1. Key Concepts What are solar and lunar eclipses? What causes the tides?
Seasons, eclipses, and tides
Key Concepts
What are solar and lunar eclipses?
What causes the tides?

2. WHY DO WE HAVE SEASONS?
Seasons are the result of the tilt of the Earth's axis.
Earth’s axis is tilted 23.5°.
This tilting is why we have SEASONS like fall, winter, spring, summer.
The number of daylight hours is greater for the hemisphere, or half of Earth, that is tilted toward the Sun.

3. SOLSTICES
Solstices occur twice a year, when the tilt of the Earth's axis is oriented directly towards or away from the Sun, causing the Sun to appear to reach its northernmost and southernmost extremes.
Winter solstice is the shortest day of the year. In the Northern Hemisphere. It occurs on December 21 and marks the beginning of winter.
The Summer Solstice is the longest day of the year. It occurs on June 21 and marks the beginning of summer.

4. SOLSTICE
During the winter the Northern Hemisphere day lasts fewer than 12 hours and the Southern Hemisphere day lasts more than 12 hours.
During the winter solstice, the North Pole has a 24-hour night and the South Pole has a 24-hour day.
Sunlight strikes the earth most directly at the Tropic of Capricorn.

5. EQUINOXES
A day lasts 12 hours and a night lasts 12 hours at all latitudes.
Equinox literally means "equal night".
Sunlight strikes the earth most directly at the equator.
This occurs twice a year.

6. EQUINOX The vernal (spring) equinox occurs March 21.
The autumnal (fall) equinox occurs September 21.

7. Eclipses Occurs when: moon’s shadow hits Earth or
Earth’s shadow hits moon
When an object in space comes between the sun and a third object it casts shadow on that object = eclipse

8. When do solar eclipses occur?
New moon – moon is between sun and Earth
Most months the moon is a little above or below sun in the sky.
Solar eclipse occurs when the moon passes directly between the Earth and sun, blocking light from the sun

9. Partial Solar Eclipse
Not safe to look at the sun during a partial eclipse because an extremely bright part of the sun remains visible

10. When do Lunar Eclipses Occur?
During the full moon when the Earth is directly between the sun and moon
Moon is in Earth’s shadow

11. Total Lunar Eclipses Earth’s shadow has an umbra and penumbra
When moon is in Earth’s umbra – you see a total lunar eclipse
Can see total lunar eclipse from anywhere on Earth

12. Partial Lunar Eclipse
Most lunar eclipses, Earth, the moon and the sun are not quite in line = partial lunar eclipse
Brainpop: Eclipses
Youtube: Eclipse

13. Tides Rise and fall of ocean water that occurs every 12.5 hours
Water rises for 6 hours and then falls for 6 hours
Caused by differences in how much the moon’s gravity pulls on different parts of Earth
Bay of Fundy Tides Video

14. The Tide Cycle
High tides occur on the side of the Earth closest to the moon due to the moon’s gravity pulling on the water
High tides also occur on the side of the Earth farthest from the moon. The moon’s gravity pulls on the Earth more strongly than it pulls on the water leaving it behind
In between the two high tides, low tides occur
Study Jams video

15. STOP
Pick up from here after moon phases

16. The Tide Cycle

17. Spring Tides Sun’s gravity pulls on Earth’s waters
During a new moon – sun, moon and Earth are nearly in a line.
Gravity of sun and moon pull in same direction
Combination of forces produce tide with greatest difference between low and high tide
Called a spring tide – occur twice a month during full and new moons

18. Neap Tides
During moon’s 1st and 3rd quarter, line between Earth and the sun is at right angles to line between Earth and moon.
Sun’s pull is at right angles to moon’s pull.
Produces a neap tide = least difference between high and low tide
Occur twice a month

19. Spring Tides and Neap Tides