When we explore fluid mechanics, it's important to know about fluid properties like viscosity and density. These properties help us understand how fluids behave in different situations.

Viscosity:

• Viscosity is a measure of how thick or thin a fluid is. You can think of it as how easily a fluid can flow. For example, honey has high viscosity, so it flows slowly. On the other hand, water has low viscosity and flows easily.
• Viscosity also changes with temperature. When the temperature goes up, liquids usually become thinner and flow more easily. However, gases tend to get thicker when heated. This information is helpful for engineers when they choose fluids for different tasks.

Density:

• Density tells us how much mass a fluid has in a specific amount of space. It is often measured in units like kilograms per cubic meter (kg/m³). Density helps us figure out if a fluid will float or sink in another fluid.
• For example, oil is less dense than water, which is why it floats on top. This idea is important for understanding how things behave in liquids.

Fluid Classification:

• Fluids are usually divided into two main categories based on their viscosity and how they act: Newtonian and Non-Newtonian fluids.
  • Newtonian Fluids: These fluids have a constant viscosity, no matter how much force is applied. Examples include water and air.
  • Non-Newtonian Fluids: Their viscosity changes depending on how much force is applied. A good example is ketchup, which flows more easily when you shake the bottle. Slurries are another example of non-Newtonian fluids.

Understanding viscosity and density is important for many things, like designing pipelines or predicting how a fluid will act in nature. In short, knowing these properties helps us work better with fluids in engineering and environmental situations.