Discovery Labs in Physics
Transformation of Intro Labs
• We have used an
NSF CCLI matching
grant to transform
intro physics labs
from “cookbook” to
“discovery” format.
Cookbook Labs
• The “cookbook”
lab manual directs
the student through
the lab. The student
is basically a
technician rather
than a scientist.
SHM - Cookbook
Lab Notebook. Keep notes for this experiment in your lab
notebook.
Data Acquisition. Use M in the range from 50 g to 500 g.
Include the mass of the mass holder in the value of M.
To get an accurate value of T measure the time for 20
periods.
(Note: begin the count at the end of the first period.)
Be sure that you estimate the uncertainties in both T and M.
SHM – Cookbook (2)
Data Analysis. Plot T2 (on the y-axis) vs. M (on the x-axis).
Find the slope of this line and the uncertainty in this value.
Find the y-intercept of this line and the uncertainty in this
value.
Write the experimental equation which relates T2 and M.
SHM – Cookbook (3)
Results.
Based on the linear fit values, what is the experimental
value of k and its uncertainty?
What is the physical meaning of the y-intercept, b?
Motivation for Change
• Brightest students considered the course to be boring.
• Course did not help develop conceptual
understanding.
• Course did not develop critical thinking.
Discovery
• The “discovery”
method involves
the student
actively in the
learning process.
The student does
science.
Discovery
•
•
•
•
•
Student-centered.
Develop conceptual understanding.
Develop critical thinking.
Encourage experimentation and imagination.
Encourage teamwork.
Discovery – Pre-Lab
The pre-lab
exercise
introduces
students to the
basic theory.
Physical Pendulum. The
period of a physical pendulum
for small angles is given by the
following equation:
Period = 2p (I/mgd)0.5
where m is the mass of the
pendulum, d is the distance
between the center of mass and
the center of rotation, and I is
the moment of inertia about the
center of rotation.
Discovery - Prediction
• Before making
measurements,
students are asked
to make
predictions
Consider a physical
pendulum made up of two
identical masses
connected to a low-mass
rod. The pendulum rotates
about the center of the
low-mass rod.
d2
center of rotation
d1
Discovery - Prediction
• These predictions
are recorded as
part of the
experiment
In your lab notebook,
describe how the period
will change as d2 is
increased. Assume d1 is at
its maximum value.
Explain why the period
changes in this way
d2
center of rotation
d1
Discovery - Measurement
• Measurements are
made to test the
predictions.
Set the lower mass near its lower end
(i.e. d1 equals 18 cm) and the upper
mass just below its upper end (i.e. d2
equals 17 cm).
Measure the period of oscillation for
small angles.
Repeat the period measurement for two
other positions of the upper mass.
Record the values of d1 & d2 and the
measured period in your lab
notebook.
Discovery - Analysis
• Students compare
predictions and
measurements to
test their
understanding of
the physical
phenomena.
In your lab notebook, compare
calculated and measured values
of the period of this physical
pendulum. Do the predicted
and measured values agree?
Conclusion - Pros
• More interesting.
• Students learn
concepts better.
• Students get more
hands on experience.
• Greater instructor
satisfaction.
Conclusion - Cons
• Less graphical
analysis.
• More work for
instructors.
• Appropriate hardware
and software is
required.