Unit 2: Force, Motion, and Energy Force, Motion, and Energy

DEPARTMENT OF EDUCATION

Outline of PresentationOutline of Presentation

Progression of learning

G10 Electricity and Magnetism learning competencies

G10 Electricity and Magnetism goals and objectives

Learning activities

Sample activity

Discussion of results

Application of concepts derived from the activities

• Electrical Power• Electrical energy• Electrical Power• Electrical energy

Electric circuit/connection Electric circuit/connection Ohm’s Law

Electric ChargeElectric Charge Electric ForceElectric ForceElectric Field

Electric Potential

Electricity and MagnetismElectricity and Magnetism

Electric Current (I)Electric Current (I)

ElectrostaticsElectrostatics

Magnetic Field and Current

Magnetic Field and Current

Electric chargesAttraction/Repulsion between chargesFlow of charges (Simple electric

circuit)

Electric current (I, V, R relationship)

Electrical connections (connections at home)

Gr.

G

r.

77

Gr.

G

r.

88

• Electrical Power• Electrical energy• Electrical Power• Electrical energy

Electric circuit/connection Electric circuit/connection Ohm’s Law

Electric ChargeElectric Charge Electric ForceElectric ForceElectric Field

Electric Potential

Electric Current (I)Electric Current (I)

ElectrostaticsElectrostatics

Magnetic Field and Current

Magnetic Field and Current

EM InductionEM Induction

Magnetic Field (B)Magnetic Field (B)

Magnetism

B due to I

Force of B on I

Electromagnets Electromagnets

MotorsMotors

Faraday’s Law•Generator/Transformer•Power Transmission

•Generator/Transformer•Power Transmission

• Magnetic Field• Magnetic forces • Magnetic Field• Magnetic forces

World of Electricity and MagnetismWorld of Electricity and Magnetism

Grade 9Grade 9 Power Generation, Power Generation, Transmission, and Transmission, and

DistributionDistribution

Power Generation, Power Generation, Transmission, and Transmission, and

DistributionDistribution

Source: http://www.netgainenergyadvisors.com/

Where does electricity come from? How is it produced? How

does it get to our home?

Electromagnetic Electromagnetic InductionInduction

Source: http://upload.wikimedia.org/wikipedia/commons/4/42/Drax_power_station_generator.jpg

What happens inside the generator? How does it “produce

electricity”?

Grade 10Grade 10

•Electric MotorElectric Motor• Applications of Applications of EM Waves EM Waves (including Light)(including Light)

Source: http://mamcomotors.com

Grade 10Grade 10

How else is electrical energy

changed into other forms of

energy that are useful to us?

Demonstrate the generation of electricity by movement of a magnet through the coilExplain the operation of a simple electric motor and generator

DEPARTMENT OF EDUCATION

Learning CompetenciesLearning Competencies

G10G10 Force, Motion, and Energy Force, Motion, and Energy

Electricty and MagnetismElectricty and Magnetism

DEPARTMENT OF EDUCATION

Understand the nature of magnet/magnetic field

o Magnetic domainso Exploring magnetic field a. around permanent magnets of different shapes; b. between like and unlike poles; c. around a straight current-carrying conductor; d. around a current-carrying loop of wire; and e. around the Earth.

Goals/ObjectivesGoals/Objectives

G10G10 Force, Motion, and Energy Force, Motion, and Energy

Electricty and MagnetismElectricty and Magnetism

DEPARTMENT OF EDUCATION

Understand the relationship between electricity (electric current) and magnetism (magnetic field) and use this relationship in explaining principles behind generators, motors and other devices (recording devices)

o Investigate what happens when

• a current carrying conductor is placed within a magnetic field

• a conductor is moved within a magnetic field

Goals/ObjectivesGoals/Objectives

G10G10 Force, Motion, and Energy Force, Motion, and Energy

Electricty and MagnetismElectricty and Magnetism

Getting hooked ...Getting hooked ...

The Floating Paper ClipThe Floating Paper Clip

Activity 1Activity 1 For the Record…Getting familiar with the various equipment commonly

found inside a radio broadcasting studio

Activity 2Activity 2 Test Mag...1, 2! Observing interactions between magnets and between a

magnet and ‘non-magnet’

Activity 3Activity 3 Inducing MagnetismInducing magnetism in a magnetic material

Activity 4/5 Activity 4/5 Detecting Magnetism/Oh, Magnets…

Determining direction of magnetic field around a permanent magnet using magnetic compass/magnetic field createrDEPARTMENT OF EDUCATION

Learning ActivitiesLearning ActivitiesMagnetiMagnetismsm

Activity 6Activity 6 Electric Field Simulation

Activity 7Activity 7 Magnetic Field Simulation

Comparing electric and magnetic field lines using PhET Interactive Simulations Project

DEPARTMENT OF EDUCATION

Learning ActivitiesLearning Activities

Electricity and Electricity and MagnetismMagnetism

Learning ActivitiesLearning Activities

Activity 8 Magnetic Field around Current-Carrying Conductors

Activity 9Activity 9 Making your Own Electric Motor

Magnetism from Magnetism from ElectricityElectricity

Electricity from Electricity from MagnetismMagnetism

Activity 10Activity 10 Let’s Jump InGenerating electricity with the aid of the Earth’s B

Activity 11Activity 11 Principles of Electromagnetic InductionInvestigating factors affecting the strength and direction of B

Sample Sample ActivityActivity

Activity 8: Magnetic Field around Activity 8: Magnetic Field around Current-Carrying ConductorsCurrent-Carrying Conductors

ObjectivesObjectives

Using a compass, explore the magnetic field around current-carrying conductors.

Use the magnetic compass to determine the direction of a magnetic field

A. around a straight current-carrying conductor; and

B. at the center of the current-carrying coil.

Part A: Magnetic Field around a Straight ConductorPart A: Magnetic Field around a Straight Conductor

• Straight current-carrying conductor setup*

• Power supply/Dry cells

• Connecting wires

• Magnetic compass

• Cardboard/Illustration board

* SetSetupupconductor

supply

Source: http://www.ekshiksha.org.in/

Materials neededMaterials needed

Part B: Magnetic Field at the Center of a CoilPart B: Magnetic Field at the Center of a Coil

• Current-carrying coil setup*

• Power supply/Dry cells• Connecting wires• Magnetic compass• Cardboard/Illustration

board

Materials neededMaterials needed

* SetSetupup

Source: http://www.ekshiksha.org.in/

Part APart A

ConductorConductor

Magnetic Magnetic compasscompass

Top ViewTop ViewTop ViewTop View

without current

out of the paper

into the paper

with current

X

Part BPart B

Clockwise

Counterclockwise

without current

with current

+

-

+

-

Side ViewSide ViewSide ViewSide View

Activity ProperActivity Proper

In 1819, Hans Christian Oersted, a Danish physicist and chemist and a professor in the University of Copenhagen, discovered during a class demonstration that a current carrying wire would deflect the compass needle. He inferred that an electric current would induce a magnetic field.

Hans Christian Oersted (1777–1851)

The story behind...The story behind...

www.rare-earth-magnets.com

From a top-view perspective, in which direction does the north pole of the compass needle point when placed around the straight current-carrying conductor? If the direction of the current is reversed, in which direction does the needle point?

Part APart A

Guide QuestionsGuide Questions

Part B: Magnetic Field at the Center of a CoilPart B: Magnetic Field at the Center of a Coil

+

-

Magnetic Compass Iron Fillings

http://www.ekshiksha.org.in//

Visualizing Magnetic FieldVisualizing Magnetic Field

If a current carrying conductor is imagined to be held in the right hand such that the thumb points in the direction of the current, then the tips of the fingers encircling the conductor will give the direction of the magnetic lines (magnetic field)

Right Hand Rule (RHR)Right Hand Rule (RHR)

Current Magnetic Field

http://www.ekshiksha.org.in//

Direction of Magnetic FieldDirection of Magnetic Field

What happens when a What happens when a current -carrying current -carrying

conductor is placed conductor is placed within a magnetic field?within a magnetic field?

EM Swing

http://www.ekshiksha.org.in//

Force on a current-carrying conductor in a Force on a current-carrying conductor in a magnetic fieldmagnetic field

The direction of the force on a current carrying conductor in a magnetic field can be determined by using the right hand rule (RHR)

Force on a current-carrying conductor in a Force on a current-carrying conductor in a magnetic fieldmagnetic field

http://en.citizendium.org/wiki/File:Right-hand-rule.jpg

II

BB

FF

Application: Application:

Working Principle of Electric MotorWorking Principle of Electric Motor

Electric MotorElectric Motor

http://tutorvista.com

DEPARTMENT OF EDUCATION

A current carrying wire is perpendicular to the card as shown in the figure below.

Concept Check Concept Check

Which of the arrows in the figure shows the direction of the magnetic field at point Y ?

A

B

C

DYY

+

-

DEPARTMENT OF EDUCATION

A wire conductor is placed between the poles of a strong permanent U magnet as shown in the figure below. The direction of current I through the wire is also shown. Which arrow indicates the direction of the force on the wire?

I

1.A 2.B3.C

D

Concept Check Concept Check

AB

DEPARTMENT OF EDUCATION

1.A 2.B3.C

D

A rectangular loop of wire OPQR carrying a current is in a uniform magnetic field as shown in the figure below. What is the direction of the force on PQ?A. to the right

B. to the left

C. vertically upwards

D. vertically downwards

Concept Check Concept Check

An electric current produces magnetic effect around the conductor (called Magnetic Field)

The magnetic field surrounding a current-carrying conductor can be shown by sprinkling iron filings or arranging magnetic compasses around the conductor

The compasses line up with the magnetic field (a pattern of concentric circles about the wire) produced by the current.

When the current reverses direction, the compasses turn around, showing that the direction of the magnetic field changes also.

Magnetic FieldMagnetic Field

Concepts Learned Concepts Learned

A current-carrying conductor when placed in a magnetic field experiences a force.

If the direction of the field and that of the current are mutually perpendicular to each other, then the force acting on the conductor will be perpendicular to both. This is the basis of an electric motor.

The direction of the magnetic field, current and force can be determined using the RHR.

Concepts Learned Concepts Learned

Motor EffectMotor Effect

Engaging in scientific-oriented questions Gathering evidenceProviding explanations based on evidence

Communicating explanations

Inquiry in Inquiry in PracticePractice

Observing InferencePredicting

Experimenting

Communicating explanations

Process SkillsProcess Skills

Thank you Thank you