Developing an Early Love of Science One Experiment at a Time

In my opinion, if you want a kid to become interested in science, all you need to do is launch something several feet into the air. Making a film canister rocket fits the bill perfectly as a simple experiment for kids that they will absolutely love.

Learn how to make a film canister rocket that launches several feet into the air! Get to know the science behind the film canister rocket experiment by learning about the secret ingredient; Alka-Seltzer. Experimenting with film canister rockets is a fun and engaging way for kids to learn simple chemistry.

It is best to launch film canister rockets outside. Be sure to stand back a few feet and wear safety glasses. You never know how high the canister rocket is going to fly!

Update: After we made our first Alka-Seltzer film canister rocket we got a little bit hooked. Since the first edition of this post was written we have used film canister rockets to make interesting firework paintings and we have used dry ice instead of Alka-Seltzer to launch the canister rockets. There are so many ways to experiment and have fun with exploding film canisters!

How to Make a Film Canister Rocket

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Assembling a film canister rocket is very simple. I gathered the following supplies:

  • A plastic bottle with a snap top. The little canisters that hold 35 mm film work the best, but I couldn’t dig any of those up this time. I used a different snap top bottle and it worked fine. (I used these Airborne canisters that I found in the pharmacy, but I have also used M&M’s Minis canisters. There are definitely ways to make Alka-Seltzer rockets without film canisters!)
  • Water
  • Alka-Seltzer tablets
  • Optional: Thin cardboard to make fins and a nose cone for the canister rocket. We cut up an old cereal box.
Learn how to make a film canister rocket that launches several feet into the air! Get to know the science behind the film canister rocket experiment by learning about the secret ingredient; Alka-Seltzer. Experimenting with film canister rockets is a fun and engaging way for kids to learn simple chemistry.

I cut out fins and a nose cone for our canister rockets. I attached the them with tape to the canister, but I’m thinking that got glue probably would have worked better. If you choose to make fins and a nose cone, make sure to attach the nose cone on the bottom of the bottle so that the cap-end is facing down at launch time.

Alka-Seltzer Rockets

We headed outside with the canisters, some water, and a handful of Alka-Seltzer tablets.

Some experimentation may be necessary to figure out the best ratio of water to tablets to add, but experimentation and learning is what we’re all about, right?

We had the most success with filling up the film canister with water, leaving about 1/2 inch of head space at the top. We dropped in one Alka-Seltzer tablet, quickly snapped the bottle close, and stood back!

After some serious fizzing, bulging, and leaking, the film canister rocket launched off the ground!

If you find that one tablet wasn’t enough to make it launch, try it again with two tablets. Or fill the bottle up with more water. Some experimentation may be necessary, but that’s all part of the fun!

You can always experiment to compare how it works with cold water versus hot water, how it works right side up versus turning the bottle upside down, etc. Record your findings and leave a comment letting me know what you found!

Learn how to make a film canister rocket that launches several feet into the air! Get to know the science behind the film canister rocket experiment by learning about the secret ingredient; Alka-Seltzer. Experimenting with film canister rockets is a fun and engaging way for kids to learn simple chemistry.

Film Canister Rocket Experiment

So what makes the explosion happen? It is actually the same chemistry that happens when you mix baking soda and vinegar together. An acid plus a base mix to form carbon dioxide gas, which are the bubbles you see. When enough carbon dioxide has been produced the pressure builds until the container can no longer contain it, at which point the top pops off and the gas and liquid explode out.

Alka-Seltzer is made of citric acid and sodium bicarbonate (baking soda), which acts as a base. When the tablets are solid and dry the acid and base don’t react, but as soon as they are immersed in water they react to form carbon dioxide. This is what causes the explosion. You can even alter this activity just a tiny little bit to make your own lava lamp! (No explosion there, just cool colored bubbles.)

Alka-Seltzer Film Canister Rocket

We have film canister rockets several times now. The first time we did it as part of a unit study on volcanoes. I wanted to show the kids that when the pressure builds up under the earth’s crust it can literally blow the top off of a mountain in a volcanic eruption. (This is how Mount St. Helens exploded in 1980.) This video below illustrates that explosion very well.

The second time we did this activity we actually made our bottle into a rocket and set it off with the cap-side down. The kids LOVED this. We have set off our rocket no less than 20 times now! You can see in this video that sometimes we go a very small lift off, sometimes it was a bit bigger, and one time it flew over my head!

Experiment to see what happens when you add more/less water, vary the temperature of the water, add more/fewer tablets, etc. The results may surprise you!

More Outdoor Science for Kids –>

Create an impressive soda geyser eruption using dry ice and Diet Coke! A jaw-dropping dry ice experiment for adults and kids alike!
14 amazing hands-on sun science experiments for kids. Fantastic during the summer, for a space unit, or for special events like the total solar eclipse!
Make your own ice slush drink this summer using simple science! All you need is fruit juice, salt, and ice. Ice slush is the perfect summer treat!
Simple Experiments for Kids, STEM activities for kids, Science experiments for kids

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STEM Saturday

By |2018-04-11T18:29:48+00:00March 21st, 2015|Five Minute Science, Science, STEM Saturday, Summer|6 Comments

6 Comments

  1. Christy McGuire September 26, 2014 at 3:41 am - Reply

    My son has had a perennial interest in doing a rocket based on vinegar and baking soda. We have been struggling to find a good solution for the top. This sounds like what we may be looking for!

  2. Crystal September 26, 2014 at 5:26 am - Reply

    Yes, that’s awesome! I’ve seen it done with baking soda and vinegar. Just make sure you invert the bottle after you close it so you get some good lift-off! Let me know how out goes: )

  3. Angela April 1, 2015 at 5:58 am - Reply

    Oh my gosh, I am going to get the supplies for the rocket today. We live on the Space Coast of Florida and are very interested in anything space so I know my kids will love this, thanks! 🙂

  4. Eileen Teo April 1, 2015 at 6:43 am - Reply

    I love how you made it! Look so simple! Thank you for joining with us #Pintorials

  5. Jolanthe April 9, 2015 at 9:23 am - Reply

    My kids would love this! Adding it to our summertime projects!!

  6. D February 14, 2018 at 5:23 pm - Reply

    I couldn’t find Alka_seltzer at the Dollar Tree so I used Efferdent tabs, they were just as effective.

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