Viscosity and Density of Liquids

Definition:
- Viscosity refers to a liquid's internal resistance or friction that keeps it from flowing freely.
- It serves as a measure of how quickly a liquid can flow.
Temperature Dependence:
- As temperature increases:
- Speed of particles increases.
- Viscosity decreases (the liquid flows more readily).
- As temperature decreases:
- Speed of particles decreases.
- Viscosity increases (the liquid flows more slowly).
Fluid Behavior:
- Fluids with low viscosity:
- Flow quickly.
- Exhibit little internal resistance or friction.
- Fluids with high viscosity:
- Flow slowly.
- Have greater amounts of internal resistance or friction.
Particle Model of Matter and Viscosity:
- The particle model explains how viscosity changes with temperature.
- Liquids are composed of particles that slide and roll over one another.
- When temperature is added:
  - Particles become more kinetic and roll more rapidly.
  - Result: Decrease in viscosity, leading to easier flow.
- Conversely, when temperature decreases:
  - Particle movement slows down, increasing viscosity and leading to slower flow.

Definition:
- Density is defined as the amount of matter present in a given volume.
- Formula for density:
- \text{Density} = \frac{\text{Mass}}{\text{Volume}}
- Where mass is in grams (g) and volume can be in milliliters (ml) or cubic centimeters (cm³).
Units of Measurement:
- Density is measured in:
- g/ml for liquids.
- g/cm³ for solids.
Changes in Density:
- Density can be affected by temperature changes:
- Increase in Temperature:
  - Particles gain energy.
  - Spaces between particles increase.
  - Results in decreased density (substance becomes less dense).
- Decrease in Temperature:
  - Particles lose energy.
  - Spaces between particles decrease.
  - Results in increased density (substance becomes more dense).

Interrelation of Density and Temperature:
- Density changes with variations in temperature:
- Higher temperature leads to more space between particles, decreasing density.
- Lower temperature leads to less space between particles, increasing density.
Dependence on Particle Characteristics:
- Density is contingent on:
- The number of particles in a specific volume.
- The kind of particles present in that volume.