A cow burps and farts between 160 to 320 litres of methane per day. Methane is lighter than air and is also odorless, so for the fart to pass over the frog pond, there would have to be a breeze. Luckily, there was one that day. It was also lucky that basically we just smelled (and listened to) the frog pond. This NFT is the smell of the Cow Fart passing over the frog pond.