Newtonian vs. Non-Newtonian Fluids in Everyday Life

What They Are

Newtonian fluids are liquids that flow the same way no matter how hard they're pushed. Their thickness, called viscosity, stays the same. Examples of Newtonian fluids include water, air, and most oils.

Non-Newtonian fluids, on the other hand, change their thickness when you push them differently. This means they can act in various ways. Some, like ketchup, get thinner when you stir or shake them (this is called shear-thinning). Others, like cornstarch mixed with water, get thicker when you stir them harder (this is shear-thickening).

Newtonian Fluids

• Thickness: Stays the same.
• Flowing Behavior: Follows a simple rule called Newton's law, which explains how they act when pressure is applied.
• Where They're Used:
  • Lubrication: Oils stay reliable and perform well under different pressures.
  • Hydraulic Systems: Water and standard oils are great at carrying pressure.
  • Food Industry: Recipes often use predictable liquids like water and milk.

Non-Newtonian Fluids

• Thickness: Changes when pressure is applied.
• Different Types:
  • Shear-thinning (pseudoplastic): These become thinner when stirred (like ketchup or paint).
  • Shear-thickening (dilatant): These get thicker when stirred harder (like cornstarch in water).
  • Bingham Plastics: These need to be squeezed before they flow (like toothpaste or mayonnaise).
• Where They're Used: Non-Newtonian fluids are helpful in many ways:
  • Cosmetics: Lotions become easier to spread but stay thick in the bottle.
  • Transportation: Slurries and concrete can be thick while moving but smooth out when placed.
  • Biological Fluids: Blood changes its thickness depending on how it flows in the body.

Interesting Facts

• About 70% of liquids used in factories are non-Newtonian. This shows how important they are in making things.
• In cooking, non-Newtonian fluids help make food textures and flows just right.
• For example, ketchup can be very thick when sitting still but turns runny when shaken.

Final Thoughts

Understanding the difference between Newtonian and non-Newtonian fluids is really important. It helps engineers and scientists choose the right liquids for different tasks. This knowledge affects everything from designing industrial machines to creating new products.