A lesson I gave to middle school students during my time at Yale, with the Yale SPROUT student organisation.

1. Human
Knowledge
of the Physical World
By Jerrick Wee

3. Singapore

5. Human
Knowledge
of the Physical World
By Jerrick Wee

7. What is the shape
of the Earth?

8. Cube

9. Pyramid

10. Cylinder

11. Flat / Disc

13. How do we
know…?

14. How do we know that
the Earth is a sphere?

15. Lunar Eclipses

17. Lunar Eclipses

18. Lunar Eclipses

20. Lunar Eclipses

23. What is the size of
the Earth?

24. Circumference
Diameter Radius

26. Eratosthenes
(276BCE-194BC)

28. ?

29. S
800km
7°

30. 800km
7°

31. 800km
7°

32. 800km
7°
A circle has 360°.
7° of 360° is ~1/50.
If there are 800km in 7°,
how many km are there in 360°?
(in other words, what is the circumference of the Earth?)

33. 40000km
That’s the circumference of the Earth.
~24900 miles
Circumference = 800km x 50 = 40000km

34. ?
O
What about its radius?
(remember, C = 2πr)

35. 6400km
Diameter of the Earth:
800 x 50 = 40000km
2πr = 40000km
r = 6366km
O

36. 6400km
O

37. What is the mass
of the Earth?
(how heavy is the Earth?)

38. What is gravity?

40. F = ma
Newton’s Second Law of Motion

41. F = ma
Newton’s Second Law of Motion
Force mass acceleration

42. M1M2
F =
r2
G
Newton’s Law of Universal Gravitation

43. M1
M2
F2
F1
r

44. M1
M2
F2 F1
r

45. M1
M2
F2
F1
r

46. M1
M2
F2 F1
r

47. M1
M2
F2
F1
r

48. M1M2
F =
r2
G
Newton’s Law of Universal Gravitation

49. ME
a =
r2
G
Formula for the Mass of the Earth

50. ME
ar2
G
Formula for the Mass of the Earth
=

51. 6 000 000 000 000
000 000 000 000 kg
(13 200 000 000 000 000 000 000 000 lb.)

52. Density
The amount of stuff in a given space

53. m
p =
V
Formula for Density

54. m
p =
V
Formula for Density
mass
volume

56. 70% water
30% Sand (Silica)

57. 1000 kg m-3
1602 kg m-3

58. ? kg m-3

59. 70% water
30% Sand (Silica)

60. 70% water
30% Sand (Silica)
~1300 kg/m3 ?

61. m
p =
V
Formula for Density

62. 4
V = πr3
3
6400km
O

63. 6400km
O V = 1.1 x 1021 m3

64. 5500 kg m-3

65. What?

66. Journey to the
Centre of the Earth

67. Hell
(Dante’s Inferno)

68. Hypothesis #1 Hypothesis #2

70. Earthquake

71. Shadow zone
Seismic waves
Model #1 Model #2

72. We know that hypothesis #1 is correct.
Shadow zone
Seismic waves

74. Silicates (Sand)
Iron
The Early Earth
(when the Earth was first formed)
Uranium
Carbon

75. Where did all the
water come from?

76. Where did the
moon come from?

77. What was happening to
the Solar System then?

78. Liquid Iron Outer Core

82. Wee Jerrick
weejerrick@gmail.com
https://weejerrick.com