The Incredible Aluminum Can

It's a big accomplishment for any design to reach that level of maturity where it quietly does its job perfectly and reliably to the point where it becomes almost invisible. The aluminum beverage can has gotten there, and it's allowed us to forget all the amazing design and engineering that went into it. "Engineer Guy" Bill Hammack does a wonderful summary video, explaining among other things the genius of the modern pop top. Personally, I didn't know that it starts as a 2nd-class lever to pull out and break the can's seal (much easier than pushing into the pressurized can), then automatically changes to a 1st-class lever when that pressure is released to bend the tab out of the way. Just that little bit of engineering has prevented untold numbers of removable pop-tops from becoming sharp and dangerous litter. If you want to learn more, the video is well worth 11:38 of your time!
[via Gizmodo]