Acetylene-filled balloons explode - GIF

[DIYSwede]

Acetylene is heavier than air, its probably methane / natural gas.

Nope - acetylene is 10% lighter ( than air) at 1,095 kg/m3 @ 16 C and 1 Bar.
Density of air at 20 C and 1 Bar, is between 1,1934 @ 0% RH and 1,2039 @ 100% RH

For most practical uses: ρ = 1,25 kg/m³

Ignition was probably caused from static electricity potential differences between the balloons and/ or their respective holders.

2 cents & Cheers
Johan

[cmarlow]

I think if you look at the .08 time on the clip you see the person with green balloons walk them into the lights and the explosion propagated from where they contacted the hot lights.
I worked once where a company was setting up oil storage tanks for an oil refinery. In the bottom of the tanks was about 2 feet of water from rain and snow. Some of the welders decided to inflate balloons with welding gases. Some were acetylene, some were oxygen. The acetylene balloons would explode if hit with a spark and release a big ball of flame.
The balloons with just oxygen would randomly detonate on their own with a loud flash and bang. It seems the oxygen would saturate the rubber and as the rubber weakened it would burst. When the balloon burst it released enough energy through the rest of the oxygen saturated rubber skin for the rubber to detonate like a high explosive. The oxygen filled balloons were more dangerous than the fuel filled balloons and it took months for them all to explode because nobody wanted to be trying to collect and dispose of them.
Imagine working inside of a 200 foot diameter round steel tank where every now and then, randomly, something would explode with as much noise as a stick of dynamite would have.

[Liquidhandwash]

Nope - acetylene is 10% lighter ( than air) at 1,095 kg/m3 @ 16 C and 1 Bar.
Density of air at 20 C and 1 Bar, is between 1,1934 @ 0% RH and 1,2039 @ 100% RH

For most practical uses: ρ = 1,25 kg/m³

Ignition was probably caused from static electricity potential differences between the balloons and/ or their respective holders.

2 cents & Cheers
Johan

I don't know about the numbers But when i was a kid I filled a ballon with acetylene and it fell to the floor fastest then an air-filled ballon. My friend stupidly put a match to it and burned off his eyebrowes

[hemmjo]

I don't know about the numbers But when i was a kid I filled a ballon with acetylene and it fell to the floor fastest then an air-filled ballon. My friend stupidly put a match to it and burned off his eyebrowes

It is possible this apparent discrepancy of density of acetylene may be caused by the balloon itself. The pressure inside a balloon is a bit higher than 1 Bar due to the elasticity of the balloon itself and how much it is inflated.