1. MECHANICAL SYSTEMS & CONTROL CONTENT PROGRESSION (CAPS Pg 52)
GRADE 7
TERM 1
GRADE 8
TERM 3
GRADE 9
TERM 2
Simple mechanisms; first-, second- and third-class levers.
• Mechanical advantage/disadvantage using levers (elementary qualitative treatment).
• Levers and linkages.
• Pneumatics and hydraulics used to increase human strength.
Simple mechanisms as components of more complex machines designed to provide users with a mechanical
advantage:
• Linked lever systems.
• Gears (link to term 1: spur, bevel, rack and pinion, worm).
• Gears – driver, idler, driven; velocity ratio/force multiplication.
• Belt drive and chain drive systems – chain block, bicycle or motor cycle gear cogs.
• Hydraulic/pneumatic systems.
Interacting mechanical systems and sub-systems.
• Hydraulic principles: incompressibility of liquids, pressure in liquids, force transfer.
• Hydraulic/pneumatic systems that use restrictors, one-way valves: hydraulic press/jack.
• Gear systems – spur, bevel, rack and pinion, worm.
• Mechanical control mechanisms – ratchet and pawl; cleats; bicycle brakes; disc brakes. .

2. MECHANICAL SYSTEMS & CONTROL CONTENT PROGRESSION Continue......
GRADE 7
TERM 1
GRADE 8
TERM 3
GRADE 9
TERM 2
• Mechanical advantage – including simple calculations.
• Systems diagrams.
• Belt-drive systems with more than one stage.
• Pulley systems – fixed pulley, moveable pulley, and multiple pulleys (block and tackle).
• Systems where mechanical, electrical or pneumatic systems are combined.
electronic or hydraulic or pneumatic

3. MECHANICAL SYSTEMS & CONTROL CONTENT PROGRESSION (TASKS)
GRADE 7
TERM 1
GRADE 8
TERM 3
GRADE 9
TERM 2
Task: hydraulic powered rescue equipment.
More simple mechanisms – wheel and axle, cranks and pulleys, gears.
More simple mechanisms – wedge, gear ratios, cams.
• Mechanical systems that change the magnitude of forces involved: gear ratios.
• Mechanical systems that change the rotary to linear motion: crank, cam.
Task: mine shaft headgear.
Task: identify and solve problems that can be solved by mechanical systems integrated with either electrical/
electronic or hydraulic or pneumatic.

4. CAMS
A CAM is a simple machine in which rotary movement is changed into reciprocal movement.

5. CAMS
Two or more Cams can be mounted to the same shaft to perform a duty.
In a car engine a number of Cams are mounted to a Shaft called a Cam Shaft.
A crank which is device consisting of an arm or handle that is connected to a shaft at right angles, enabling the transmission of motion to or from the shaft is usually used to control cams.
A typical application of a Cam controlled by crank in which a rotary movement is converted to a reciprocal movement is a Sewing Machine.
A more complex application of Cranks and Cams shafts is an engine of a motor car.

6. CAMS
In simpler applications, Cranks and Cams are used in the manufacturing of children’s toys.

7. Pulleys
A pulley is a wheel with a groove around the edge rotating freely around an axle.
A rope or belt fits into the groove which prevents it from slipping.
When using two pulleys and a flexible belt the main functions are:
To transfer rotary motion between two shafts; either in the same or opposite directions.
To make work easier or quicker when using pulleys of different sizes.

8. Pulleys Cont...
Pulleys can be set up in three different ways:
A single fixed pulley
A movable pulley
A combination pulley

9. PULLEYS
Pulleys are constructed like gears as they are round but the pulleys have a groove on which the belt or rope run and gears have teeth on the outside. Pulleys operate similar to the gears except that two pulleys are joined together by the belt or rope whereas most gears mesh together with the teeth although some of the gears are joined by a chain like in a bicycle.

10. USES OF PULLEYS
1. INCREASING SPEED

11. USES OF PULLEYS
2. DECREASING SPEED

12. 3. CHANGE DIRECTION OF ROTATION
USES OF PULLEYS
3. CHANGE DIRECTION OF ROTATION

13. 4. CHANGE THE AXIS OF ROTATION
USES OF PULLEYS
4. CHANGE THE AXIS OF ROTATION

14. Model to be used

15. Gears
A gear is a wheel with teeth around the edge rotating freely around an axle.
Types of gears:
Spur gear
Idler gear
Bevel gear
Worm gear
Rack and pinion

16. Functions of gears 1. CHANGE THE TYPE OF MOVEMENT (Rack and pinion)
The first function of gears is to change the type of movement. A rack and pinion (spur
gear) changes linear motion (motion in a straight line) to circular motion (rotary
motion). The pinion is fixed on a shaft. When the pinion turns, it makes the rack move in a straight line. Pulling or pushing the rack makes the pinion turn.

17. Functions of gears
2. CHANGE THE AXIS OF ROTATION AT AN ANGLE OF 90° (Bevel Gears)
The second function of gears is to change the axis of rotation. This changes the direction of rotation through 90°. Bevel gears have sloping slides so they can be used for driving shafts that are at an angle to one another.

18. Functions of gears 3. CHANGE THE DIRECTION OF MOVEMENT (Idler gear)
Driven
Driver
Driven
Driver
Idler
Driver and driven gears rotate in opposite directions.
Driver and driven gears rotate in the same direction.
When two gear wheels mesh, the driver gear turns in the opposite direction to the drivent gear. If a third gear is added in between, the driven gear will turn in the same direction as the driver gear. The middle gear is called the idler gear.

19. Functions of gears
4. INCREASE OR DECREASE SPEED AND FORCE (Worm and gear)
It is best to use a worm and gear wheel to obtain a large increase in force and a large decrease in speed. A small force turning the worm is turned into a large force turning the gear wheel. In this gear system motion between the shafts is transmitted at right angles similar to bevel gears.

20. DEMONSTRATION (20minutes)
The Changing of Gears in a bicycle to demonstrate gearing up and gearing down.
(Real mountain bike used to demonstrate that when riding at a lower gear the force increases and the force decreases with an increase in the gear size.)

21. DEMONSTRATION (20minutes)
The use of pulleys in the car engine.
(The pulley system in a car engine is demonstrated to show the increase of speed in pulley systems)

22. ELECTRICAL SYSTEMS AND CONTROLL
PROGRESS MAP (ELCTRICAL SYSTEMS AND CONTROL)
GRADE 7
GRADE 8
GRADE 9
Electrical circuit basics:
• Basic circuit components: cell(s), conductor, switch, resistor, lamp.
• Simple circuit diagrams showing various component arrangements.
Magnetism and magnetic metals: iron and steel, nickel, cobalt.
• Introduction to electromagnetism: the electromagnet.
• Recycling metals.
task: design and make a crane to carry an electromagnet to sort scrap metals for recycling
• Circuit diagrams, conventions and component symbols.
• Input devices, control devices, output devices.
• Circuit design (simple) and circuit interpretation.
• Circuits with more than one input or control device.
Electrical energy sources (including illegal connections):
• Sources of direct current: electrochemical cells; photovoltaic cells.
• Sources of alternating current: generating (thermal and alternate).
• Distributing a.c electricity: the national grid, transformers (an application of electromagnetism). Ohm’s Law: qualitative treatment.
Logic conditions:
• and logic (series); truth table.
• or logic (parallel); truth table.
task: dual switch system like an alarm circuit with at least two panic buttons in different rooms, or similar concept using either AND or OR logic conditions.
Electronic systems and control - how simple electronic circuits and devices are used to make an output respond to an input. Learners should be able to read a given electronic circuit diagram and assemble the components into a working circuit.
• Input components: electrochemical cells, photovoltaic cells.
• Storage components: electrochemical cells, capacitors.
•Control components: switches, resistors, diodes, light emitting diodes (LED), transistors
. • Sensor components: thermistors, light dependent resistors (LDR).
• Output components: lamp, buzzer/bell, light emitting diodes (LED).
• Resistor codes.
• Ohm’s Law: quantitative treatment with graphs and calculations.
task: identify a problem that can be solved by an electronic circuit. Assemble a given electronic circuit and design a device which can utilise the circuit to solve the problem.

23. ELECTRICAL SYSTEMS AND CONTROLL
Basic electrical components
PICTURE
NAME
SYMBOL
USE
Conductor
Deliver current to various parts of the circuit
Cell
Supply the circuit with electric energy.
Bulb
Converts electrical energy to light.
Switch
A device that either opens or closes the path of current in an electric circuit.
Buzzer
Changes electrical energy into sounds energy. (Rings when current flows through it)
Push button
Open or closes the path of current in an electric circuit only while it is pressed. +
Light Emitting Diode (LED)
Shows the presence of current in the circuit.

24. ELECTRICAL SYSTEMS AND CONTROLL
Basic electrical components
NAME
PICTURE
SYMBOL
Single pole, single throw (SPST)
Single pole double throw SPDT
Double pole single throw DPST

25. ELECTRICAL SYSTEMS AND CONTROLL
Basic electrical components
NAME
PICTURE
SYMBOL
USE
Light dependent resister LDR
Used as a switch in day light switches. Resistance decrease when it is exposed to light.
Transistor
Can act as a switch and is also used as an amplifier.
Capacitor
Store electric charge
Thermister
Opens the path of current in the circuit when the temperature reaches the certain value.
Diode
Make current to flow in one direction and also used to change alternating current to direct current.

26. ELECTRICAL SYSTEMS AND CONTROLL
Scenario
Scenario: You stay at home with your grandmother only. She is very old and find it difficult to walk around the house during the day as she has been diagnosed with multiple illnesses that usually attack elderly people. In summer, your house is very hot and the person of her age and state of health need to stay in a normal cool room temperature. The temperature should neither be too hot no too cold as it might pose danger to her health. The problem is that during the day when you are at school there is no one to switch the fan ON and OFF for her at regular intervals to keep the room temperature constantly cool. You therefore have to design and make an electronic devise that will help you solve this problem when you are not at home.
NOTE 1: You should first build a sample working devise that will controll the light emmiting diode in the place of an electric fan. Your electronic components should be mounted on the board and placed inside an eclosure. Your enclosure can be made of cardboards or any other simple obtainerble materials. Only the LED, Thermister and the wires to the voltage supply should protrude outside the enclosure.

27. ELECTRICAL SYSTEMS AND CONTROLL
3D OBLIQUE SKETCH OF THE CONTROL BOX

28. ELECTRICAL SYSTEMS AND CONTROLL
HEAT
SWITCH

29. ELECTRICAL SYSTEMS AND CONTROLL
The following circuit diagram should be used when mounting components to the board

30. GRADE 8 A CRANK AND CAM PROJECT
Each group should use the Technology kit to create a models of a Crank controlling two Cams that can be used to flash Stop and Go signs when the road is under repairs.

31. GRADE 9 ELECTRICAL SENSORS
Each group should use the Technology kit to create the control circuit of the electric sensor.

32. GRADE 8+9 INVESTIGATIONS OF PULLEYS
Each group should use the Technology kit to create three models of:-
1. Fixed pulley
2. Movable pulley
3. Combination of three pulleys.
The same sizes of pulleys should be used and for the investigation purpose, a spring balance as well as a 500ml water bottle should be used.

33. GRADE 9 ACTIVITY 2 (20minutes)
Different groups use the Technology kit to develop the models of the following:-
Group 1
Bevel Gears
Group 2
Rack and pinion
Group 3
Idler gear

34. ACTIVITY (COMBINATION OF SYSTEMS)
Design and make a 4 wheel drive toy car that can, at a minimum, move in a straight line and in one direction only. The car should use an electric motor to move. The following materials could be used: Spur gears with an idler gear, an electric motor, a pulley with a rubber band , SPDT switch and a 6V battery at the least. Additional materials may be used.