Grade 9 Tech. Module

Grade 9 Tech. ModuleGrade 9 Tech. ModuleGrade 9 Tech. ModuleGrade 9 Tech. Module

Unit 2-Basic skillsUnit 2-Basic skills

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IntroductionIntroduction

• Topic 1: Energy Conversion• Topic 2: Measuring Energy• Topic 3: Schematics and Pictorials• Topic 4: Fabrication

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Topic 1 Topic 1 Energy Conversion and Energy Conversion and

TransmissionTransmission

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Mass is a measure of the amount of matter in an object and is measured in kilograms (Kg).

The mass of an object can be determined using an equalarm balance.

Activity - Measure the mass of the provided objects. Record the results in a table

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Force is the measurement of influences that change the direction of an object.

Force can be measured using a spring scale calibrated in Newtons.

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Activity

- Measure the weight of an object using a spring scale.

- Measure the force required to pull the object across a surface.

- Record the results in your table

- Describe how the mass of an object and the force required to lift the object or drag it across a surface are related.

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Activity - Measure the mass of the provided objects.- Record the results in a table

Object Mass (Kg) Weight (N) Force to pull (N)

T -Square

Yellow tape

Orange tape

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Work occurs when energy gets transferred from one object to another object.

The mathematical relationship is: W=F×dW=F×d

A few points:

• The mass has to move for work to be done on the object.

• The mass has to move in the direction of the applied force.

• Weight is equivalent to force of gravity.

• The spring scale should be parallel to the surface when pulling the object across the table.

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W=F×dW=F×d (measured in N.m or Joules)

Activity Activity

Part ADetermine the work done in pulling an object across a horizontal surface.

- Measure the force to pull the object (F)- Measure the distance you pulled the object.

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W=F×dW=F×d (measured in N.m or Joules)Part BCalculate the work done when the mass is lifted through a distance

- Measure the force to lift the object (F)- Measure the distance you lifted the object.

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Example 1:

How much work is done by a person who uses a force of 30 N to move a grocery buggy 5 m?

Given: F = 30 N d = 5 m W = ? Solution: Use W = F x d

W = F x d = 30 N x 5 m

AnswerW =  150 J

Example 2:

55, 000J of work is done to move a rock 25m. How much force was applied?

Given W=55,000 Jd=25mF=? In this problem, we are looking for force, so the equation must be rearranged.

EquationF =  W  =  55,000J  =  ?        d           25m 

AnswerF = 2200J

Handout: Practice exercise - work

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Topic 2 Topic 2 Measuring Energy and Measuring Energy and Energy TransmissionEnergy Transmission

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Voltage (V) is the difference in electric potential or the total charge between the two terminals.

Current (I) is the rate at which the electric charges move through the conductor.

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Power (P) is the rate at which work gets done.  In the case of electricity, we say that electrical power is the rate at which electrical energy is transferred by an electric circuit.

Electrical Energy (E) is the scientific form of electricity, and refers to the flow of power or the flow of charges along a conductor to create energy.

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Electrical power (P) is defined as:

Electrical Power = Voltage x Current

or, substituting the symbols

P = VxI (watts)

ActivityUse a multimeter to measure the current and the voltagebeing used by a small bulb . Calculate the power of the bulb.

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The mathematical relationship is:

Energy = (current × voltage) × time

Energy = VIt or E = Pt (Joules)ActivityUse a multimeter to measure the current and the voltagebeing used by a small bulb over a given time. Calculate theenergy used by the bulb.

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Example 1: You have an electric heater in your room.  If it operates at 220 volts and consumes 10 amps of electricity, what is its power rating? 

Given:Given: V = 220VI = 10AP = ?

Solution: Use the formula, P = IV

P = VIP = 220V x 10AP = 2200W (W is the same as watts) 

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Example 2:

How much electrical energy (E) is consumed by a 2200 W electric heater if it is turned on for 12 hours?

Cost = kilowatt x hours x cost/kwh

Given: P = 2200 W = 2.200 kilowatts = 2.20 kwT = 10 hrsCost/ kwh = $0.10

Cost = 2.20 kw x 10 h x $0.10/kwh = $ 2.20

E = P x t E= 2200 W x 43200 sec = 95,040,000 W-s or 95,040,000 Joules

How much money do you think it might cost?

If you check your "power" bill you will find that the unit used to measure the amount of electricity used is the kilowatt-hour and not joules.

To determine energy cost you must change Joules to Kw-hr

1 Kw-Hr = 3,600,000 Joules

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In our heater example we use 95,040,000 Joules of energy.

95,040,000 ÷ 3,600,000 = 26.4 kw-hr

Currently, depending on where you live, a kilowatt-hour costs about $0.09 (9 cents).

So our heated used $0.09 x 26.4 = $2.40

Not much… But in a year it adds up.

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All appliances, when new, must have a sticker attached that indicates some of the electrical properties of the unit.

Look at the sample appliance sticker below. Circled in red is important electrical information.

We can use this information to calculate the energy cost as we did in the last example!

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Power is the measurement of how fast work is done.

We can also write power as:

Power = work divided by time (work in joules, time in seconds, power in watts).

P=W ÷ t

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Example

A crane lifts a 200N crate out of a 6 meter deep hole . If it takes 5 second to complete the task, how powerful is the cranes engine?

Given: F=200Nd=6mt=5s

Solution W=fxd P=W ÷ tW=(200)x(6) = 1200 J P=(1200) ÷ (5)

P=240 Watts

Worksheet: Power and energy

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Systems that use energy to do work are not 100% efficient.

Some of the work input is turned into undesired forms of energy such as heat and sound instead of useful work.

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Only about 15% of the energy from the fuel you put in your tank gets used to move your car down . The rest of the energy is lost to engine and driveline inefficiencies.

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At the power plant, some 60 percent of the energy is lost as waste heat. Another 10 percent is lost in electricity lines and transformers before the electricity even reaches your home.

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The efficiency of a system is mathematically determinedby the ratio of work output to work input expressed as a percent

Efficiency = (work output ÷ work input) × 100%

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Example A winch use 120J of work to lift a 10N weight 8m high. How efficient is it?

Given: Work (in) = 120 JWork (out) = ?Efficiency=?

Solution: Work (out) = Fxd = 10x8 = 80J

Efficiency = (work output ÷ work input) × 100% = (120 ÷80) x 100% = 67%

The winch is 67% efficient.

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Grade 9 Tech. ModuleGrade 9 Tech. ModuleGrade 9 Tech. ModuleGrade 9 Tech. Module

Topic 3 SchematicsTopic 3 Schematics

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A schematic is a diagram that represents parts of a system using, symbols rather than realistic pictures.

You should know some of the common Electrical symbols

cell

battery

lamp

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LED

resistor (load)

switch

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ammeter

voltmeter

variable resistor

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Can you draw the schematic?

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Pictorial DrawingsPictorial DrawingsPictorial drawings are three dimensional drawings that look similar to a picture.

There are two basic types. They are:

- Oblique

- Isometric

IsometricIsometricThe isometric drawing is most commonly used when constructing a set of drawings.

Notice, front and side are at 30 degrees to the vertical.

IsometricIsometricThe faces of isometric are labeled by their location.

OrthographicsOrthographicsOften the faces are drawn separately when developing a drawing… this is called an Orthographic.

An Orthographic projection is a series of drawings that show various views of the object.

Sample Orthographic Sample Orthographic DrawingDrawing

Orthographic drawing of a book

ActivityActivity

Part 1 - Software- Isometric Drawing Tool

http://illuminations.nctm.org/ActivityDetail.aspx?ID=125Handout: Illuminations Isometric Views

Part 2 - Building with blocks.Examine objects.

•Sketch the Orthographic for each.Examine an orthographic

•construct the object using the blocks

Production MethodsA number of methods are use to produce

products.

These may include:

1. Separating

2. Combining

3. Forming

4. Conditioning

5. Finishing

Examples

1. Separating– use of a knife, chisel, plane, or saw to cut

(separate) materials

2. Combining– use of a nail, screw, staple, or glue to

combine materials.

3. Forming– Use of heat and steam to form or shape

materials

4. Conditioning – Use of chemicals to condition or

protect materials

5. Finishing– Use of sandpaper, buffing compound, or

paint to smooth and/or ‘beautify’ a project

Class DiscussionClass Discussion

View the objects on the next few slides and determine which production methods would be used to produce the product.

Remember:• Separating• Combining• Forming• Conditioning • Finishing

Grade 9 Tech. ModuleGrade 9 Tech. ModuleGrade 9 Tech. ModuleGrade 9 Tech. Module

Topic 4: Tools and MachinesTopic 4: Tools and Machines

The ToolsThe Tools

A variety of tools may be used to aid the production process.

The next few slides we will examine some common tools used for each process. See how many you can name.

Tools

• Separating

• Combining

• Forming

• Conditioning

• Finishing

Tool use and SafetyTool use and SafetyOne of the largest safety concern that cause accidents in the

lab is improper tool use.

It is important to use tools both appropriately and for its intended use.

Before any student may enter the shop he/she must review safety and proper use of every tool.

In the next unit we will review all safety requirements for the shop.

And remember it’s no good to learn it if you don’t practice it.

An overview of tools in our shopAn overview of tools in our shop

Machine Drill :Used for drilling holes through a range of materials

• There are two types, the bench drill and the pillar drill. • Important to use the correct bits.

Forstner Bit

Twist Bit

Hole Saw

Fret Saw (Scroll Saw): Used to cut and shape light materials such as, MDF and plywood.

• The general rule: the thicker the material, the slower the machine operator pushes the work against the blade.

• The blade is always set up with the teeth pointing downwards

Jointer: Used for jointing a surface or edge• Uses jointer only with the guard in place.• Joints in direction of grain.• Makes several multiple thin cuts rather than one heavy cut.

Planer: Used for surfacing a workpiece

• Planes in the direction of the grain.• Never looks directly into the front or rear opening of the

planer when it is in operation.

Band Saw: Used to cut and shape light material

• Guide the work slowly; do not force the work.• Avoid backing out from cuts • Do not attempt to cut smaller radius than the blade will

allow.

Sliding Compound Mitre Saw: Makes Standard mitre cuts (90, 45. 22.5 degrees) and Compound mitre cuts (horizontal and vertical angle adjustment).

• Repeat cuts using a stop to reproduce exact length• Waits until saw comes to a complete stop before

removing workpiece.

Lathe: Used to make spindles

• Rotates spindle by hand to check clearance before starting.• Stands to one side when starting the lathe.• Selects the appropriate cutting tools.

Hand Router• Pattern routing with upper or lower bearing bit• Edge routing with router fence• Through dado or rabbet routing with guides• Plunge base routing

Drum Sander• Grinding• Sharpening• Waits until the grinder has reached full rotational speed

before placing the workpiece against the wheel.

Table Saw• Ripping• Crosscutting

Class Discussion:Class Discussion:

Observe the objects on the next few slides and determine which power tools were used to create that product.

Safety should be a part of the shop culture. Everyone working in or visiting a shop environment has a responsibility to be constantly on guard, to identify actual and potential hazards, and to use personal protective equipment in the shop.

Discussion:

Can you list some general shop safety rules?

• What Kinds of things should you look out for in the Shop?• What Kinds of things should you look out for when using tools

*See Handout: Shop Safety Rules Shop Emergency plan

Students should be aware of any adverse reactions or allergies that they may have to sawdust, wood, metals or plastics or any medical condition that could cause a problem when handling machinery.

Make sure you disclose this information to your teacher. It would also be a good idea to inform members in your group so they can help minimize conditions that may cause reactions.

Safety EquipmentSafety Equipment

Safety EquipmentSafety Equipment

Safety Equipment we will use in our shop:

• Footwear• Safety glasses• Gloves• Face shields• Ear protection• First aid kit• Fire extinguisher• Dust Vacuum• Ambient Air Cleaner• Apron• Eye Wash

You must understand the correct use and/or proper fit for each item.

Foot WearFoot Wear

No open toed shoes

Eye ProtectionEye Protection

GlovesGloves

Steel Mesh

Kevlar

Ear ProtectionEar Protection

First Aid KitFirst Aid Kit

Fire ExtinguisherFire Extinguisher

Dust VacDust Vac

Ambient Air CleanerAmbient Air Cleaner

ApronApron

Eye WashEye Wash

Your BrainYour Brain

Students must be fully aware of the Emergency Procedures in the shop.

Know:

• Information on the Shop Emergency Plan (handout)

• The location of First Aid kits, eyewash stations, and emergency exits

Handout: Shop Safety PledgeShop Safety sheet

Quiz: Shop Safety

It’s no good to learn it if you don’t It’s no good to learn it if you don’t practice it.practice it.

See if you can spot the hazards on the next few slides.