So rule number one, don't let go of your balloons ... The other argument is that helium balloons are claimed to reach a height of anywhere up to ten kilometres before shattering into tiny little ...

I mean, that was kind of my number one assumption, which was grossly incorrect, actually. On a side note, the balloon market worldwide is only about 10% of the overall end use for helium.

A balloon filled with helium and one filled with hydrogen are ignited. Hydrogen provides a loud explosion and flame. He(g) + O 2 (g) → N.R. Light the candle on the end of the yardstick and lower the ...