1. SCIENCE 6 TOPIC 5

2. What does the word infer mean?

3. Infer means to suggest or make a hint based on facts. It is similar to a hypothesis.

4. Four inferred evidences that suggest that the earth’s shape is spherical

5. Sunshine will shine on hilltops first in the morning and last in the evenings.

6. Four inferred evidences that suggest that the earth’s shape is spherical Sunshine will shine on hilltops first in the morning and last in the evenings. Ships disappear gradually over the horizon with the mast seen last.

8. The shape of the earth’s shadow on the moon during an eclipse.

9. Four inferred evidences that suggest that the earth’s shape is spherical Sunshine will shine on hilltops first in the morning and last in the evenings. Ships disappear gradually over the horizon with the mast seen last. Eclipses produce a circular shadow.

10. Four inferred evidences that suggest that the earth’s shape is spherical Sunshine will shine on hilltops first in the morning and last in the evenings. Ships disappear gradually over the horizon with the mast seen last. Eclipses produce a circular shadow. North star “moves” from 90 to 0 degrees.

12. Two bits of evidence that point toward the earth not being an exact sphere

13. What?! The earth isn’t a perfect sphere? Well, it isn’t a square, either. Scientists believe the earth is “flat” on the poles and “gushed out” on the sides

14. Two bits of evidence that point toward the earth not being an exact sphere First, the force of gravity is not at the “true vertical” point at all points on the earth.

15. We’ll try to visualize this. If the earth were a perfect sphere…it would look like this: True Vertical Lines

16. But if the earth were “flat” at the poles and “gushed out” at the sides it would look like this… True Vertical Lines

17. But if the earth were “flat” at the poles and “gushed out” at the sides it would look like this… True Vertical Lines In fact, this is exactly what scientists find with earth.

18. Two bits of evidence that point toward the earth not being an exact sphere First, the force of gravity is not at the “true vertical” point at all points on the earth. Secondly, the force of gravity does not have the same strength at all points on the earth.

19. We’ll try to visualize this. If the earth were a perfect sphere…gravity’s force would be like this: 50 units of force

20. But if the earth were “flat” at the poles and “gushed out” at the sides it would look like this… 50 units of force 40 units of force

21. But if the earth were “flat” at the poles and “gushed out” at the sides it would look like this… 50 units of force 40 units of force Why the difference?

22. But if the earth were “flat” at the poles and “gushed out” at the sides it would look like this… 50 units of force 40 units of force Check out the length of the arrows

23. But if the earth were “flat” at the poles and “gushed out” at the sides it would look like this… 50 units of force 40 units of force There is more distance from the surface of the earth to the center of gravity’s force when one is at the equator. More distance means the force of gravity is not as strong.

24. The official name of the shape of the earth is an oblate spheroid

25. The three parts to the earth system

26. Lithosphere which is the rock portion of the earth

27. The three parts to the earth system Lithosphere which is the rock portion of the earth Hydrosphere which is any solid or liquid water on the lithosphere

28. The three parts to the earth system Lithosphere which is the rock portion of the earth Hydrosphere which is any solid or liquid water on the lithosphere Atmosphere which is made up of the gases which surround the earth

29. HOW DOES ONE FIND THE CIRCUMFERENCE OF THE EARTH ?

30. Finding the circumference of a sphere with help from Eratosthenes