What are the best examples of a really good design?
Not Coca-Cola, but the vessel in which it is contained: The aluminum beverage can.
Let’s begin with the shape of the can. The cylindrical shape is beneficial for several reasons:
- There are no corners or edges, which means that there are no weak points at which pressure could build up and lead to a rupture in the can.
- It is comfortable to hold in one’s hand and feels perfectly natural to drink from.
- A cylinder has a packing factor of 91%, meaning that when the cans are packed in boxes for shipment, 91% of the available space is taken up by the can, while only 9% of the volume is empty space. This contributes to efficient packing and delivery of the beverage.
- A domed bottom allows the can to stand on its own and to withstand greater pressure than if the bottom were flat.
But the tab might even be more brilliantly designed.
When first lifting the tab, it acts like a 2nd class lever, where the load (the rivet, in this case) is between the effort (the tab) and the fulcrum (the end of the tab). This is like lifting a wheelbarrow.
But the moment the rivet is lifted even the smallest amount, the can vents (dispels gas, i.e. releases pressure), the tab switches to a first class lever, where the rivet becomes the fulcrum, and the tip of the can becomes the load, which can then pop open the can.
This setup also allows the tab to remain attached to the can, which decreases littering.
Those are just two of the reasons the aluminum beverage can is a feat of engineering ingenuity. For a more detailed yet very understandable explanation, check out Professor Bill Hammack’s(which is where the images in this post are taken from).