Planning Index: Mechanical Systems | Print |

Grade 8 Science Unit Plan
Unit D - Mechanical Systems
(Science and Technology Emphasis)

Grade 8 Unit Overview (Alberta)
Machines are used for many purposes in our daily lives, when we need to transfer energy into motion, or move materials in a controlled way. in learning about mechanical devices, students investigate how components are linked so that energy is transferred efficiently and desired functions are performed. A comparison of past and present technologies helps students recognize that different approaches have been used over time to meet common needs. Evaluation of efficiency, effectiveness and impacts on daily life, the community and the environment are important considerations in this unit.

Concepts Covered and Developed through Instruction

  • design and function
  • systems and subsystems
  • simple machines
  • transmission of force and motion
  • mechanical advantage
  • speed ratios and force ratios
  • measurement of work in joules
  • mechanical advantage and hydraulics

What do the students know?

 How do students think energy is transferred in a machine?
Can they describe mechanical systems according to their function, mechanical advantage and efficiency ?

What must they Learn?

How energy is transferred in mechanical devices and how these devices provide for the controlled application of energy in ways that are efficient, effective and responsible?


Specific Learner Outcomes

Instructional Focus

Focus 1

Timeline of Machines

Illustrate the development of science and technology by describing, comparing and interpreting mechanical devices that have been improved over time


- water moving devices
Persian wheel, Archimedes wheel, mill wheel )
- lifting devices
- trial and error

Textual resources / Research

Lab Activities / Demonstrations
Problem solving

Focus 2

Simple Machines

Analyze machines by describing structures and functions of the overall system, the subsystems and the component parts


- analysis of a device
- function of the device
- subsystems
- types of simple machines
- energy source
- gears, belt drives

Scientific Illustrations
Lab Activities / Demonstrations
Building a Model
Textual Resources / Research
Textual Resources / Research
Lab Activities / Demonstrations

Focus 3

Force and Speed

Investigate and describe the transmission of force and energy between parts of a mechanical system analyze mechanical devices to determine speed ratios and force ratios


- turning ratios
- efficiency (
- work input/output
- fluid pressure
- Pascal's Law
- pressure formula
- hydraulic jack
- technologies

Building Models
Problem Solving Activities
Problem Solving Activities / Calculations
Lab Activities
Textual / Audio-Visual Resourses
Problem Solving Activities / Calculations
Lab Activities
Textual Resources / Research 

Focus 4

Technology and Machines

Analyze the social and environmental contexts of science and technology, as they apply to the development of mechanical device


- evaluation of design
- criteria
- reciprocal influences

Building an evaluation model
Case Study