In this unit you will look inside machines like a mechanical engineer! You will learn that a mechanism is the group of moving parts inside a machine, find the input and output of mechanisms such as bicycles and egg beaters, and describe the purpose of each part. You will name four kinds of motion (linear, rotary, reciprocating and oscillating) and see how axles, gears, chains and belts transmit motion from one part to another.
Then you will dig into pulleys and gears. You will build pulley systems and count rope sections to predict how much force they save, predict which way every gear in a gear train turns (meshing gears turn opposite ways!), count teeth to work out speed, and meet mechanisms that transform motion, like the rack and pinion, the cam, bevel gears and the worm gear. You will measure how machines change forces and learn the big trade-off: less force means more distance.
Finally, you will assess how machines affect people in different communities, including jobs in the skilled trades, robots and automation, and technologies from Inuit and Métis communities, compare the environmental impacts of machines that do the same job, and design and build your own lifting machine.
Remember from earlier grades: In Grade 2 you met the six simple machines, and in Grade 3 you studied forces and strong, stable structures. Grade 4 goes inside machines to see how their mechanisms work.
Every lesson has a hands-on activity using things from home, lots of practice and a short quiz.
Curriculum expectations covered: D1.1, D1.2, D2.1 to D2.5 (Ontario Science and Technology, Grade 4, 2022, Strand D: Machines and Their Mechanisms), with STEM skills and connections from Strand A (A1.1, A1.2, A1.3, A1.4, A1.5, A2.1, A2.2, A3.1, A3.2, A3.3).