Download 1 Slinking round Learning Objectives: 1. Explore the Earthss

Slinking Around
Learning Objectives:
1. Explore the Earth’s magnetic field in your room.
2. Determine the relationship between magnetic field and the length of a coil.
3. Use a Magnetic Field Sensor to measure the field at the center of a coil.
4. Determine the relationship between magnetic field and the number of turns in a
coil.
5. Determine the relationship between magnetic field and the current in a coil.
6. To acquire familiarity with basic magnetic phenomena
7. To use technology to gather, analyze, and communicate mathematical
information
8. Select and use appropriate instrumentation to design and conduct investigations
9. Represent ideas using various forms of representations, such as graphs, data
tables, sketches, and equations.
10. When performing mathematical operations with measured quantities, express
answers to reflect the degree of precision and accuracy of the input data.
Purpose: The purpose of this laboratory is to investigate the factors that affect the
magnetic field (B) inside a coil (slinky).
Materials:
Bar magnet
D-cell battery
alligator clip lead
Slinky
LoggerPro interface (LabPro, mini Lab Quest, or LabQuest2)
Vernier Constant Current Source (CCS-BTA, $59) or power supply or D-cell batteries
Vernier Magnetic Field Sensor (MG-BTA, $58)
10 Ω resistor
I.
Exploration: Exploring magnetic fields
1. Measuring magnetic fields of bar magnets.
What does the magnetic field look like around a bar magnet?
Zero the magnetic field sensor. Use the
Magnetic Field sensor hooked to a LoggerPro interface and
measure the magnetic field around a bar magnetic.
Sketch the magnetic field.
2. Measuring magnetic field of a coil of wire attached to a D-cell battery.
Using a wire with alligator leads on both end, wrap the insulated wire into a loop.
You may want to tape the loop. Zero the magnetic field sensor again. Move the
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magnetic field sensor through the loop from both directions. What do you notice
about the magnetic field around a loop of wire?
Now attach the alligator clips to the end of a D-cell battery. Measure the magnetic
field through the loop. How does the magnetic field compare to the loop not
attached to a battery?
Compare the magnetic field through the loop by moving the magnetic field sensor
into the loop from both sides of the loop. Explain your observations.
Checkpoint 1! Explain magnetic fields of bar magnets and a loop of wire
connected to a battery.
II. Exploration: Exploring magnetic fields in a slinky
You are likely familiar with a metal slinky, having played with them as
a child by setting them in motion down stairs. But slinkies can be
used as a model of a solenoid which you investigated in the prelab
activity.
What happens when a current runs through a slinky?
1. Set up equipment. Stretch a slinky
across a lab table. Using alligator clip
leads, connect the slinky in series with a
10Ω resistor and a current source
(battery, power supply or constant
current source).
2. Measure Magnetic Field. Using a
LoggerPro interface (LabPro, mini LQ,
or LQ2), measure the magnetic field
around the slinky. How should the
magnetic field sensor be positioned to
measure the magnetic field in a slinky?
How does the magnetic field measurements differ if you
measure through one end of the slinky compared to the other
end of the slinky? Why?
What do you think the magnetic field looks like around the
slinky hooked to a current source? Sketch below.
Actual set up
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III.
Design an Experiment
Research Question: What affects the magnetic field in a slinky?
1. List factors that could affect the magnetic field in a slinky
Some ideas students might suggest are:
- the number of turns in a slinky (coil)
- the length of the slinky
- the electric current intensity
- the diameter of the slinky
- the material the slinky is made of
2. Design your experiments by filing in the table below.
Experiment 1
Hypothesis
Current affects the
magnetic field
Prediction
As current increases,
magnetic field
increases
Independent Current
Variable (IV)
Dependent
Magnetic field
Variable
(DV)
Control
Length (L), number
Variable
of turns (N)
(CV)
Experiment 2
Length of solenoid affects
magnetic field
As length increases,
magnetic field decreases
Length of solenoid
Experiment 3
Number of turns
affects magnetic field
As number of turns
increase, magnetic
field increases
Number of turns (N)
Magnetic field
Magnetic field
Current (I), number of
turns (N)
Current (I), length of
solenoid (L)
Use either group whiteboard meeting or instructor checkpoints
****Whiteboard Activity ***
Put your factors on a whiteboard to discuss in a board meeting.
Checkpoint 2! Discuss your design with your lab instructor before continuing.
3. Conduct an experiment to test each of the factors. (Different lab groups could
test different factors and present in the lab.)
4. Graph data. What relationships did you find between the various factors?
Checkpoint 3! Make a claim based on evidence and explain your rationale.
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