Improve My Bottle Rocket

[RookieScouter]

Our pack is participating in a community event with our council. We chose to do bottle rockets. This was a fun event for our scouts so I would like to share with others. How I made our bottle rockets: 2-liter soda bottle, 3 Tbsp Baking Soda, 2 Cups Vinegar, Duct Tape, 3 Pencils, Construction paper to decorate, One cork, and Paper Towels

1. Assemble and decorate your rocket, using the pencils as feet.

2. Secure them to the bottle using duct tape.

3. Add vinegar to the bottle.

4. Add 3 Tbsp baking soda onto a small square of paper towel.

5. Roll the paper towel tightly enough to fit inside bottle, and so that no baking soda can spill out.

6. With an adult scouts place paper towel full of baking soda inside the bottle and plug with a cork. (We ask that they do not plug too tightly, but don’t allow any liquid to spill out.)

7. Scouts take the bottle to an adult leader. Turn the bottle upside down, place it on it's feet and STAND BACK!

What would you change or recommend material wise to make this easier? Although our scouts loved this activity we ended up with vinegar on us or some bottles took a lot longer to go off. Just looking to improve our bottle rockets and hear what worked for others. 

*I would be interested in changing pencils to something else. 

[seattlecyclone]

This year our pack did something more like https://www.instructables.com/Pump-Rocket/. No vinegar/baking soda. Instead the pressure comes from air delivered through a bike pump, and a bit of water in the bottle becomes propellant once the pressure ejects the cork.