1. Tides
LOW TIDE HIGH TIDE

2. Tides
Tides are rises and falls in ocean water that cycle every 12.5 hours.
Rises for about 6 hours
Falls for about 6 hours
Why do you think this happens?

3. Tides
The force of gravity pulls the moon and Earth (including the water on Earth’s surface) toward each other.
Tides occur mainly
because of differences
in how much the moon
pulls on different parts
of the Earth.

4. Tides
As the Earth rotates, the moon’s gravity pulls water toward a point on Earth’s surface closest to the moon.
This causes a second high tide on the other side of the Earth.

5. Tides As Earth rotates, tides occur in a 25-hour cycle.
The shape of bays, inlets, and the ocean floor can affect the flow of water, and cause tides to be irregular in some areas.

6. SPRING TIDES
Spring Tides occur whenever the Sun, Earth and Moon are most closely in a line. Spring Tides normally happen two times a month, once during a New and once during a Full Moon. Spring Tides tend to be higher than normal high tides. SPRING TIDE = OLD ENGLISH word meaning “to jump.”

7. NEAP TIDES
Neap Tides happen when the Sun and Moon are at right angles to each other. Neap Tides also happen twice a month during Quarter Moons. Neap Tides create lower than normal high tides.

9. Tides can be used to create electrical energy!

11. Checkpoint!
What objects create the force that gives Earth’s oceans tides?