1. a problem of scale

2. peter a’hearn

3. “i can see the molecules” -5 th grader peering into a test tube of water

4. “well you can’t because you’re old. I have really good eyes” -5 th grader when told he couldn’t possibly see molecules

5. “the test results shows the kids think the solar system and the universe are the same thing” “you mean they’re not?” -district level administrator

6. “there are positive and negative cells” -science teacher

7. “i am one cell” -high school biology student at the end of a unit on cells half the class agreed

8. “when i was a kid i didn’t believe in the solar system because when i looked in the sky i didn’t see anything that looked like the pictures in the books ” -elementary school teacher

9. “that is one atom of iron” -high school physical science Student looking at a beaker containing 55.85g of iron –one mole

10. just because they can give the right answer, doesn’t mean they get it

11. A Commonly Held Inaccurate Model of Teaching and Learning

13. as scales become bigger and smaller than those normally experienced, there is a tendency to lump objects into catergories of very big or very small -tretter, jones, and minogue 2006

14. experts and advanced students understand scale by unitizing- using new units when thinking in extreme scales- light years, nanometers, millions of years -tretter, jones, and minogue 2006

15. at your grade level, where do kids encounter extreme scales? big? small? in Space? in Time?

16. teaching kids about scale find out what they are thinking teach them to be critical of models put them in the picture help them figure it out for themselves use microscopes and telescopes

17. put the strips in order from the event that takes the shortest time to the event that takes the longest time

18. sun and earth 2

19. evaluate the model what is accurate about the model? what is inaccurate about the model?

20. Can you see a molecule with a magnifying glass?

21. 10 0 1 meter- you

22. 10 -1 1/10 meter

23. 10 -2 1/100 meter

24. 10 -3 1/1000 meter

25. 10 -4 1/10,000m cell

26. 10 -5 1/100,000 m

27. 10 -6 1/1,000,000 m organelles and bacteria

28. 10 -7 1/10,000,000 m- virus

29. 10 -8 1/100,000,000 m macromolecule

30. 10 -9 1/1,000,000,000 m molecule

31. 10 -10 1/10,000,000,000 m- atom

32. how big is the giant? who thinks you are a cell? who thinks you are a molecule?

33. 10 0 1 meter- you

34. 10 1 10 meters

35. 10 2 100 meters-soccer field

36. 10 3 1000 m- kilometer

37. 10 4 10,000 m –city the giant who thinks you are cell

38. 10 5 100,000 m

39. 10 6 1,000,000 m- state

40. 10 7 10,000,000 m-hemisphere

41. 10 8 100,000,000m

42. 10 9 1,000,000,000 meters Moon’s orbit The giant who thinks you’re an atom

43. at what scales do we teach kids about photosynthesis and respiration?

44. moon diameter 4000 km earth Diameter 13000 km earth to moon 400000 km step 1- change the units step 2- divide by 10s if that doesn’t nail it, try to divide or multiply by two.

45. try to add the sun! moon diameter 4000 km earth Diameter 13000 km earth to Moon 400000 km sun diameter 1400000 km sun distance 150000000 km

46. thank you peter a’hearn k-12 science specialist palm springs usd pahearn@psusd.us