What do diamond, ketchup, and traffic jams have in common? They behave as materials — Interactions between individual constituents lead to emergent properties. The difference lies in scale of interactions. In diamond, interactions between carbon atoms determines properties such as it’s brilliance, toughness and inertness. Ketchup gets it’s consistency from sliding polymer chains. Birds organize into flocks and display awe inspiring swirls as one cohesive unit because each bird coordinates with it’s immediate neighbors. And traffic jams emerge from drivers responding to the driver in front. Read on to understand these and more everyday phenomena!