Among syrup, water, milk, and apple juice, the most viscous liquid is syrup.

Quick Scoop

Viscosity means how strongly a liquid resists flowing; thicker liquids have higher viscosity. In everyday terms:

  • Water is very thin and flows easily, so it has low viscosity.
  • Apple juice is close to water, just slightly thicker because of dissolved sugars.
  • Milk is a bit thicker than water due to fat and proteins but still fairly runny.
  • Syrup (like corn syrup or table syrup) is much thicker and pours slowly, so it has much higher viscosity than the others.

So, if you lined them up in order from least to most viscous, it would be:

water → apple juice → milk → syrup.

Answer: Syrup is the most viscous.