1. Tides

2. 1. Tides-What are they?

3. Mont Saint Michel France

4. Tides Tides are the regular rise and fall of ocean water levels.

5. 2. What causes tides to occur?
Tides are due to the gravity of the moon trying to pull the water on Earth closer to it (the moon).

6. What causes tides to occur?
The sun also pulls on the water, but it is farther away, so it doesn’t have as much as an effect.

7. Gravitational Pull
Gravitational pull depends on the mass of the object and its distance from Earth

8. What would happen to our high tides if the moon were more massive (bigger)?
Tides would be higher because the moon would have a greater gravitational pull on them

9. What would happen to our tides if the moon were further away?
Tides would be smaller because of less gravitational pull

10. Earth rotates every 24 hours, which means that the places on Earth where high tide and low tide occur are always changing.

11. Watch the tide change in Africa

12. High Tide to Low Tide takes about 6 ¼ hours
Knowing this will help you set up your beach chair in the right place!
(fishing under ice at low tide)

13. 3. Spring Tide
When the Earth, Sun, and Moon are in a straight line (new moon and full moon) their gravitational force is combined and you have extra high and extra low tides called “Spring Tides”

14. 4. Neap Tides
When the Sun, Earth, and Moon are at a right angle (1st and 3rd Quarter) the gravitational pull is not as strong and tides are not as high or low as normal, this is called a “Neap Tide”.

18. Review Questions

19. If low tide is at 9am, when will high tide happen?
Add 6 ¼ hours (6 hours and 15 minutes)
3:15pm

20. If high tide is at 8pm, when would the next high tide occur?
Add 6 ¼ hours to get to low tide
Then add another 6 ¼ hours to get back to high tide.
8:30am

21. Which diagram produces the highest tides? Explain
B; Because the moon is in a new moon phase and the moon and sun’s gravitational pull are combined. A B

22. If the moon were closer, what would be the effect on our tides?
Higher tides because a closer moon would have more gravitational pull

23. Life as We Knew It
Summary: A family’s experience with what would happen to our lives on Earth if the moon were hit by a meteorite and pushed closer to Earth.

24. If the moon were larger, what would be the effect on our tides?
Higher tides because a larger moon would have a greater gravitational pull.