Once upon a time (when I was about your age) beverage cans were made of steel, were opened with a virtually extinct apparatus known colloquially as a "church key", and were crushed in the bare hand as a macho demonstration of strength. Today almost all beverage cans (>77 billion of them per year in the U.S.) are made of thin walled aluminum and can be mangled by infants. Since aluminum is more expensive than steel, why the change? Is it progress?