UNIT D ELECTRICAL PRINCIPLES & TECHNOLOGIES
Science 9
LEARNING GOALS
Investigate and interpret devices that convertvarious forms of energy
Describe technologies for the transfer andcontrol of electrical energy
Identify and estimate (using calculations)energy inputs and outputs for various devicesand systems
Evaluate the efficiency of energy conversions
Describe societal and environmentalimplications of the use of electrical energy
SKILLS GOALS
Ask science-based questions
Design an experiment when given a question
Conduct an investigation
Analyze and interpret my qualitative andquantitative data
Work collaboratively with my peers
ATTITUDE GOALS
Show interest in science
Appreciate how different ideas from all overthe world mix together to bring aboutunderstanding
Take my time and consider variousapproaches to investigations, problems andissues
Begin to recognize my impact on theenvironment
Work safely in the science classroom and lab
FOCUSING QUESTIONS
How do we obtain and use electrical energy?
What scientific principles are involved?
What approaches can we use in selecting,developing and using energy-consumingdevices that are efficient and effective in theirenergy use?
CONCEPT 1 VOCABULARY TERMS
Energy
Chemical energy
Thermocouple
Electromagnet
Commutator
Brushes
Armature
Electromagnetic induction
CONCEPT 1 – ENERGY
Learning Concept
Identify, describe and interpret examples of:
Mechanical energy
Chemical energy
Thermal energy
Electrical energy
Light energy
CONCEPT 1 – ENERGY
Electrical energy is the energy of chargedparticles
Transferred when electrons move from place toplace
Can be generated from various other types ofenergy
CONCEPT 1 – ENERGY
Mechanical energyis both the kineticenergy (Ek) and thepotential energy (Ep)in a system
CONCEPT 1 – ENERGY
Chemical energy isreleased from achemical reaction
Dry cells – electrolytechemicals are in a paste
Wet cells – uses a liquidelectrolyte
CONCEPT 1 –ENERGY
Thermal energy isthe total kineticenergy of all theparticles in asubstance
Most energy is lost asheat
CONCEPT 1 – ENERGY
A thermocouple is a temperature sensor at thejunction between two different metals
Produces a voltage proportional to the temperaturedifference between the hot and cold wires
CONCEPT 1 – ENERGY
Incandescent lightbulbs requireenough electricalenergy to make apiece of metal glowbrightly yet not getso hot it melts andbreaks
Resistance causes it toheat up and give off light
CONCEPT 1 – ENERGY
Learning Concept
Investigate and describe evidence of energytransfer and formation
CONCEPT 1 – ENERGY
You can use various devices to transformelectricity into other forms of energy
Examples of Devices that Convert Energy
Input Energy
Device
Output Energy
Electrical
Toaster
Thermal
Chemical
Flashlight
Electrical
Blender
Chemical
Battery-operatedclock
CONCEPT 1 - ENERGY
While a thermocouple convertsthermal energy into electricalenergy, other devices do theopposite
Ex. Heaters, ovens
The energy from the electrical charges istransferred to the atoms of the heatingelements
The heating elements warm up and heatthe oven
CONCEPT 1 - ENERGY
Learning Objective
Construct, use and evaluate devices fortransforming
Electrical energy into mechanical energy
Electromagnet & motors
Mechanical energy into electrical energy
Generators
CONCEPT 1 - ENERGY
Hans Christian Oerstedfound a compassneedle can beaffected if passed by acurrent-carrying wire
Indicated a relationshipbetween magnetismand electricity
CONCEPT 1 - ENERGY
Michael Faraday built adevice that usedelectromagnetic forces
Lead to thedevelopment of modernmotors
CONCEPT 1 - ENERGY
Electrical energy Mechanical energy
Most common devicefor this conversion is themotor
Use an electromagnet tocause mechanicalrotation, which can dowork
CONCEPT 1 - ENERGY
Faraday made asignificant electricaldiscover
Electromagneticinduction
Electrical current can begenerated by moving aconducting wire backand forth inside a coil ofwire
Mechanical energy Electrical energy
CONCEPT 1 - ENERGY
Science Log – Lab Challenge
Using the following materials only, build a magnet
Nail
Wire
Battery
Paper clips
Masking tape