Rubber Stopper Launcher: How to Launch Over 100m Using a Gas Reaction

[Karshtakavaar]

Hello! I'm neck-deep in concept designs, and honestly, I am swamped. I'm participating in an experiment to launch a rubber stopper from a bottle using a gas-producing reaction. My most recent design structure used dry ice, and a chamber made of metal, with the dry ice proportioned out inside both the chamber and the bottle to match the pressure on the inside of the bottle as the dry ice expanded. This allowed me to restrain the stopper, and build up pressure inside the bottle without bursting the bottle. This, however, apparently classified as "a bomb", and was consequently banned from use in the experiment.

My question is what I should do now. I would like to launch this rubber stopper over 100-150m. The stopper (made of rubber) weighs about 85g, and the base is ~1.45cm wide, with the rest coning out to a diameter of ~2.65cm, and the only thing allowed to launch the stopper is a gas reaction, either physical or chemical. I'm launching it from a plastic 125mL bottle, with a cap ~1.85cm wide. A regular baking-soda-vinegar reaction doesn't launch it more than ~50-60m. Any ideas on how to achieve this?

 

[Danger]

I'd like to know what age range you're in before commenting. There are certainly several ways to do it, but many of them might be quite dangerous to both you and your surroundings if something goes wrong.
In a school situation, anything that I suggest should be bounced off of a teacher (verbally, not physically) before construction.

 

[Karshtakavaar]

16 Years Old

 

[Danger]

I just realized that my initial idea wouldn't be what you need. That was to use a calcium-carbide/water reaction which produces acetylene. You'd still have to ignite it, though, which I don't believe fits your rules.
How about sodium/water? I think that the result is self-igniting, but I'm not sure.

 

[Karshtakavaar]

No combustion reactions, sadly. I think I'm going to use dry ice, like I said in the original post, just without the structure that let me increase pressure around the bottle. I was mainly looking for ways to increase possible distance by altering the bottle, or the environment around the bottle. It would be awesome if I could find a gas that expands faster than dry ice, though.

 

[Danger]

Okay; I misunderstood your intent. Sorry.