Shear-thinning is a property of certain fluids where their viscosity decreases when subjected to shear stress or agitation. This means that when you stir or shake a shear-thinning fluid, it becomes easier to flow. Common examples include paint, ketchup, and blood, which all become less thick when mixed or pumped. This behavior is useful in various applications, as it allows for easier handling and application of these materials. For instance, paint can be spread smoothly on surfaces, while ketchup flows more readily when squeezed from a bottle. Shear-thinning fluids are essential in both industrial and everyday products.