Solar Cooker Data

1. Solar Cooker Data Time Plain Insulated (oC) (oC) 0 23 22 2 29 30 4 32 36 6 33 40 8 34 43 10 35 45 12 35 46 14 35 47 16 35 47 Time Plain Insulated (oC) (oC) 18 35 47 20 35 47 22 35 47 24 35 47 26 35 47

2. Energy Resources

3. Energy is the capacity to do work. Energy is measured in Joules 1 Joule of energy can raise 1 N of weight exactly 1 meter 1 J=1N•m (PS: your diet offers ~5-10 million J/day)

4. First Law of Thermodynamics Energy can neither be created nor destroyed. It can be converted to another form.

5. Energy is the capacity to do work. Forms include:

6. Energy is the capacity to do work. Forms include: • Kinetic energy • Potential energy • Chemical energy • Heat • Elastic potential energy • Electrical energy

7. Energy is the capacity to do work. Together, these are called “mechanical energy” Forms include: • Kinetic energy • Potential energy • Chemical energy • Heat • Elastic potential energy • Electrical energy Friction converts kinetic energy to heat

8. Conversion of energy

9. Conversion of energy Electrical energy lifts cars

10. Conversion of energy Highest potential energy

11. Conversion of energy Highest kinetic energy

12. Conversion of energy potential kinetic

13. Conversion of energy kinetic  potential

14. Heat: Rule 1 • All matter is composed of particles in constant motion

15. Heat: Rule 2 • Temperature is a measure of the kinetic energy of the particles.

16. Heat: Rule 2 (a and b) • Temperature is a measure of the kinetic energy of the particles. a) When you heat a sample, the particles speed up b) When you cool a sample the particles slow down

17. Heat: Rule 2 (a and b) • Temperature is a measure of the kinetic energy of the particles. a) When you heat a sample, the particles speed up b) When you cool a sample the particles slow down Absolute zero is the temperature at which the particles stop (-273oC)

18. Particles in motion: • Solid Liquid Gas

19. Heat transfer • Hot things cool and cold things warm up. • Duh.

20. Heat transfer • Hot things cool and cold things warm up. Three ways:

21. Heat transfer • Hot things cool and cold things warm up. Three ways: • Convection • Conduction • Radiation

22. Convection Heat is carried up by the hotter mantle material which is less dense.

23. Conduction Objects in contact Cold Hot

24. Conduction Not so cold Not so hot Cold Hot

25. Conduction Not so cold Not so hot Cold Hot Hot (fast) particles collide with cool (slow) particles. The fast ones slow down while the slow ones speed up

26. Conduction Not so cold Not so hot Cold Hot Fast (hot) particles collide with slow (cool) particles. The hot ones cool down while the cool ones warm up

27. Radiation

28. Radiation • Heat is transferred by electromagnetic radiation—visible and not-so-visible light.

29. The electromagnetic spectrum Hot objects glow in visible light Warm objects “glow” in infrared light

30. Review—How can this hot object lose heat?

31. Review—How can this hot object lose heat?

32. Energy, Work, and Power • Energy . • Work . • Power

33. Energy, Work, and Power • Energy—the capacity to do work • Work—exerting a force over a distance • Power—the rate of work being done

34. Energy, Work, and Power • Energy—the capacity to do work • Work—exerting a force over a distance • Power—the rate of work being done Work = Force x distance

35. Energy, Work, and Power • Energy—the capacity to do work • Work—exerting a force over a distance • Power—the rate of work being done Energy = the amount of work done Work = Force x distance

36. Energy, Work, and Power • Energy—the capacity to do work • Work—exerting a force over a distance • Power—the rate of work being done Energy = the amount of work done Work = Force x distance Power = work / time

37. Energy, Work, and Power • Energy—the capacity to do work • Work—exerting a force over a distance • Power—the rate of work being done Measured in Joules Measured in Joules Measured in Watts

38. Energy, Work, and Power • Energy—the capacity to do work • Work—exerting a force over a distance • Power—the rate of work being done Measured in J, kJ, cal, kcal, ft-lb, BTU, Q, kWh Measured in J, kJ, cal, kcal, ft-lb, BTU, Q, kWh Measured in W, hp, ft-lb/s

39. U&A Question 5 • 300 hp=300 x (550 ft-lb/s) =165000 ft-lb/s! • This motor could lift 165000 lbs at a rate of 1 ft/s (or) • 16500 lbs (a freight elevator) at 100 ft/s

40. How do you get energy to do work?

41. To generate electricity… How would you like to heat your water?

42. Second Law of Thermodynamics When energy converted to another form, some of the energy is lost as unusable heat.

43. Second Law of Thermodynamics When energy converted to another form, some of the energy is lost as unusable heat. (or) Energy conversion is never 100% efficient.

44. Electricity • A generator generates electricity. • Work done on the generator is converted to electrical energy • You do work on the generator by turning the crank.

45. What turns your crank? • A turbine converts kinetic energy of a fluid into rotation. • Most electricity is made by steam driving a turbine

46. To generate electricity… How would you like to heat your water?

47. Options for turning a turbine Heatsteam

48. Options for turning a turbine Heatsteam • Coal • Natural gas • Nuclear fission • Biomass • Solar • Ocean thermal

49. Options for turning a turbine Heatsteam Direct • Coal 1) • Natural gas 2) • Nuclear fission 3) • Biomass • Solar • Ocean thermal

50. Options for turning a turbine Heatsteam Direct • Coal 1) Hydroelectric • Natural gas 2) Wind • Nuclear fission 3) Tidal • Biomass • Solar • Ocean thermal