Too much air
You’ve probably heard that potato chip bags are 90% air and 10% processed bits of non-potato. Or maybe you’ve become disappointed by opening up a seemingly full bag of snacks only to find a few measly bits at the bottom. There’s a very good reason why manufacturers do this, but this doesn’t hide the fact that you’re buying air.
To prove this point once and for all, a group of high school students in Korea designed a raft out of snack bags. They hypothesized that these bags could keep you afloat and potentially save your life if you’re stranded on an island. They were right.