Student Understanding of Conservation of Energy and Mass in Introductory University Science Courses

1
Student Understanding of Conservation of Energy
and Mass in Introductory University Science
Courses

• Jessica Odell, M.S.T. Candidate
• University of Maine
• August, 2005

2
Outline

• Goals of Science Education
• Research Questions
• Survey Design and Analysis
• Results
• Discussion

3
Goals of Science Education
4
General Goals

• The University of Maines General Science
  Education Requirement
• Laboratory-based science (1 to 2 semesters)
• Broad learning goals
• Read/understand articles (e.g. in Science1)
• Apply scientific principles correctly.1
• Large variation among departments.

1 Reports from General Education Assessment
Working Groups Fall 2003. (2003). Orono, Maine
University of Maine.
5
Content Goals An Example

• Conservation of Energy and Mass
• Often in Thermodynamics
• Mathematical (balancing equations)
• Misconceptions
• Persistent throughout instruction
• Often found in textbooks
• Often found among teachers

6
Research Questions
7
Question 1

• Do general education students in introductory
  level science courses learn Conservation of
  Energy and Mass?

8
Question 2

• Are there differences in student understanding of
  Conservation of Energy and Mass between
  introductory science courses that fulfill the
  gen ed requirement?

9
Survey Design and Analysis
10
Survey Design

• Preliminary Free-Response Survey
• Final Multiple Choice Survey
• Book Keeping Questions
• Basic Concepts
• Specific applications of conservation of energy
  and mass
• Local applications (mostly mass)
• System applications (mostly energy)
• Attitudes

11
Basic Concepts

• Energy can best be described as?
• A a force needed to do work
• B heat
• C work done on an object
• D an ability to do work
• E an interaction between molecules
• In closed systems energy is __________, and in
  open systems energy is ___________.
• A stored to be used at a later time cannot be
  stored for later use
• B stays in the system doesnt stay in the
  system
• C limited unlimited
• D conserved isnt conserved
• E recycled lost

12
Local Conservation

• What is the mass of the solution when 1 kilogram
  of salt is dissolved in 20 kilograms of water?
• A 19 kilograms.
• B 20 kilograms.
• C Between 20 and 21 kilograms.
• D 21 kilograms.
• E More than 21 kilograms.
• Which of the following must be the same before
  and after a chemical reaction?
• A The sum of the masses of all substances
  involved.
• B The number of molecules of all substances
  involved.
• C The number of atoms of each type involved.
• D Both (a) and (c) must be the same.
• E Each of the answers (a), (b), and (c) must
  be the same.

13
Systems Conservation

• The initial phase of an avalanche can be used as
  an example of conservation of energy because it
  represents
• A change in kinetic energy to potential energy
• B change in thermal energy to mechanical
  energy
• C change in potential energy to kinetic energy
• D change in thermal energy to gravitational
  energy
• E change in gravitational energy to kinetic
  energy

14
Survey Implementation

• Courses
• Biology BIO100
• Chemistry CHY121
• Earth Science ERS101
• Physics PHY105
• Administration
• non-graded pre-test
• non-graded post-test.

15
Survey Analysis

• Matched data (started with 850 students)
• Score attained from 10 application questions
• 5 local
• 5 systems
• Primary analysis average normalized gain ltggt
• ltggt(post-test - pre-test)/(100 - pre-test)
• Sub-groups are mostly students taking only one
  science course in the Fall term.

16
Results
17
Overall
ltggt (post - pre) (100 - pre)
18
Local Conservation
ltggt (post - pre) (100 - pre)
19
Systems Conservation
ltggt (post - pre) (100 - pre)
20
Discussion
21
Question 1 Content

• Do general education students in introductory
  level science courses learn Conservation of
  Energy and Mass?
• Significant gains are seen,yet final percentages
  are cause for concern.
• Overall final percentages are still around 50

22
Question 2 Differences

• Are there differences in student understanding of
  Conservation of Energy and Mass between
  introductory science courses that fulfill the
  general science education requirement?
• Yes.

23
The Positives
Biology overall ltggt 0.11 local ltggt
(o.01) systems ltggt 0.18
Chemistry overall ltggt 0.00 local ltggt
(0.30) systems ltggt (-0.22)
Biology/Chemistry overall ltggt 0.22 local ltggt
0.18 systems ltggt 0.25
24
The Negatives
25
Limitations

• Course choices
• Question analysis
• Interviews for validity
• Item analysis
• Item/course analysis

26
Recommendations

• Study the other science courses that fulfill the
  general education requirement.
• CHY101
• PHY111
• Continue reform so that all students at The
  University of Maine can meet both goals of the
  general science education requirement.

27
Many Thanks To

• Thesis advisor Dr. Michael Wittmann
• Thesis committee
• Dr. Francois Amar
• Dr. Stephen Norton
• Dr. Mary Tyler
• Fellow M.S.T. students and office-mates.
• Innocence about Science is the worst crime today.
• -Sir Charles Percy Snow (1905-80) English
  novelist and scientist.

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The Rest of the Survey

• 9. True or False? When a match burns, some mass
  is destroyed.
• A True B False
• 10. What is the reason for your answer to
  question 9?
• A This chemical reaction destroys mass.
• B Mass is consumed by the flame.
• C The mass of ash is less than the match it
  came from.
• D The atoms are not destroyed, they are only
  rearranged.
• E The match weighs less after burning.

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The Rest of the Survey

• 12. Biological systems are often considered open
  systems, so energy conservation does not apply.
• A True B False
• 13. What is the reason for your answer to
  question 12?
• A energy in open systems is lost.
• B energy in open systems is unlimited.
• C energy in open systems is exchanged with the
  outside.
• D energy in open systems is transferred to
  other things.
• E energy in open systems is converted into
  matter.

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The Rest of the Survey

• 14. Two billiard balls of equal masses are on a
  level, frictionless surface. The first ball is
  moving and collides with the second ball, which
  was stationary. After the collision, both balls
  are moving. What is the speed of the first ball
  after the collision?
• A less than its original speed.
• B the same as its original speed.
• C more than its original speed.
• D there isnt enough information to determine
  an answer.

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The Rest of the Survey

• 15. The Water Cycle is an example of
• A an open system. B a closed system.
• 16. What is the reason for your answer to
  question 15?
• A conservation of water.
• B conservation of energy.
• C conservation of mass.
• D conservation of luck (I guessed).
• E conservation of natural resources.

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The Rest of the Survey

• 18. The law of conservation of energy
  applies/applied to the course I am taking.
• 19. The law of conservation of energy will
  be/was taught in detail in the course I am
  taking.
• 20. The law of conservation of energy is
  relevant to the field of science this course is
  about, but isnt/wasnt relevant to this class
  specifically.
• A strongly disagree
• B disagree
• C neither disagree nor agree
• D agree
• E strongly agree