Transcript File - Teacher Plant

Unit 2: Force, Motion, and Energy
Outline 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
DEPARTMENT OF EDUCATION
Electricity and Magnetism
Electric Field
Electrostatics
Electric Charge
Electric Force
Electric Potential
Electric circuit/connection
Electric
Current (I)
• Electrical Power
• Electrical energy
 Electric charges
 Attraction/Repulsion between charges
 Flow of charges (Simple electric circuit)
Gr. 8
Gr. 7
Magnetic
Field and
Current
Ohm’s Law
 Electric current (I, V, R relationship)
 Electrical connections (connections at home)
World of Electricity and Magnetism
Electric Field
Electrostatics
Electric Charge
Electric Force
Electric Potential
Electric circuit/connection
Electric
Current (I)
Ohm’s Law
• Electrical Power
• Electrical energy
Magnetic Field (B)
Magnetic
Field and
Current
Magnetism
• Magnetic Field
• Magnetic forces
B due to I
Electromagnets
Force of B on I
EM Induction
Faraday’s Law
Motors
•Generator/Transformer
•Power Transmission
Grade 9
Power Generation, Transmission, and
Distribution
Where does electricity
come from? How is it
produced? How does it
get to our home?
Source: http://www.netgainenergyadvisors.com/
Grade 10
What happens
inside the
generator? How
does it “produce
electricity”?
Electromagnetic
Induction
Source: http://upload.wikimedia.org/wikipedia/commons/4/42/Drax_power_station_generator.jpg
Grade 10
•Electric Motor
• Applications of EM
Waves (including Light)
How else is electrical
energy changed into
other forms of energy
that are useful to us?
Source: http://mamcomotors.com
G10 Force, Motion, and Energy
Electricty and Magnetism
Learning Competencies
Demonstrate the generation of electricity
by movement of a magnet through the
coil
Explain the operation of a simple electric
motor and generator
DEPARTMENT OF EDUCATION
G10 Force, Motion, and Energy
Electricty and Magnetism
Goals/Objectives
Understand the nature of magnet/magnetic field
o Magnetic domains
o
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.
DEPARTMENT OF EDUCATION
G10 Force, Motion, and Energy
Electricty and Magnetism
Goals/Objectives
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
DEPARTMENT OF EDUCATION
Getting hooked ...
The Floating Paper Clip
Learning Activities
Magnetism
Activity 1 For the Record…
Getting familiar with the various equipment
commonly found inside a radio broadcasting studio
Activity 2 Test Mag...1, 2!
Observing interactions between magnets and between
a magnet and ‘non-magnet’
Activity 3 Inducing Magnetism
Inducing magnetism in a magnetic material
Activity 4/5 Detecting Magnetism/Oh, Magnets…
Determining direction of magnetic field around a
permanent magnet using magnetic compass/magnetic
field creater
DEPARTMENT OF EDUCATION
Learning Activities
Electricity and Magnetism
Activity 6 Electric Field Simulation
Activity 7 Magnetic Field Simulation
Comparing electric and magnetic field lines using
PhET Interactive Simulations Project
DEPARTMENT OF EDUCATION
Learning Activities
Magnetism from Electricity
Activity 8
Activity 9
Magnetic Field around CurrentCarrying Conductors
Making your Own Electric Motor
Electricity from Magnetism
Activity 10 Let’s Jump In
Generating electricity with the aid of the Earth’s B
Activity 11
Principles of Electromagnetic Induction
Investigating factors affecting the strength and direction of B
Sample
Activity
Activity 8: Magnetic Field around
Current-Carrying Conductors
Objectives
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 Conductor
Materials needed
•
•
•
•
•
Straight currentcarrying conductor
setup*
Power supply/Dry cells
Connecting wires
Magnetic compass
Cardboard/Illustration
board
* Setup
conductor
supply
Source: http://www.ekshiksha.org.in/
Part B: Magnetic Field at the Center of a Coil
Materials needed
• Current-carrying coil setup*
• Power supply/Dry cells
• Connecting wires
• Magnetic compass
• Cardboard/Illustration board
* Setup
Source: http://www.ekshiksha.org.in/
Part A
Top View
out of the
paper
Magnetic
compass
into the
paper
Conductor
X
without current
with current
Part B
Side View
+
Clockwise
Counterclockwise
-
without current
+
with current
Activity Proper
The story behind...
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.
www.rare-earth-magnets.com
Hans Christian Oersted
(1777–1851)
Guide Questions
Part A
From a top-view perspective, in which direction
does the north pole of the compass needle point
when placed around the straight currentcarrying conductor? If the direction of the
current is reversed, in which direction does the
needle point?
Part B: Magnetic Field at the Center of a Coil
+
-
Visualizing Magnetic Field
http://www.ekshiksha.org.in//
Magnetic Compass
Iron Fillings
Direction of Magnetic Field
Right Hand Rule (RHR)
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)
Current
Magnetic
Field
http://www.ekshiksha.org.in//
Force on a current-carrying conductor in a
magnetic field
What happens when a
current -carrying
conductor is placed
within a magnetic
field?
http://www.ekshiksha.org.in//
EM Swing
Force on a current-carrying conductor in a
magnetic 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)
I
B
F
http://en.citizendium.org/wiki/File:Right-hand-rule.jpg
Application:
Working Principle of Electric Motor
http://tutorvista.com
Electric Motor
Concept Check
A current carrying wire is perpendicular to the
card as shown in the figure below.
Which of the arrows in the figure shows the
direction of the magnetic field at point Y ?
+
A
Y
B
D
C
DEPARTMENT OF EDUCATION
1.A
2.B
3.C
D
Concept Check
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
B
A
DEPARTMENT OF EDUCATION
1.A
2.B
3.C
D
Concept Check
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.
B.
C.
D.
to the right
to the left
vertically upwards
vertically downwards
DEPARTMENT OF EDUCATION
Concepts Learned
Magnetic Field
 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.
Concepts Learned
Motor Effect
 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.
Inquiry in Practice
Engaging in scientific-oriented questions
Gathering evidence
Providing explanations based on evidence
Communicating explanations
Process Skills
Observing
Inference
Predicting
Experimenting
Communicating explanations
Thank you 