making laboratories count better integration of laboratories in physics courses by jim sizemore,...

Making Laboratories Count Better Integration of Laboratories in

Physics Coursesby

Jim Sizemore, Ph.D.Physics and Engineering Professor

Tyler Junior College, Tyler, TX

Greg Sherman, Ph.D.; Mike Broyles, Ed.D. Physics Professors

Collin College, Plano, TX

Acknowledgements:Meade Brooks, Ashok Kumar, Paul Johnson

Outline of Talk

• Issues– Students don’t take labs seriously– Poor math preparation

• Solution– Prelab packets– Quiz on prelab– Objective grading of labs

• Preliminary Results and Conclusions

Students don’t take labs seriously

• Informal survey of students– Admitted not preparing– Admitted expectation of good grade with only

modest effort

Poor Math Preparation• Course has Pre-Calculus Prerequisite• Gave Pre-Calculus Quiz at Start of Semester

• Surprised by inability to answer questions– Didn’t expect result, thus did not keep records

1) What is the equation of the line that includes the points (9.1,9.5) and (-7.8,-4.8) 2) Solve for x: -0.54x2 + 13.53x – 25.53 = 0 3) Refer to the following figure. What is sin(), cos(), tan(), , and h?

4) Solve for and calculate I: db=10log10ቀIIoቁ where db = 27 and Io = 10-12 W/cm2.

h 1.07

2.65

Prelab Packets

• Separated Lab into PreLab and Lab Components

• Students were required to turn in Prelab at beginning of lab

• Example on next slide

Example Prelab

Pre-Lab Quiz• Give Quiz at Beginning of Lab over Content of

Pre-Lab– Insures students do pre-lab preparation– Insures on-time attendance

• Quiz Asked Open Ended Questions. Examples:

– Grading Quizzes was Time Consuming– In Future Will Change to Multiple Choice Quizzes

1) The quantity mv is referred to as momentum and is conserved. In other words, when you add up the momentum of all the particles vector-wise before collision it equals the sum (vector-wise) of the momentums of all particles after collision. There is only one particle before collision with the pendulum – the steel ball. What is the expression for its momentum?

2) After it collides with the ballistic pendulum the two particles together have a momentum. What it the expression to the combined momentum of both after collision?

Objective Grading

• Labs Often Taught by Inexperienced Instructors

• Tendency to Judge Based on Scale of 1 to 10• Solution: Precise Point Assignment on 0 to

100 Scale– Example from Previous Slide

Example Prelab

SOLVE Method• 5 Steps

1) Sketch or Study2) Organize knowns and

unknowns3) Line up (equations)4) Vary (get working

equation)5) Evaluate

• Award 20% Credit for Each Step Completed

• Per Arnold Arons – systematic approach is important

Application of Bloom’s Taxonomy to Quantitative Fields

• Get Away From Memorizing Equations• Bloom’s Taxonomy Simplified

– Know– Understand– Apply– Synthesize– Critique

• Award 20% for each step of Bloom’s Taxonomy Completed

Other Grading Criteria• Tables and Graphs

– 20% for accurate tabulation or graphing– 10% for equations– and labeling axes, showing units, etc.

• Dimensional Analysis• Using Unit Fractions when Converting Units

• 3 Sig. Figs or Better• Etc. – at http://

www.funphysicist.net/physics_1401/labs/list.htm

Results• Some Evidence of Improvement Through

Semester• Overall Course Grade

A B C D F0

2

4

6

8

10

12

Grade (student estimate & actual)estimated actual

Results – Study Outside Class

• Evidence of Greater Effort

A B C D F0

1

2

3

4

5

6

7

Outside Study

A >3 hr, B ~3 hr, C ~2 hr, D ~1hr, F <1 hr

Results – Lab Grades

• Maybe Improvement Through Semester• However Inconclusive

1 2 3 4 5 6 7 8 9 10 11 12 130

20

40

60

80

100

120 Lab Grade (percent vs. week)

1 2 3 4 5 6 7 8 9 10 11 120

102030405060708090

100 Pre-Lab Grade (points vs. week)

1 2 3 4 5 6 7 8 9 10 11 120123456789

10 Lab Quiz Grade (points vs. week)

Conclusions

• Evidence of Better Student Engagement and Effort– Increased effort is appropriate– Underprepared students spend more time, however

succeed• Grades Improve• Doesn’t Require New Labs or Rewrites

– Develop grading scheme, break out pre-labs, develop multiple choice pre-lab quizzes

• Results Not Unequivocal, but are Encouraging

Future Work

• Gather Statistics Over Several Semesters to Understand Variability due to Differences Between Labs

• Retain Baseline Information of Beginning of Semester Quiz to Compare to Mid-Semester and End-of-Semester Data

• Establish Control Group for Comparison