The ability to flow is a key characteristic of fluids
Some solids appear to flow (ex. salt, sand) because the of the small grains but those grains have a definite shape
Some solids (like ice in glaciers) are considered fluids because they exhibit fluid-like behaviour when subjected to strong forces over long periods of time
Laminar flow is a smooth pattern of flow
Turbulent flow is an irregular, mixing flow pattern
Laminar flow along vehicles reduce resistance (drag) and makes the vehicle more efficient