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. 2 Outline Goals of Science Education Research Questions Survey Design and Analysis Results Discussion

3. Goals of Science Education

4. 4 General Goals The University of Maine�s General Science Education Requirement Laboratory-based science (1 to 2 semesters) Broad learning goals: Read/understand articles (e.g. in �Science�1) Apply scientific principles correctly.1 Large variation among departments.

5. 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. 7 Question 1 Do general education students in introductory level science courses learn Conservation of Energy and Mass?

8. 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. 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. 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; doesn�t stay in the system C: limited; unlimited D: conserved; isn�t conserved E: recycled; lost

12. 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. 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. 14 Survey Implementation Courses Biology: BIO100 Chemistry: CHY121 Earth Science: ERS101 Physics: PHY105 Administration non-graded pre-test non-graded post-test.

15. 15 Survey Analysis Matched data (started with ~850 students) Score attained from 10 application questions 5 �local� 5 �systems� Primary analysis: average normalized gain <g> <g>=(post-test - pre-test)/(100 - pre-test) Sub-groups are mostly students taking only one science course in the Fall term.

16. Results

17. 17 Overall

18. 18 �Local� Conservation

19. 19 �Systems� Conservation

20. Discussion

21. 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. 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. 23 The Positives

24. 24 The Negatives

25. 25 Limitations Course choices Question analysis Interviews for validity Item analysis Item/course analysis

26. 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. 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.

28. 28 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.

29. 29 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.

30. 30 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 isn�t enough information to determine an answer.

31. 31 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.

32. 32 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 isn�t/wasn�t relevant to this class specifically. A: strongly disagree B: disagree C: neither disagree nor agree D: agree E: strongly agree