1. Ch 23 Section I The Earth

3. Earth is now known to be a round 3-dimensional sphere

4. Axis – imaginary vertical line around which earth spins

5. Rotation – the spinning of Earth around its axis that causes day and night

6. Earth has a magnetic field with north and south poles

8. Earth’s orbit is an ellipse. or elongated, closed curve

10. Earth’s tilt causes the seasons

11. The hemisphere tilted toward the Sun receives more daylight

12. The longer period of sunlight is one reason summer is warmer than winter.

13. Earth’s tilt causes the Sun’s radiation to strike the hemisphere at different angles

19. Moon Phases – the different forms the Moon takes in its appearance from Earth

20. New Moon – when the moon is between earth and the sun and cannot be seen

22. First visible thin slice of the moon is a waxing crescent

24. All of the Moon’s lighter side is visible during a full moon

25. Waning phases – less of the illuminated half of the Moon is visible after the full moon.

27. The last visible slice before a new moon is called the waning crescent

28. Eclipses – when the Earth or the moon casts a shadow on the other

30. A total solar eclipse is visible only on a small area of Earth

32. Lunar Eclipse – when Earth’s shadow falls on the moon

34. The Moon’s surface has many depressions, or craters. formed from meteorites, asteroids, and comets

36. Cracks in the Moon’s crust caused lava to fill large craters, forming maria, or dark, flat areas

37. Data from moonquakes suggest that under the Moon’s crust might lie a solid mantle, then a partly molten mantle and a solid, iron rich, core.