SECOND TERM e – LEARNING NOTES JS 1 (BASIC 7) SUBJECT : BASIC TECHNOLOGY SCHEME OF WORK:

NAME:………………………………………………………………………………………

CLASS:……………………………

SECOND TERM e – LEARNING NOTES

JS 1 (BASIC 7)

SUBJECT : BASIC TECHNOLOGY

SCHEME OF WORK:

WEEK TOPIC

1. Revision of Last Term’s Work
2. Board Practice: basic board practice: (1) setting drawing paper on the board. (ii) Sharpening pencil to conical point and knife edge. (iii) using the tee and set squares for drawing boarder lines and horizontal and vertical lines (iv) positioning and drawing the title block. (v).writing(freehand) legible letters and numerals
3. Freehand Sketching : basic freehand techniques of drawing lines, curves, circles, and irregular shapes
4. Scales and Scale Drawing: (a) reading graduation on the metric rule. (b) measuring and comparing given sizes
5. Scales And Scale Drawing(cont’d) :(c) scale drawing: (i) types of scale; full size, 1:1 (ii) reduction scale e.g. 1:5, 1:10, 1:20, 1:100, etc. (iii) enlarged scale, e.g. 2:1, 3:1, etc.
6. Woodwork Hand Tools; (a) Measuring tools; metric rule, inside calipers, outside calipers, pair of dividers, etc. (b) Setting and Marking out tools: try-square, sliding bevel, meter square, pair of compasses, trammels, etc.
7. Woodwork Tools (cont’d) (c) Driving tools; hammer; mallet and screw driver, etc. (d) Boring tools; wood brace’ ratchet brace and bradawl, etc.
8. Woodwork Tools (cont’d) (e) Holding devices; Bench hook, Bench vice, ‘G’ cramp, sash clamp, etc. (f) cutting and pairing tools; rip saw, cross cut saw, tenon saw, bow saw, dovetail saw, jack plane, smoothing plane, spoke shaves, chisels, etc.
9. Concept of Energy and Power; (a) Concept of Energy and power. (b) Definitions: (i) power (ii) energy (iii) units (c) relationship between energy and power
10. Revision
11. Examination.

WEEK: ONE

DATE:

TOPIC: Revision of last term’s work

The Teacher should use discretion, knowing areas most students are still having difficulties in last term’s work and re-teach or re-explain those areas within this week.

WEEK: TWO

DATE:……………………………..

TOPIC: Board Practice

SUB-TOPICS:

1. The instrument required for a good board practice
2. Setting Drawing Paper on the Board
3. Sharpening pencil to conical point and knife edge
4. Using the tee and set squares for drawing boarder lines and other horizontal and vertical lines
5. Positioning and drawing the title block.
6. Writing (freehand) legible letters and numerals

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: The instruments required for good board practice

The instruments required for good board practice are:

1. Drawing board and Tee-square
2. Set-square (30^o, 60^{o ,} 45^o angles)
3. Compass and Dividers
4. Protractor and French curves
5. Drawing pencils (HB and 2H)
6. Eraser and Drawing paper

Sub-Topic II: Setting Drawing Paper on the Board

Step 1: The drawing board is conveniently placed on the table with the paper on the board, leaving equal size all round, with the Tee-square edge to the left hand side.

Step 2: Place the tee-square on the paper and gently move or slide the tee-square to the top edge of the paper. Set the top edge of the paper parallel to the edge of the tee-square with the stock of the tee-square firmly against the edge of the drawing board on the left-hand side.

Step 3: Hold the paper with four pieces of adhesive tape or two metal cups to hold the paper in position at four corners.

Step 4: Gently slide the tee-square down without moving the paper.

Sub-Topic III: Sharpening of Drawing Pencils to conical point and knife edge

A well sharpened pencil is very essential to technical drawing. Pencils for lettering and freehand sketching should be sharpened to a ‘conical point’ while those for geometrical or engineering drawing should be sharpened to a ‘chisel point’.

All horizontal lines are drawn with the aid of tee-square. The set-square is used sitting squarely on the tee-square to draw vertical lines.

EVALUATION

1. Briefly explain how set-square can be used to draw vertical lines.
2. Mention five drawing instruments.

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic IV: Using the tee and set squares for drawing Lines

This is a practical topic. The teacher should DEMONSTRATE this as much as possible in class for the students

The various uses of setsquares are given below:

Types and Uses of Lines in Technical Drawing

Boarder lines are also called margins. A space of about 10-15mm is left all around the drawing paper and is demarcated with straight lines. These drawing paper are called border lines. They beautify the drawing paper and protect the drawing inside.

Sub-Topic V: Positioning and drawing the title block

Title Block: It gives necessary information about the drawing such as name of designer, school, class, date, scale etc. The title block is usually at the bottom right-hand corner of the drawing paper.

Sub-Topic VI: Writing (freehand) legible letters and numerals

Lettering is the art of writing of letters (alphabets) and numbers (figures) in bold form or lower case form on drawing.

The most important point is that the characters of the lettering must be uniform, legible, equally spaced and well proportioned. Lettering can be done either by free hand or with an instrument. The two styles of lettering are vertical or inclined styles.

The teacher should DEMONSTRATE this as much as possible with the students.

EVALUATION:

1. Mention five drawing instruments required for good board practice.
2. What type of drawing instrument can be used for drawing parallel line?
3. What is lettering?

READING ASSIGNMENT: Students should read about Board Practice

TEXT: NERDC Basic Technology for Junior Secondary Schools 1 Chapter 6 Pages 43-48.

WEEK-END ASSIGNMENT:

1. __________ is an instrument used for drawing parallel line (a) compass (b) ruler (c) divider (d) tee-square
2. Pencils for lettering and freehand sketching should be sharpened to a ______ point (a) chisel (b) conical (c) pointed (d) curved
3. ________________ are also called margin (a) leaf (b) border lines (c) centre lines (d) thick line
4. _____________ and ________ are two styles of lettering.
5. Thin continuous line can be used _______ (a) edges (b) construction lines (c) hidden outlines (d) path lines.

THEORY

1. What is title block?
2. What is lettering?

Marking Scheme

1. D (2) A (3) B (4) vertical and inclined (5) B

Theory

1. Title block gives necessary information such as designers name, title, date, scale etc of the drawing.
2. Lettering is the art of writing of letters (alphabets) and numbers (figures) in bold form or lower case form on drawing.

WEEK 3

DATE:

TOPIC: Freehand Sketching

SUB-TOPICS: (i) Definition or meaning

(ii) Techniques of Sketching

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: Definition or meaning

Freehand sketching is one of the quickest methods by which the shape of an object can be communicated to others without using any drawing instrument except a pen or a pencil. Examples of free hand sketches are:

Freehand sketching is of advantage because a good sketch reduces the amount of writing needed to describe an object.

The teacher should DEMONSTRATE general examples of freehand sketches to the students

EVALUATION

What is freehand sketching?

Name the instruments used in Freehand Sketching.

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic II: Technique of Sketching

1. Sketching a Straight line: A straight line is defined as the shortest distance between two points. We can use freehand to draw a fairly straight line by the following procedures.
2. Put a dash or dot far enough to the right-hand side of the paper.
3. Start to draw a line from the left-hand side to join the dash or dot with your eyes fixed on the point.
4. Sketching a curve: To draw a curve by freehand, it will be necessary to plot some points not too far from each other at different levels, like this ——— with the points in position attempt to draw curves by joining the dashes or dots.
5. Sketching a Circle: To draw circles, the easiest way is to draw lines which are equal in diameter to the circle in different directions. Each line must be as faint and straight as possible, each crossing one another at a central point. Now, join the points by little curves from the top of each line. Try to draw other circles by means of joining two large curves having half the size as radius and full size in diameter.
6. Sketching a Square Box: This can be sketched in an isometric or oblique view. Isometric views have the vertical height and the base lines included at 45⁰ to the horizontal while the second base line is horizontal. Once it is decided which view to represent, the block is drawn by using a series of straight lines both vertical and horizontal, applying the techniques discussed earlier.
7. Sketching an Irregular Edge – Figures with irregular edges are best drawn by first sketching a regular or square block which can completely contain the object. The shape is then carefully shaped by using dotted lines joined to show the desired shape with appropriate curves.

EVALUATION

1. Briefly describe the technique of sketching a straight line and circle.
2. What is freehand sketching?

READING ASSIGNMENT

Read about scale drawing against next lesson.

TEXT: NERDC Basic Technology for Junior Secondary Schools 1 Chapter 7 Pages 49 – 56.

WEEKEND ASSIGNMENT

1. ____________ is a shortest distance between two points.
2. A square box can be sketched in an _______ or __________

THEORY

1. What is freehand sketching?
2. State one advantage of freehand sketching.

MARKING SCHEME

1. A straight line
2. Isometric or oblique.

THEORY

1. Freehand sketching is one of the quickest methods by which the shape of an object can be communicated to others without using any drawing instrument except a pen or a pencil.
2. It reduces the amount of writing needed to describe an object.

WEEK 4

DATE:

TOPIC: Scales and Scale Drawing

SUB-TOPICS:

i) Reading graduation on the meter rule

ii) Measuring and comparing given sizes

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: Reading graduation on the meter rule

Meter Rule is a flat measuring device used to measure the length, height or width of an object. It is normally made of wood, plastic or metal. The meter rule is graduated in millimeters (mm) or centimeters (cm).

10mm = 1cm

Many kinds of meter rule are graduated between 0cm and 100cm. The straight parallel bars on the meter rule show the readings.

The teacher should DEMONSTRATE how to read the graduation on the meter rule to the students.

EVALUATION

The student should read the following points on the meter rule

1. 54.5cm
2. 72.3cm
3. 38.7cm
4. 84.2cm

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic II: Measuring and comparing given sizes

Measuring dimensions on the meter rule requires the following principles:

1. Do not take measurement directly with compass or dividers. Use the meter rule
2. Always place the meter rule along the line to be measured.
3. Always make a short dash at right angles to the meter rule during measurement
4. After setting off a dimension, always double-check your dimension to make sure that the distance is accurate
5. Small letters are used for the various units of measurement
6. For dimensions less than one, the decimal point comes after zero e.g. 0.25, 0.45, 0.85 etc
7. The units cm and mm are not written besides dimensions after measurement but a note is made on the drawing stating the unit of all the dimensions.

The teacher should DEMONSTRATE how to measure various sizes and dimensions to the students

EVALUATION

Construct a plain scale of 100m to 1m to read 3m. Indicate the following dimensions on the scale:

1. 1.15m
2. 2.45m

READING ASSIGNMENT: Students should read about: Scales And Scale Drawing

TEXT: NERDC Basic Technology for Junior Secondary Schools 1 Chapter 8 Pages 58 – 63

WEEKEND ASSIGNMENT

1. Draw a line 68mm and an equivalent of it in cm indicating the dimension in cm
2. Construct a plain scale that can be read up to 15cm and on it indicate
3. 8.4cm ii) 7.4cm iii) 0.8cm

WEEK 5

DATE:

TOPIC: Scales and Scale Drawing (contd.)

SUB-TOPICS:

(i) Scales and Scale Drawing

(ii) Materials for Scale Drawing

iii) Types of Scales used in Drawing

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: Scales and Scale Drawing

Scales drawing is different from ordinary drawing or sketching because it provides an accurate representation of the objects under consideration.

There are scales for reduction and for enlargement of the size of the object.

Materials for Scale Drawing

1. Metric Rule: This has two flat straight edges. It is usually 30cm long.
2. Scale Rules: These have three straight edges and are triangular in shape. Each edge of the scale rule is graduated and each scale designation is marked on the rule.

EVALUATION

What is Scale Drawing?

Name two materials for Scale Drawing

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic II: Scale Drawing (Types of Scales Used in Drawing)

Some objects are too big for the actual size to be contained on our drawing paper while some are too small for the parts to be clearly seen. We need to draw both of them to scale. Scale drawing is the drawing of a reduced size or an enlarged size of an object. Scale is usually given as a ratio and they are stated in the title block.

Sub-Topic III: Types of Scales Used in Drawing

A scale is used to draw or to read the sale on a drawing.

1. The full Scale/Size: In this case, an object is drawn to its size in all dimensions. Full size scale is 1:1
2. Reduced Scale Drawing: The actual size of the object is reduced in proportion to the drawing. Reduced size is used when the object is too big. Reduced scale is used when the object is too big. Reduced scale ratios are 1:2; 1:5; 1:10; 1:100; 1:1000 etc.
3. Enlarged Scale Drawing: This is used when the object to be drawn is too small to be clearly seen. Here, the normal size of the object is enlarged in proportion to the drawing. Enlarged scale ratios are 2:1; 10:1; 100:1; 500:1; 1000:1 etc. For example, 1000m:1mm means every 1000m on the drawing represents 1mm in actual size.

EVALUATION

1. Define Scale Drawing
2. What is the function of scale rule?
3. Mention two types of scales used in drawing.

READING ASSIGNMENT: Students should read about: Scales And Scale Drawing

TEXT: NERDC Basic Technology for Junior Secondary Schools 1 Chapter 8 Pages 58 – 63

WEEKEND ASSIGNMENT

1. ________ provides an accurate representation of the objects under construction.
2. Board Practice (b) Technical Drawing (c) Scale Drawing (d) Woodwork
3. _________ is the drawing of a reduced size or an enlarged size of the object.
4. Scale drawing (b) Electrical Electronics (c) Hard wood (d) Metal work
5. When the object to be drawn is too small to be clearly seen, we can use _______ scale
6. Full Scale (b) reduced scale (c) medium scale (d) enlarged scale drawing

THEORY

1. Mention three types of scales used in drawing.
2. What is scale drawing?

MARKING SCHEME

1. (i) The Full Scale/Size

(ii) Reduced Scale drawing

(iii) Enlarged Scale drawing

(3 marks each) = 9 marks

1. (i) Scale drawing provides an accurate representation of the objects under consideration. (5 marks) OR

(ii) Scale drawing is the drawing of a reduced size or an enlarged size of an object.

Total = 20 marks

WEEK: 6

DATE:

TOPIC: Woodwork Handtools: Measuring and marking out tools

SUB-TOPIC:

(i) Measuring tools

(ii) Setting and marking out tools

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub Topic I: Measuring tools

Measuring is one of the activities carried out on wood or metal in the workshop to get the accurate size of the work done. Examples of measuring tools are metric rule, inside calipers, outside calipers, pairs of dividers etc. Metal or wood has to be measured into the required lengths relevant to the expected construction before cutting and construction can be done.

Metric Rule – Is the simplest measuring tool in a woodwork workshop. It is made of metal, wooden, plastic or coiled tape rule.

Calipers are measuring instruments that are used to measure the diameters of circular shapes. There are three types of calipers.

1. Inside caliper is used for measuring the diameter of the inner parts of a circular object.
2. Outside caliper is used to measure the diameter of a cylindrical bar.
3. Odd-leg caliper is used to measure the centre lines of round bars. This caliper is also called Jenny’s Caliper.
4. Divider is similar to the actual place where it is needed.

EVALUATION

1. What is measuring tools?
2. What are calipers?

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub Topic II: Setting and Marking out tools – are try-square, sliding bevel, mitre rule, square, compass etc.

The next operation after measurements in woodwork or metalwork is marking out of the beginning and end of such measured lengths.

1. Try Square – It is used to mark lines that form a right angle. It is used to test the square-ness of an edge.

1. Sliding bevel – It is used for duplicating angles and for setting out bevels. The lines of such angles should not be 45⁰

1. Mitre square – The mitre square is also used to mark angles, particularly angle 45⁰

1. Compass – It is used to mark the arcs of a circle.

EVALUATION

1. Explain the function of try square
2. What is next operation after measurement?

Reading Assignment – Students should read about the driving tools.

TEXT: NERDC Introductory Technology for Junior Secondary School 1 Chapter 9, pages 64 – 78

WEEKEND ASSIGNMENT

1. ____ is used to mark the arcs of a circle.
2. ______ is used to measure the diameter of a circular shape.
3. Odd-leg caliper is also called ______________
4. Tools used to measure the diameter of a cylindrical bar is _________

MARKING SCHEME

1. Compass
2. Caliper
3. Jenny’s caliper
4. Outside caliper

5 marks each = 20 marks

WEEK: 7

DATE:

TOPIC: Driving and boring tools.

SUB-TOPICS:

1. Driving tools
2. Boring tools

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: Driving tools

Driving tools are used to fix nails and screws into wooden and metal materials. Nails are the iron material with a flat head, smooth stem and sharp end. Screws look like nails but they have turned or twisted stem. Screws are driven into wood with screwdrivers while nails are driven into wood and metals with the use of hammers. Hammers are driving tools that have two parts – a head, which is made of iron and a wooden handle. There are five types of hammers named according to the shape of the head.

1. Ball peen hammer.
2. Straight peen hammer
3. Cross peen hammer
4. Planishing hammer
5. Blocking head hammer
6. Straight-peen hammer is used for riveting while other end is used for shaping sheet metals.
7. Ball-peen hammer is used for general purposes.
8. Blocking head hammer has polished faces. It is used for shaping sheet metal.
9. Cross-peen hammer is used for drawing down and riveting.
10. Planishing hammer is used by panel beaters for finishing.

Driving tools also include mallets. Mallets are soft-faced hammers, as shown in the figure below:

Screwdrivers are also driving tools and they have different shapes and sizes. They are used to drive screw in and out of wood or metals. They have a long blade with a tip that can fit into the slots (grooves) in the head of the screw with either wooden or plastic handle.

1. Flat screwdriver used for screw having only one line slot on the head.
2. Star screwdriver is used for screws having a star opening on the head
3. Offset screwdriver is used whenever a straight screwdriver cannot be used.
4. Allen screwdriver is used for driving in or removing screws which have a hexagonal or square slot in their head.

EVALUATION

1. What are driving tools?
2. Mention and explain two types of hammer.
3. What are screwdrivers?

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic II: Boring tools

Boring is the act of making narrow holes in a material such as in wood or metal. Holes are bored in materials with tools called bits or drills. The boring tools are:

1. The ratchet brace: this is the tool used to hold bits of various sizes in the chucks. Some of the bits include:
   1. Centre bit: for boring shallow holes in wood.
   2. Dowel bit : used where two components are to be held together by the dowel pin
   3. Countersink bit: used to enlarge the existing holes in wood.
   4. Double twist drill: used for boring deep hole in wood.

1. Gimlet: this is the tool used for boring holes in wood before inserting small nails and screws.
2. Bradawl: this tool can be used to replace gimlets, could be used as screw-driver to insert small screws, and could also be used for forming small holes before using screws or nails in the woodwork.

EVALUATION

1. Mention two types of screwdrivers and their uses.
2. Name and explain two types of hammer.
3. Define boring tools.
4. Give 5 examples of boring tools and state their uses.

READING ASSIGNMENT: Students should read about metal work holding devices.

TEXT: NERDC Basic Technology for schools Chapter 9 pages 64 – 70

WEEKEND ASSIGNMENT

1. Explain the uses of star screwdriver.
2. What is hammer?

Marking Scheme

1. Star screwdriver is used whenever a straight screwdriver cannot be used.
2. Hammers are driving tools that have two parts head made of iron and wooden handle. (5 marks each = Total 10 marks)

WEEK: 8

DATE:

TOPIC: Woodwork tools: Holding devices, cutting and paring tools.

SUB-TOPICS:

(i) Holding devices

(ii) Cutting and paring tools.

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub–Topic I: Holding devices

Woodworking holding devices are the tools used to hold work piece on the workbench. Woodworkers work on workbenches. It is on these benches that various woodwork constructions are carried out. The centre of the bench is usually lower than its two sides. This area is called a ‘well’ and its function is to accommodate the tools brought from the tool cupboard to the bench top during operations. The tools cannot fall or roll on to the floor or on anyone’s feet because this part is lower than other area of the bench.

The fittings are:

1. Bench vice: also called fitter’s vice. It is used to clamp or to hold jobs when the following operations are to be carried out on the bench, filling, bending, tapping, cutting, assembling parts etc.

Other types of vice are:

Hand vice: used for holding work when performing operations such as drilling, riveting etc

Machine vice: It is fixed to the table of any machine tool.

The Care of the Vice

1. Always keep the vice clean.
2. The thread or the screw inside the vice should be oiled regularly.
3. Do not use the vice as an anvil for hammering a job
4. Always use hand force only to tighten the vice for holding the work piece.

1. Bench Stop – There are many types of bench stops. Some are made of wood while some are made of metals. It is a small strip of wood fixed on top of the bench. It is used to prevent wood from slipping off the bench top during planning.

2. Bench Hook – This is used for holding jobs during cutting and chiseling on the bench. At the same time, it protects the bench top.

3. The clamps

• 1. G-Clamp – This is a metal clamp used for clamping small jobs together. It is called a G-Clamp because of its shape which is in the form of letter ‘G’. The clamp is ideal for holding small pieces of wood together.

• 1. F-Clamp – This is used like the G-Clamp. The clamp is in the form of letter ‘F’.
  2. Sash-Clamp – it is a larger clamp used for holding and drawing woods tightly together when assembling or gluing work.

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic II: Cutting and Paring tools

Saws and Planes are used in cutting and smoothing wood in the workshop respectively. Saws are tools used for cutting wood. There are two main groups of saws: bench saw and curve cutting saws.

Curve cutting saws are:

1. Coping Saw – This is used for cutting curve marked lines of wood. The blades can be adjusted to cut in any direction.

1. Fret Saw – This is used to cut curves in thin wood of 8mm thick or less. It is used to cut plywood.
2. Bow Saw – is used to cut along curve marked lines but the wood has to be 50mm thick.

1. Compass Saw – It is used for cutting large interior curves.
2. Keyhole – It is used mainly for internal curves where the bow saw cannot be used.
3. Rip Saw – Is used for cutting along the grain of the wood.
4. Tenon saw – Is used for cutting shoulders to tenon and recesses in board

1. Dovetail saw – Is also similar to tenon saw but it is much shorter. It is used for cutting fine joints and also light sawing.

1. Panel Saw – Is used for sawing thin timber across the wood.
2. Cross-cut saw – Is used for cutting across the grain.

Types and Uses of planes

Bench planes are used to obtain a good, smooth surface and to get the correct size required. Bench planes are:

1. Jack Plane – It is used to smoothen or remove marks from timber. It is used to dress the surface and edges.
2. Trying plane – It is used to produce flat surface and perfectly straight edges.
3. Smoothing plane – It is used for clearing the surfaces and edges of timbers ready for assembling.
4. Block plane – It is used for planing small work that is not easily accessible.
5. Spoke shave – This is an example of a curve cutting plane used to produce smooth curve surfaces and edges.

EVALUATION

1. Explain the three types of clamp
2. Explain the structure of a workbench
3. What is the main use of a saw?
4. Mention 8 curve cutting saws

READING ASSIGNMENT – Students should read about concept of energy and power

TEXT: NERDC Basic Technology for Junior Secondary School 1 Chapter 9, Pages 70-78

WEEKEND ASSIGNMENT –

1. _________ is used for holding jobs during cutting and chiseling on the bench
2. _________ is used to prevent wood from slipping off the bench top during planning
3. _________ is made of cast iron, it is used to hold work piece securely while working
4. _________ is ideal for holding small pieces of wood together
5. ________ is used for holding and drawing woods tightly together when gluing work

THEORY

1. List three different types of clamps you know.
2. Mention three fittings in work bench.

MARKING SCHEME

1. Bench hook
2. Bench stop
3. Vice
4. G-clamp
5. Sash-clamp

WEEK: 9

DATE:

TOPIC: Energy and Power.

SUB-TOPICS:

(i) Concept of energy and power.

(ii) Forms of energy

(ii) Relationship between energy and power.

Content Development (NOTES FOR FIRST LESSON/PERIOD ONE)

Sub-Topic I: Concept of energy and power

Energy is defined as the ability to do work. Energy is not something we can touch or see. We can only see its effect. The standard unit for measuring energy is the Joule (J). It can also be measured in KiloJoule (KJ)

The following are the properties of energy:

• Energy exists in different forms. E.g. heat, chemical, kinetic etc
• Energy can neither be created nor destroyed.
• Energy can be converted from one form to another.eg electrical to heat as in pressing iron, chemical to heat as in gas cooker, etc

The concept of power is a scientific concept which makes it possible to rate appliances, machines and engineering system as regards to how they use energy or perform work. The concept of power can be specified as:

Electrical power: relates to electrical and electronics appliances and equipment. It is the rate at which electrical energy is consumed. It is measure in Watt (W).

Mechanical power relates to machines and mechanical system. Basically

Power = Energy

Time taken

Energy is used in the following ways:

Sub-Topic II: Forms of Energy

The major forms of energy are:

1. Heat energy: This is the form of energy which leads to the rise in temperature of a body. It can be obtained from burning fire wood, coal, gas, kerosene e.tc. The heat generated from these sources is used mostly in cooking.
2. Mechanical energy: This is the energy of motion or potential for motion. Mechanical energy is used by falling objects, flying objects, flowing objects. There are two types of mechanical energy. These are :

Kinetic energy: energy possessed by a moving object. A hammer descending on a nail to drive it into wood has kinetic energy.

Potential energy: energy a body possesses because of its position. A body at a high position has higher potential energy than a body at a low position.

1. Electrical energy: this is the energy we use to operate electrical appliances like fans, radio, television set, electric irons etc. we obtain electrical energy from Power Holding Company of Nigeria which supplies electrical energy to our homes. We also obtain electrical energy from generators we use in our homes, batteries.
2. Chemical energy: this is the energy stored in chemical substances like food, kerosene, wood, animal dung, sawdust, etc. The chemical energy in the food produces muscular energy which keeps us going.
3. Sound energy: sound energy stimulates our ear and vibrates the air. Sound is energy because it vibrates the air and the vibrated air strikes our ear, which hear the sound.
4. Light / Solar energy:

Light / solar energy comes from the sun, which releases the energy through its rays. Solar energy from the sun dries clothes after they are washed. Without solar energy, photosynthesis cannot occur, without photosynthesis plants cannot grow, and without plants, human beings cannot and animals will not have food. Solar energy generates heat.

1. Nuclear energy: this is used to generate electricity in a nuclear power generating station. However, nuclear energy is very dangerous if not controlled. It can cause harm to both animals and plants. Hence nuclear power stations are not common.

EVALUATION

1. Define the term energy.
2. State the three properties of energy
3. Mention six major forms of energy
4. When fuel is burnt, the form of energy released is ———

Content Development (NOTES FOR SECOND LESSON/PERIOD TWO)

Sub-Topic (III): Relationship between energy and power

Work: Work is done when energy is used. To say that work is done means that a force has been used to move something through a distance. The force applied determines the amount of work done and the distance moved in the direction of the force. Work (w) is then a product of force (f) and distance (d).

It can be expressed as W = F x d.

The unit of force is Newton (N) while distance is measured in Newton metres (Nm) which is also called joule (j).

Power: is the rate at which work is done.

Power (P) = work done

Time taken

Power is measured Watt (w)

Example: A man lifts a load of 50kg from the ground to a height of 6metres within a time lift of 5 seconds. Calculate (i) the work done by the man.

(ii) The mechanical power consumed in lifting the load. Assuming g = 9.8m/s

SOLUTION

1. Work done = force x distance

= 50 x 9.8 x 6

=2940 joules

=2.94KJ

1. Mechanical Power = work done

Time taken

= Force x distance

Time

= 50 x 9.8 x6

5

= 588watt.

EVALUATION

1a. List four forms of energy.

b. What is energy?

1. What is power?

2. Mention four sources of energy

READING ASSIGNMENT – Students should read over all the topics that have been thought for the preparation of their examination.

WEEK 10-12: Revision and Examination