Hacker News

points by nine_k 3 days ago | 0 comments

Will birthday balloons be filled with hydrogen instead? They would have a much stronger pull!

I would've loved that as a kid. For that matter, I did actually fill some balloons with hydrogen using vinegar and something (might've cut some magnesium off one of those primitive fire starters, or I might've used a weaker metal, can't quite remember). I think I used the glass tube Costco used to use as a vanilla bean container to strap the balloon onto.

[–] garlic_enjoyer 3 days ago

Zinc and vinegar is what you're looking for. Our high school science class had us fill plastic pipette bulbs to make rockets.

[–] hansvm 3 days ago

Zinc would've worked too, I might have clipped the corner off some pennies or something. Magnesium works too though, and I definitely had access to magnesium. It was awhile ago though, so I'm not sure what I did.

[–] garlic_enjoyer 1 day ago

I didn't know magnesium worked too. Glad to have learned something!

[–] nine_k 3 days ago

My choice was copper sulfate + table salt + aluminum wire. Acids were hard to come by, but copper sulfate was easily available as a treatment for plants, and did not need such careful handling.

[–] aidenn0 3 days ago

If by "much stronger" you mean "less than 10% stronger"

A theoretical "vacuum filled" balloon would only be 16% more lift per unit volume than a helium balloon.