Grade 8 Unit A: Curriculum Links | Print |

Unit A: Mix and Flow of Matter
(Science and Technology emphasis)

The materials that we us~including natural and manufactured ones~often take the form of fluids. Fluids are composed primarily of liquids and gases, but may also include solids in variety of forms. In investigating fluids, students discover that many common household materials are aqueous solutions or suspensions in which the main component is water, and learn that such diverse substances as air and oil are fluids. Students learn that the properties of individual fluids are important to their use, including such properties as density, buoyancy and viscosity of the fluid and its response to changes in temperature and pressure. The particle model of matter is introduced to help students maa:e a conceptual link between the nature of matter and the specific behaviour of fluids.

Focusing Questions:
What are fluids: what are they made of and how do we use them?

What properties of fluids, and what interaction between fluids and other materials, are important to their use?

Key Concepts

  • WHMIS symbols and nomenclature
  • particle model of matter
  • pure substances, mixtures and solutions
  • properties of fluids
  • solute and solvent
  • mass, volume, density
  • concentration
  • viscosity and flow rate
  • solubility and saturation points
  • buoyancy

STS and Knowledge Outcomes
Students will... Investigate and describe fluids used in technological devices and everyday materials
investigate and identify examples of fluids in household materials, technological devices, living things and natural environments
explain the WHMIS symbols for labeling substances and describe the safety precautions to follow when handling, storing and disposing of substances at home and in the laboratory
describe examples in which materials are prepared as fluids in order to facilitate transport, processing or use (e.g., converting mineral ores to liquids or slurries to facilitate transport, use of paint solvents to facilitate mixing and application of pigments, use of soapy water to carry away unwanted particles of material)
identify properties of fluids that are important in their selection and use (e.g., lubricant properties of oils, compressibility of gases used in tires)

Students will
... Investigate and describe the composition of fluids, and interpret the behavior of materials in solution
distinguish between pure substances, mixtures and solutions using common examples (e.g., identify examples found in households)
investigate the solubility of different materials, and describe their concentration (e.g., describe concentration in grams of solute per 100 mL of solution)
investigate and identify factors that affect the solubility and rate of dissolving of a solute in a solvent (e.g., identify the effect of temperature on solubility; identify the effect of particle size and agitation on rate of dissolving)
relate the properties of mixtures and solutions to the particle model of matter (e.g., recognize that the attraction between particles of solute and particles of solvent helps keep material in solution)

Students will
... Investigate and compare the properties of gases and liquids and relate variations in their viscosity, density, buoyancy and compressibility to the particle model of matter
investigate and compare fluids based on their viscosity and flow rate, and describe the effects of temperature change on liquid flow

observe the mass and volume of a liquid and calculate its density using the formula d = rn/v

[Note this outcome does not require students to perform formula manipulations
or solve for unknown terms other than the density]

compare densities of materials, and explain differences in the density of solids, liquids and gases using the particle model of matter
describe methods of altering the density of a fluid, and identify and interpret related practical applications (e.g., describe changes in buoyancy resulting from increasing the concentration of salt in water; observe and describe density currents)
describe pressure as a force per unit area, and describe applications of pressure in fluids and everyday situations (e.g., describe pressure exerted by water in hoses, air in tires, carbon dioxide in fire extinguishers; explain the effects of flat heels and stiletto heels using the concept of pressure)
investigate and compare the compressibility of liquid and gases

Students will
... Identity, interpret and apply technologies based on properties of fluids
describe technologies based on the solubility of materials (e.g., mining salt or potash by dissolving)
describe and interpret technologies based on the flow rate and viscosity (e.g., heavy oil extraction from tar sands; development of motor oils for different seasons; ketchup/mustard squeeze bottles)
describe and interpret technologies for moving fluids from one place to another (e.g., intravenous lines, pumps and valves, oil and gas pipelines)
construct a device that uses transfer of fluids to apply a force, or to control motion (e.g., construct a model hydraulic lift, construct a submersible that can be made to sink or float by transfer of a fluid; construct a model of a pump)