down your hypothesis (prediction) and then continue the experiment to test it out and to find out if you were correct.

Then move the straw and balloon to one end of the string. And once you are ready….

Step 5 – Let go of the balloon and watch what happens! Do you know what caused the balloon to rocket across the room? Find out the answer in the how does this experiment work section below. Then inflate the balloon again and repeat again and again.

Balloon Rocket Science Experiment Video Tutorial

How Does the Science Experiment Work?

The balloon flies across the string because of air and thrust. Thrust can be explained by Newton’s Third Law of Motion . Newton’s third law states that for every action there is an equal but opposite reaction. As the air is released out of the balloon in one direction, the force propels the balloon in the other direction. This equal but opposite force causes the balloon to fly across the string like a rocket!

I hope you enjoyed the experiment. Here are some printable instructions:

Balloon Rocket Science Experiment

• Two objects of the same height that you can tie a string to. I used chairs.

Instructions

• Position two objects of the same height (I’m using chairs) about 10 feet apart and grab a piece of string.
• Tie one end of the string to one of the objects. Make sure it is securely fashioned.
• Next, get a straight plastic drinking straw. If the straw is one of the “bendy” straws with the flexible piece, cut off the flexible part so you are left with a straight straw.
• Place two pieces of tape on the straw. Note: Be sure to position the two pieces of tape near the middle of the straw. If you put them near the ends of the straw it will bend when you blow up the balloon and the rocket won’t move as quickly.
• Thread the string through the straw
• Tie the loose end of string to the back of your second object (I’m using another chair) and make sure the string is tight. If the string isn’t tight, move the objects farther apart until it is.
• Blow up the balloon and hold the end so the air can’t escape and use the two pieces of tape to secure the balloon to the straw.
• Move the straw and balloon to one end of the string. And once you are ready…..
• Let go of the balloon and watch as it rockets across the string! Then inflate the balloon again and repeat again and again.

Reader Interactions

March 30, 2016 at 11:05 pm

you balloon rocket is so cool!

– Misk Algaysi

May 10, 2017 at 6:20 pm

The balloon wind is pushing against the regular wind which makes it fly and the rope is inside the straw which also makes it go faster.

October 28, 2018 at 10:27 pm

Cool experiment. The balloon flew like a rocket!

June 8, 2023 at 7:55 am

This is a really cool experiment! I am going to try this for my science experiment.

— Matthew Jensen