I love labs that challenge students to think. If its loud and makes a mess, all the better! This challenge accomplishes all of these goals.
The Alka-Seltzer Rocket Challenge:
The Challenge: Using the basic construction suggestions below, and using any of the available materials, design a rocket that will propel the greatest monetary value to an elevation of at least 1 meter above its start location.
Here are the materials you set out for students:
- Alka-seltzer tablets
- small clear plastic cup (I prefer clear so you can see what's happening)
- film canister
- water and/or club soda
- meter stick
- various coins
- mortar and pestle
- graduated cylinder
- safety goggles
Here's the basic design: The coins are taped to the cup. Any given amount of liquid inside a film canister, alka-seltzer dropped in, film canister lid to cover and a plastic cup upside on top. The CO2 will pop off the canister lid, and push the cup into the air. Its AWESOME.
Given the basic design, set students free to explore. Concepts include force, lift, gravity, propulsion, and fun. They'll need a few "free-bees" as the surprise factor is so enjoyable, student have a hard time focusing at first. Allow them to tweak their procedure and change materials to meet the challenge.
Depending on your goals, you can focus students on the aspect of the scientific research project you want them to experience. For example, maybe this activity will help your students see how important it is to record observations in a laboratory notebook. Or maybe you want them to focus on problem-solving and critical thinking determining how to change their design to make it work better.
As you can see in the photo below, some students wanted to see how high they could get the cup to go without any coins on it. Impressive huh?
Most students determine that it is best to work together, one drops the tablet, one puts on the lid, and then the first puts on the cup.
It doesn't seem to matter that you know the cup is about to fly into the air, its EXCITING every time!
Here are the post lab questions included with the student lab. I emphasize the process, by asking about what went well, what they learned from their successes and failures! You could have students write these out in their lab notebook, or just explain verbally to one another and the class. It leads to a rich discussion regarding the scientific method.
1. What design issues did you run into trying to get your rocket to propel higher?
2. What modifications made the biggest impact on improving your rocket design?
3. Can you explain why that modification worked better than others?
4. Describe a modification you made that didn’t have a big impact. What did you think it would do? What happened instead?
5. Draw AND label your rocket design and measurements that performed the best.
6. If you had more time and more materials, what would you do to improve your rocket?
Feel free to download the student Alka-Seltzer Rocket Challenge Lab Sheet. It lists the materials, shows the basic design, and has a list of post lab questions students can answer regarding the design process. Enjoy!