How to Make a Rocket with Alka Seltzer
Making a rocket with Alka Seltzer is, as you can imagine, a favorite activity for students!
Plus, it’s a simple and inexpensive activity. We recently gathered with a few friends and the kids had a great time using recycled water bottles to make a rocket with Alka Seltzer.
And, best of all mini rockets launched with Alka Seltzer have built-in physics and chemistry lessons. Let’s don’t just read about Newton’s Third Law of Motion, let’s launch it into action!
We will also show you how we took this activity further and turned it into an experiment.
In the first part of this post, we will cover the straightforward instructions for making a rocket with Alka Seltzer. I’ll go into how you can turn this into more of a chemistry experiment to help your children learn about endothermic chemical reactions.
How to Make a Rocket with Alka Seltzer – A Brief History of Antacids
Science paired with history can make for some fascinating conversations!
The early antacids were not called antacids; however, there were remedies based on natural ingredients.
In our research on this, the earliest record of an antacid was in 350 BC. The Sumerians used natron, a mineral salt found in dried lake beds. It consisted of hydrated sodium carbonate. This substance was used as a cleaning substance to make glass and preserve mummies. Wow! It’s amazing what you learn doing a little research.
In 1887 Johnson and Johnson came out with a stomach-settling product containing papaya extract. Their product was called Papoid and sold until the 1950s.
In 1931 Alka Seltzer was introduced. Since then, it’s been settling upset stomachs, relieving headaches, and launching thousands of little pop rockets!
Make a Pop Rocket with Alka Seltzer
Make a pop rocket with alka seltzer, water, and a few other items. Test different variables such as liquid temperature, launch angle, launch height, and more.
Materials
- Alka Seltzer (Have plenty on hand, this is a very fun experiment!)
- Water, vinegar, and any other liquids you want to test
- Empty water bottle
- Launch "Pad". We used an empty plastic container. See the photos.
- Protective eye wear
- Cork that fits in the water bottle but isn't too too tight and isn't so loose the liquid runs out.
- Table
- Safe, open area for launching the rocket
- Optional: Stickers for decorating the rockets
- Measuring tape, pencil, and worksheets for measuring distance. You may opt to have your students make less precise notes and observations.
Instructions
- Determine what liquids you are going to test. Will they be hot vs cold?
- Identify your launch area and clear the surrounding area of objects, people, pets. Always point the rocket away from people, buildings, and animals.
- Decorate the rockets with stickers.
- Assemble the Alka-Seltzer, liquids, paper towels, launch "pad", safety goggles.
- Head out to the launch area. Everyone but the person launching the rocket should stand a safe distance away.
- The reactions happen quickly, so the person launching needs to pour in the liquid, add the Alka Seltzer, put the cork in the bottle quickly enough and not too loose or too tight, shake it, and drop it in the launch pad, aimed away from people, pets, and buildings.
- Take measurements if you are being precise. We knew we couldn't get too precise, so we put our markers where the rockets landed and then measured after we were finished.
Notes
We had over 40 Alka Seltzer tablets and used them all. We tested Sprite, vinegar, hot water, hold water, and hot coffee.
Testing Variables When Making a Rocket with Alka Seltzer
If you’d like to extend this activity into an experiment rather than just a cool activity, there are some variables that can be tested. The rockets and the endothermic experiment listed after the rocket instructions, are good opportunities to teach about dependent, independent, and control variables.
If you download the accompanying printable for these activities and experiments, you’ll get a printout you can use that covers these variables and has recording sheets for data collected.
When we did our rockets, we did change the water temperature and the liquid we used. These are our independent variables. We were testing whether the temperature of water affects the distance traveled. We were also testing the type of liquid – hot water vs hot coffee (We kept the temperature the same). You can also test 3 crushed tablets vs 2 crushed tablets or shaking 5 times vs. not shaking.
Our launches included testing various liquids and various temperatures of liquids:
- Hot water (heated in the microwave for a few minutes)
- Cold water from the refrigerator
- Room temperature water
- Just-brewed coffee
- Room temperature vinegar
You can look at:
- Cutting up the tablets vs. leaving them as solid tablets
- Changing the temperature of the water hot vs cold, room temp vs cold hot vs room temp
- Changing the type of liquid used, other than water – vinegar, vegetable juice, orange juice, Sprite, coffee
- Shaking the tablets and water before launch or not shaking
Variables we did control (or tried to) when measuring distance traveled as consistently as possible:
- Launching form the same table height
- Launching with the same surrounding wind speed
- Placing our launch “pad” on the same spot on the launch table
- Using the same amount of Alka Seltzer. This was difficult to do, and we discussed ways we could improve this process by really crushing the tablets with a rolling pin and using a funnel.
- Using the same shake-cork-place in box process.
We did crush our tables from the start. Although, getting all of the pieces in the bottle was a challenge. We tried a funnel, but pieces got stuck. We did brainstorm ideas for better control and consistency. One suggestion was to crush the Alka Seltzer with a rolling pin and using a funnel to pour it in the bottle.
There are two recording sheets, one each for the rocket activity and the endothermic reaction activity. Again, choose how much of this activity you want to do. Make it as formal or informal as you like.
You may not want to use any recording sheet and informally measure how far each rocket went. Did the hot vs. cold water go farther? Did shaking more or less affect height and distance?
There is no right or wrong way to organize this activity. However, it is important to teach about dependent variables, independent variables, and control variables. So, you might want to take this further by completing the endothermic reaction experiment below.
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A Few Notes of Prep for Your Alka Seltzer Rockets
You will need:
- Empty water or 16-ounce soda pop bottles
- Stickers for decorating the rockets. We decided not to go with adding straws or other decorations that could fly off into an eye.
- Cork or bottle stopper, but make sure it forms a good seal; but will come off when you pull on it. You shouldn’t have to really work to get it un-stopped.
- Alka Seltzer tablets – We bought ours at the dollar store. Important: Figure out what you think you’ll need, then multiply it by 10! So, consider what you think you might need and plan for three tablets per launch—plan for test runs and extra ideas your children will want to test.
The process:
- Remember, science and STEM is about testing ideas, and what you think might or might not happen. Allow time and material for your children to take ownership of this activity and want to test a few changes in variables.
- Your launch area must be outside.
- Everyone must wear eye protection.
- Do not point the bottles at anyone or any animal; point away from structures or cars. A big wide open area with no one and no buildings around is best.
- Students will need to move quickly.
- Try to get as much of the Alka Seltzer in the bottle. Put the top on quickly, pointing AWAY from everyone.
- Use a launch “pad” – we used a deep plastic container.
- Have fun!!
Make a Pop Rocket with Alka Seltzer
Make a pop rocket with alka seltzer, water, and a few other items. Test different variables such as liquid temperature, launch angle, launch height, and more.
Materials
- Alka Seltzer (Have plenty on hand, this is a very fun experiment!)
- Water, vinegar, and any other liquids you want to test
- Empty water bottle
- Launch "Pad". We used an empty plastic container. See the photos.
- Protective eye wear
- Cork that fits in the water bottle but isn't too too tight and isn't so loose the liquid runs out.
- Table
- Safe, open area for launching the rocket
- Optional: Stickers for decorating the rockets
- Measuring tape, pencil, and worksheets for measuring distance. You may opt to have your students make less precise notes and observations.
Instructions
- Determine what liquids you are going to test. Will they be hot vs cold?
- Identify your launch area and clear the surrounding area of objects, people, pets. Always point the rocket away from people, buildings, and animals.
- Decorate the rockets with stickers.
- Assemble the Alka-Seltzer, liquids, paper towels, launch "pad", safety goggles.
- Head out to the launch area. Everyone but the person launching the rocket should stand a safe distance away.
- The reactions happen quickly, so the person launching needs to pour in the liquid, add the Alka Seltzer, put the cork in the bottle quickly enough and not too loose or too tight, shake it, and drop it in the launch pad, aimed away from people, pets, and buildings.
- Take measurements if you are being precise. We knew we couldn't get too precise, so we put our markers where the rockets landed and then measured after we were finished.
Notes
We had over 40 Alka Seltzer tablets and used them all. We tested Sprite, vinegar, hot water, hold water, and hot coffee.
How to Make a Rocket with Alka Seltzer – A Brief Explanation of the Chemistry and Physics
The Physics Behind Rockets Made With Alka Seltzer
There is a lot of physics involved with this activity and experiment. Rockets launched with Alka Seltzer are an excellent example of the action-reaction principles of Newton’s Third Law of Motion: For every action there is an equal and opposite reaction.
When the chemical reaction happens between the water and Alka Seltzer, carbon dioxide is produced and causes pressure within the stopped-up bottle. When the bottle cannot hold anymore, the cork pops off and the bottle shoots into the air.
The bottle rocket travels upward with a force that is equal and opposite to the downward force that propelled the water, carbon dioxide, and cork.
Let’s Look at the Chemistry of Rockets Made With Alka Seltzer
Alka Seltzer contains three active ingredients: acetylsalicylic acid (aspirin), sodium bicarbonate (baking soda), and anhydrous citric acid.
The citric acid interacts with the sodium bicarbonate and water to form the bubbles or effervescence.
Let’s review a few basics. A chemical reaction occurs when molecules either form bonds or break bonds.
Before the reaction, the chemicals we begin with are referred to as the reactants. Then, once the reaction occurs, the chemicals that are produced as a result of the reaction are called products.
The starting chemicals before a reaction are called the reactants, and the chemicals produced are called the products. The reaction in this activity involves using sodium bicarbonate and citric acid to produce water and carbon dioxide.
The Alka Seltzer consists of sodium bicarbonate, which is a base, and citric acid, which is an acid. They do not react with one another when they are as dry tablets.
However, when we put them in water, the sodium bicarbonate and the acetic acid are released and can react.
They have to be able to react with the right amount of energy and at a right angle. This happens in the water, but if you change a few variables, this reaction occurs more quickly.
We’ll be testing some variables in this activity and experiment.
So, carbon dioxide is released when the sodium bicarbonate (the base) mixes with the acidic acid (the acid), which is indicated by the bubbles produced. The water helps release them from their solid form (the Alka Seltzer tablet).
What happens if we use something other than water or a liquid that is water and something else, like soda pop, vinegar, or coffee (which we tested)?
Endothermic Experiment with Alka Seltzer
Before enjoying the rocket part of this activity, you can do a quick endothermic reaction demonstration.
Or you may opt to do this after. Everyone is always excited to get right to the rockets!
If you want to read more about endothermic reactions in detail, check our post here.
In an endothermic reaction, heat is absorbed at the same time the chemical reaction is taking place. This means that the liquid in the beakers should be cooler after the Alka Seltzer is dissolved in the water or vinegar used in this portion of the experiment. Let’s test this out.
Note: I didn’t give an explanation of endothermic, as it is covered here.
What you need to gather:
- Vinegar
- Hot water (we put tap water in the microwave for 65 seconds
- Cold water that has been in the refrigerator a few hours
- Room temperature water
- Room temperature vinegar
- Any other liquids that students may want to test
- 1 Alka Seltzer tablet per beaker or glass container you are using
- Thermometers that will withstand up to 180 degrees F (We had a broken lab thermometer during our first run of this activity, so we used a candy thermometer 🙂 )
- Measure 100 ml of hot water into a beaker and 100 ml of cold water into a second beaker. This is a great time to teach your children to properly read the meniscus when measuring liquids.
- Place a thermometer in each and let sit for a minute. Record the temperature on the lab sheet.
- Have one person drop a tablet into both beakers at the same time, while someone starts a stopwatch (use a phone). If you have enough helpers, start two stop watches and stop one of them when the first tablet to dissolve is done dissolving.
- Call out when the first tablet is dissolved, stop that stop watch if you are using two stopwatches, and have someone record the time.
- Stop the stopwatch when the second table is dissolved.
- If you are recording, write the time for the second stopwatch on the lab sheet.
- Next, put the thermometers in the liquids, watch the temperature move, and at about a minute, record the temperatures. What happened to the temperatures?
- Wash out the beakers thoroughly and run the next test, repeating the steps above.
- Record all results and answer the discussion questions on the sheet.
I urge you to try room temperature water and vinegar.
Look at the results of each trial on the lab sheet. What do you notice about each?
How does temperature affect the dissolution rate of the Alka Seltzer?
Doe more acidic liquids react faster, slower than water?
If you do want to delve more into the endothermic reaction, check out this post.
Don’t forget to download our recording sheets, where we briefly cover dependent, independent, and control variables with some practice scenarios too.
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