Download Downloand the Electromagnetism lesson

Electromagnetism
Author: Keri Randolph (modified from Zach McCoy and Amanda
Brown)
Grade Level: 8th grade science or Physical World Concepts
Note the blue boxes
throughout the plan
that note best practices
in STEM instruction.
Lesson Inspired by: FOSS Magnetism and Electricity; AIMS
Electrical Connections
Concepts:
Permanent magnets are objects with permanent magnetic fields
that give them forces of attraction and repulsion because they
contain a constant flow of electric charge. A magnetic field is
generated anytime an electrical current flows through a conductor.
Electromagnets are objects that produce a magnetic field only
when an electric current passes through them. Electromagnets
may be turned on or off, and made stronger by increasing the
number of turns of wire in the coil, increasing the current flowing
through the coil or by decreasing the radius of the coil. These
factors increase the current; therefore they increase the magnetic
force.
Recommended content source: Stop Faking It! Electricity &
Magnetism, NSTA Press.
The students will be able to:
● Explain that electric currents generate magnetic fields and a
coil of current-carrying wire behaves like a magnet.
● Comprehend that magnets are objects with a permanent
magnetic field and electromagnets are objects that exhibit
magnetic properties only when an electric current passes
through them.
● Design an investigation to test the variables that affect an
electromagnet’s strength.
● Analyze data to develop conclusions about the effect of each
variable on the strength of the electromagnet.
Key Questions
What is the relationship between electricity and magnetism?
How can we make an electromagnet more efficient?
Summarizing
concepts covered in
lesson helps ensure
that you have a good
grasp of the content.
Prerequisite Knowledge:
Students should have an understanding of simple circuits and how
to connect wires to batteries. This activity will review independent
and dependent variables.
Tennessee Curriculum Standards Addressed:
8th grade:
GLE 0807.Inq.1 Design and conduct open-ended scientific investigations.
GLE 0807.Inq.3 Synthesize information to determine cause and effect
relationships between evidence and explanations.
GLE 0807.Inq.4 Recognize possible sources of bias and error, alternative
explanations, and questions for further exploration.
GLE 0807.Inq.5 Communicate scientific understanding using
descriptions, explanations, and models.
GLE 0807.12.1 Investigate the relationship between magnetism and
electricity
GLE 0807.12.2 Design an investigation to change the strength of an
electromagnet
PWC:
CLE 3237.Inq.2 Design and conduct scientific investigations to explore
new phenomena, verify previous results, test how well a theory predicts,
and compare opposing theories.
CLE 3237.Inq.4 Apply qualitative and quantitative measures to
analyze data and draw conclusions that are free of bias.
CLE 3237.Inq.5 Compare experimental evidence and conclusions
with those drawn by others about the same testable question.
CLE 3237.Inq.6 Communicate and defend scientific findings.
CLE 3237.4.6 Investigate magnetic poles, magnetic fields, and
electromagnetic induction.
Common Core Connections:
Math Practices:
1. Make sense of problems and persevere in solving them.
3. Construct viable arguments and critique the reasoning of
others.
4. Model with mathematics.
5. Use appropriate tools strategically.
ELA Reading/Writing Standards for Literacy in Science and
Technical Subjects, grades 6-12
1. Determine the meaning of symbols, key terms, and other
domain-specific words and phrases as they are used in
specific scientific or technical context.
2. Integrate quantitative information expressed in words in a
text with a version of that information expressed visually.
3. Write arguments focused on discipline-specific content.
4. Write informative/explanatory texts, including the narration of
scientific procedures/ experiments.
NGSS Practices:
1. Asking questions (science) and defining problems
(engineering).
3. Planning and carrying out investigations.
4. Analyzing and interpreting data.
6. Constructing explanations (science) and designing solutions
(engineering).
7. Engaging in argument from evidence.
8. Obtaining, evaluating and communicating information.
Modification for Other Grades/Courses:
Physics- Students should be able to describe how current is
generated by electrical induction. (CLE 3231.5.6 & CLE 3231.5.7)
Materials List and Advanced Preparations: Per group: D cell
battery, wire with ends stripped, bolt, ruler, washers, cup, battery
holder (electrical tape can be used, but wires get hot!)
Per class: extra D cell batteries, wire stripper, nails, bolts of various
lengths and diameters, various gauges of wire, compass, magnet
Safety: The students will need to be aware that some parts of
the electromagnet (wiring) may become hot to the touch.
Best Practice:
The purpose of the engagement
is to “hook” students and assess
their prior knowledge. See
Elaboration section below for
another option.
Time:5 5 5 Minutes:
5
ENGAGEMENT
What the Teacher Will Do
We’re going to watch a short
video clip from Brave Little
Toaster.
Show cartoon video of
electromagnet:
http://www.youtube.com/watch?v
=-UfsEj7AOGI
Probing/Eliciting
Questions
Student Responses and
Misconceptions
Have you seen a magnet like
this? How does it work?
It can be turned off and on.
EXPLORATION I
What the Teacher Will Do
Probing/Eliciting
Questions
Complete a POE sheet following
teacher demonstrations or in
groups.
Students should predict, then
observe, then consider
explanations. This is best done in
small groups.
EXPLANATION I
What the Teacher Will Do
Have students summarize their
findings in a statement. (Groups
work great for this.)
Time: Minutes
Probing/Eliciting
Questions
What are your
conclusions?
What evidence do you
have?
How did your findings
differ from your
predictions?
Have students share the questions
they identified.
POE or Predict-ObserveTime: Minutes: 25
Explain sheets are a great
way and
to assess students’ prior
Student Responses
knowledge,
as well as
Misconceptions
identify naïve conceptions.
Student Responses and
Misconceptions
An electric current produces a
magnetic field.
The wire connected to the
battery moved the compass
needle.
Varies
This is a great stopping
place. I like to collect
and post the questions
generated by students
and return to them at the
end of the lesson/unit.
EXPLORATION II
What the Teacher Will Do
We’re now going to investigate
the relationship between
electricity and magnetism by
building an electromagnet.
I’m providing you with a D cell
battery, a piece of wire and a
bolt. See if you can make a
working electromagnet.
Be careful- the battery and wire
can become very hot. Why??
Time: Minutes: 25
Probing/Eliciting
Questions
Based on our findings in our
POE activity, how could we
turn this bolt into a magnet?
Student Responses and
Misconceptions
Connect it to a battery
How are electricity and
magnetism related? How
does this apply to our
situation?
Hold back one variable and
do not assign it to students.
It will be used for the
performance assessment at
the end of the lesson/unit.
Who has built a successful
magnetic device?
How do you know?”
(washers will be made
available)
How could we make our
electromagnets stronger?
we are picking up washers
Add batteries (voltage)
Use different gauge of wire
(thickness)
Lead students to the responses
on the right if needed... as
students introduce the potential
variables assign them to each
group. List these on the board or
a piece of chart paper.
After each group has been
assigned a variable, inform them
that they will need to assign a
group speaker to represent them
during the class discussion.
Wrap the wire looser/tighter
Spread number of wire
wraps out over bolt
Wrap the wire more times
around the bolt (Have more
wire touch the bolt/magnet)
Diameter of bolt
Pass out extra wire (gauge),
batteries, extra washers to the
appropriate groups
What data can we collect to
Number of washers/rivets
Lead students in development of study the effect of the variables picked up.
we’ve identified?
data table.
If you have time, leave
this out and allow
students to conduct
experiments, share data
and discover issues with
experimental design and
provide the opportunity to
repeat their experiments
after establishing
parameters. Ask- How
can we determine if one
of our variables affects
the strength of the
electromagnet more than
the others? This should
lead to a rich conversation
on experimental design
and involve students
writing a procedure.
How should we design our
Circulate around the room and
lead the groups to accomplish the experiments so that we can
compare our findings?
task and ask questions like:
EXPLANATION II
What the Teacher Will Do
Have students summarize their
findings on a poster and be
prepared to present.
Only change one variable at a
time. Decide on standard
basic procedure (number of
wire wraps, size of bolt, etc.)
Time: Minutes
Probing/Eliciting
Questions
What should we include
on our posters?
Student Responses and
Misconceptions
Variable
Data table
Conclusion
**Note: This can be used as an
opportunity for students to
discover issues with the
experimental design of the
class and lead to a discussion
of a common procedure.
The following questions are used
to help students make connections
Why did wrapping it
between the data collect and their
more times around the It concentrated the flow
experimentation with the concepts
bolt make it stronger?
of electricity and magnetism. This
can be done as a whole class
discussion or assigned to students
in groups to tackle.
Let’s analyze each of the variables
“Why did adding a battery it generated more electricitywe explored in groups and connect make it stronger?”
higher voltage
our findings to how electromagnets
work. See sample questions at right. “Is there a limit to how
many batteries may be
Yes, the wire can only carry
added?”
so much electricity
“Why did wrapping more It allowed the bolt to receive
wire around the bolt make more electricity
the magnet stronger?”
Using a guided discussion, help
students draw connections between
the variables and the concept of
electromagnetism. Make
connections between POE activity
and electromagnet experiment. One
way to accomplish this is to have
students explore some simulations on
electricity and magnetism. See list in
Elaboration.
With an electromagnet, a piece of Who has an idea how an the electricity moves and the
iron (it’s almost always used
electromagnet works
charges are not balanced
because of its permeability) is
now?
wrapped with a wire or a coil,
then electricity is passed through
the wire, which moves the
electrons (thanks electricity), and What are some benefits of Ability to change strength,
causes an imbalance in the
an electromagnet over a turn on/off
overall charge, creating a
magnet?
magnetic field.
ELABORATION- Option 1
What the Teacher Will Do
Provide scenario to class: Now
that we have investigated
electromagnets. There is a scrap
metal recycling company opening
in town. They are in the process
of designing their facility and are
accepting designs for the
electromagnet. We are going to
submit one or more designs by
developing a prototype
electromagnet. The company
wants to consider efficiency of the
electromagnet but also the cost
involved in making and operating
it.
Assign students design of
electromagnet. This works best if
costs are assigned to parts and
parameters for the pitch to the
company are set. This could be a
Probing/Eliciting
Questions
Why would a scrap metal
company be interested in an
efficient electromagnet?
This brings another
hallmark of problembased learning into the
Time: Minutes
lesson- a real world
scenario. This can be
Student Responses and
used to introduce the
Misconceptionslesson or it can be used in
Move large amounts of the Elaboration a shown
metal but need to be ablehere.
to Its placement is
best
decided based upon
turn magnet on and off.
students’ familiarity with
electromagnets, as well
as their experiences with
inquiry and PBL.
presentation, written assignment,
diagram, etc. Make sure students
are required to connect their
design to the essential questions or
content
ELABORATION- Option 2
What the Teacher Will Do
Have students explore the
applications of electromagnets and
conceptual connections between
electricity and magnetism. Using
sites such as:
http://www.howstuffworks.com/el
ectromagnet.htm
Probing/Eliciting
Questions
What are some products that
use electromagnets? Why
are electromagnets the best
choice for these products?
This second option for
Elaboration can be used in
conjunction with Option 1 or
Student Responsesinand
its place. It provides
Misconceptions experiences with simulations
and introduces more in-depth
content on magnetic fields,
etc. If you want to flip the
lesson, this could be used as
the content that students view
before beginning the lesson,
though this takes out much of
the inquiry. It could
http://www.fossweb.com/modules
3-6/MagnetismandElectricity/
http://phet.colorado.edu/en/simulat
ion/magnets-and-electromagnets
http://www.neok12.com/Electrom
agnetism.htm
http://dsc.discovery.com/tvshows/other-shows/videos/timewarp-electrifying-science.htm
EVALUATION
What the Teacher Will Do
Have students complete a
performance assessment on
electromagnets. Assign them
one variable not addressed in
the lesson (thinner wire is a
Time: Minutes
Probing/Eliciting
Questions
Student Responses and
Misconceptions
good choice). Either have
students perform the
experiment, collect data,
analyze results and develop a
conclusion connecting their
findings to the concepts of
electromagnetism OR present
students with the scenario and
have them write a hypothesis,
procedure, anticipated data,
etc.