Topic 3

• • Viscosity: how quickly a fluid flows. This is determined by a fluid’s internal resistance or friction that keeps it from flowing. The greater the friction or rubbing between particles in any fluid, the HIGHER the viscosity
•  the warmer a fluid, the faster it will flow (the lower the viscosity), this is because when energy or heat is added to a liquid, the particles slide and roll more quickly.

  As temperature decreases the particles slow down and the viscosity increases
• Flow rate is a quantitative measurement and can

  be calculated by:

        Flow Rate = volume/time

        Flow Rate = distance/time
• Density: the amount of matter in a given volume. The density of a fluid or any other kind of substance depends on the particles it is made of
• • Density depends on whether the object is solid, filled with air pockets, or something in between. If one substance is LESS dense than another, it will float on top of the MORE dense substance
• • Density is calculated by dividing the mass of a substance by its volume.
• Density does not change as long as temperature & concentration remain constant. If one of these changes, density will also change
• Water on the surface of a lake is usually warmer than water further below the surface. This is because of density. The warm water floats on the cold water because it has a lower density than cold water
• • According to the particle model, substances move more quickly when energy is added
  • The more particles move, the more space between each particle
  • As a solid changes to a liquid & eventually a gas, the particles move faster and faster
  • The more space between particles, the less dense it becomes
• • when a substance is heated It changes state
  • At a low temperature, it will be a solid
  • At a medium temperature it will be a liquid
  • At a high temperature it will be a gas
• •  most substances have a greater density in thier solid state than in their liquid or gas state

  Less space between particles at a solid state than at a liquid or gas state
• • Dissolving one substance (salt) in another (water) increases the number of particles in a given volume
• • Because of density variations in the world’s oceans and rivers, all cargo ships have what is known as a plimsoll line painted on their hulls
  • The line shows how heavily a ship can safely be loaded in different water conditions
• • Density does not change as long as temperature & concentration remain constant. If one of these changes, density will also change
• • Water on the surface of a lake is usually warmer than water further below the surface. This is because of density. The warm water floats on the cold water because it has a lower density than cold water
• • According to the particle model, substances move more quickly when energy is added
  • The more particles move, the more space between each particle
  • As a solid changes to a liquid & eventually a gas, the particles move faster and faster
  • The more space between particles, the less dense it becomes
• • As particles become more active, they move away from each other and the space between them increases
  • This causes the volume to increase, but the number of particles remains the same
  • With the same number of particles in a larger volume, the density decreases
• • Buoyant Force: an upward force exerted by the liquid
• • The buoyant force of the liquid on the object is greater than the force of gravity pulling down on the object
  • The object FLOATS!
• plimsoll line: The line shows how heavily a ship can safely be loaded in different water conditions
• compression: When a force pushes on an object, the object is said to be under compression

  • Objects under compression tend to deform in shape
• liquid is the lest compressible, gas is the most. solids can be compressed
• • Pressure: The measure of the amount of force applied to a given area
• The Greater the Depth, The Greater the Pressure
• • Pascal’s Law- when force is applied to a liquid in an enclosed container, the pressure and is transmitted equally in all directions throughout the liquid. Because of this, technologies like hydraulic and pneumatic devices were created
• hydolic lifts / devices: They use 2 pistons of different sizes to create pressure

  • A piston is a disk that moves inside a cylinder
  • The small piston is the input piston, which pushes down on the liquid to create pressure
  • This pressure is transmitted through the liquid where it pushes up on the large piston, which is the output piston
  • one of the benefits of a hydraulic system, In order to move the large piston, the small piston must move farther than the large piston
• • Pneumatic Device system that uses a gas under pressure to move loads