Student Misconceptions about Science

1. Student Misconceptionsabout Science RFUMS Master Teachers’ Guild John Becker, Ph.D.

2. Learning Objectives Participants will: • Learn how to identify misconceptions that students hold • Identify the likely sources of the misconceptions • Learn what remedies can correct misconceptions

3. Misconceptions about Learning From Faculty Focus, January 29, 2014: • Learning is fast • Knowledge is composed of isolated facts • Being good at a subject is a matter of inborn talent rather than hard work • I’m really good at multi-tasking, especially during class or studying.

4. SCIENCE MISCONCEPTIONS • Flawed mental models, not just missing facts. • Sun revolves around the earth? • One definition (Michael, 1998): • An incorrect model for a phenomenon regardless of its possible origin. • Published examples from: physics, chemistry, neuroscience, psychology, biochemistry, exercise science, heart failure, etc.

5. Some hot (and cold) misconceptions from physics • Everything contracts in the cold • Fill a water glass and put it in your freezer • Everything expands in the heat • Plate-with-a-hole problem

6. Plate-with-a-hole problem • Put a metal plate with a hole in the center into an oven and heat it. • What happens to the hole? • Take 1-2 minutes by yourself C B A

7. You are not alone • Eric Mazur thoroughly covered heat in Harvard’s freshman Physics lecture course. • But, many students got it wrong, as did Harvard professors, as did physiologists at a meeting.

8. Group Activity Discuss among yourselves for 3-4 minutes • And, imagine metal molecules as people standing in a circle, who want to get as far away from neighbors as possible.

9. Group Activity, cont. C

10. How to find misconceptions • Multiple choice exams (over several years) • PrepU exam bank has “misconception alerts” • Formative pre-tests (Lazarowitz, 2005) • Office visits/tutor sessions • Ask for reasons during lecture (Socratic) • Direct interlocution or indirect with clickers • Educational literature in your profession

11. Sources of misconceptions • Learned in other courses (K-16) • Grounded: not from other education • Intuitive ideas from everyday life • Even observing their own body does not help dissuade them • Teleology: “the body needs to…”

12. Sources that we can control • Sometimes it is language: • Absorption ≠ Reabsorption ≠ Resorption • Two renal thresholds (Cheng, 2012) • Missing adjective: arterial blood pressure • “Elastic” in physics vs everyday language • “positive feedback” in physiology vs pop psychology • Sometimes it is poor analogies • Arterial vs venous compliance • In the future, Virtual Reality programs may apply reductionism to complex biological problems (Richardson, 2011)

13. Compliance • From physiology textbooks: venous compliance is 20X that of arterial compliance. • Compliance = Δvolume/Δ pressure • (how easy it is to fill an elastic container) • Dr. Becker’s bad 2-D analogy: thin and thick rubber bands • But venous grafts to replace blocked coronary arteries must be tough. • A better 2-D analogy: area within a circle vs. area within an ellipse.

14. Shapes • The “fabric” of arteries and veins are similar, but circles have bigger areas than ellipses of the same circumferences • And in 3-D, cylindrical cans hold more volume than oval cans • Compliance = Δvolume/Δ pressure • (how easy it is to fill an elastic container) Normal vein Vein when blood is stored in an organ (e.g., depend your hand)

15. Sometimes it is figures or charts • The terminology of the basic physiological concept of “homeostasis” is not used consistently across textbooks (and sometimes within one textbook), especially in figures (Michael, 2013) • e.g. see-saw in a feedback loop drawing may lead students to misconceive that homeostasis only operates when there is an imbalance

16. Homeostasis Drawing • Does the system shut down when there is balance? • Where is the “set point”? • “Negative feedback” is not explicit Control Center Receptor/Sensor Effector Variable in homeostasis Imbalance Imbalance Based on Michael 2013

17. Sometimes it is graphs • Some textbooks use graphs from experiments, but students may think the graph explains an observation of an unprovoked situation.

18. Stroke Volume in Experiments & Exercise Silverthorn

19. Physiological Examples • Cardiac Output = Heart Rate X Stroke Volume • H.R. goes up in exercise, but what about stroke volume? • Many students think it goes down or stays the same • Analysis from research (Michael, 1998): “Cardiac output must be kept constant” • Does this come from emphasis on feedback loops? • But the variable held constant is blood pressure, not cardiac output. • Does this come from the previous figure? • Others: right & left cardiac output; pulse vs blood velocities; resistances in parallel (Palizvan, 2013)

20. Respiratory • Minute Ventilation = Resp. Rate X Tidal Volume • R.R. goes up in exercise, but what about VT? • Similar misconception: VT either stays the same or drops to keep ventilation per minute constant • Or, not enough time to fill the lungs at high rates • In this case, students ignore what they can observe after running up the stairs (deeper & faster breathing)

21. What to do? • Re-lecturing does not work: • Misconceptions persist across tests and across courses (Michael, 1998; Silverthorn, 2002) • Eric Mazur abandoned lecturing

22. Remedies • Sometimes labs or demonstrations can help, esp. if students are asked to predict • Sometimes making students aware that this concept is often misconceived: • Teach to misconceptions “targeted instruction” (Christensen, 2008) • Let your tutors know, too • Explain the components & limitations of analogies (Broom 2010) • “Interventions” (Leinonen, 2013) • Hints & Peer Interaction (e.g. discussion among peers about the hole problem) • Other Active Teaching methods • Caveat: some students don’t want active methods

23. Informal Survey at RFUMS Dr. Oblinger: Hair & fingernails grow after death. • The skin dries and shrinks away from the bases of hairs and nails, giving the appearance of growth.

24. DISCUSSION • Share your pet misconception. • Ideas about remedies? • Does it matter?