Tides

Oregon Coast

Tides

• Tides are NOT created by Wind.• Tides are created by gravitational attraction of the Earth and the Moon and the Earth and the Sun.

• High tide= elevation of Earth’s water is high

• Low tide= elevation of Earths water is low

Monthly Cycles: Spring and Neap Tides

Spring tidesThe greatest range of tidal eleva-tion during the month. Spring tides occur around full and new moons.

Neap tides The smal-lest range of tidal ele-vation. Neap tides occur around first and third quarters of the lunar cycle.

Spring Tide

Neap Tide

Why tides occur• Together, the gravitational pull of the moon and the sun affect the

Earth’s tides on a monthly basis.

• When the sun, moon, and Earth are in alignment (at the time of the new or full moon), the solar tide has an additive effect on the lunar tide, creating extra-high high tides, and very low, low tides — both commonly called spring tides.

• One week later, when the sun and moon are at right angles to each other, the solar tide partially cancels out the lunar tide and produces moderate tides known as neap tides.

• During each lunar month, two sets of spring and two sets of neap tides occur.

How often do tides occur?• High tides and low tides occur twice a day in

most areas.

• Spring tides and Neap tides occur twice a month.

1. Surfs up

Left side:• You and your surfboard are looking for an

awesome wave to catch.• Pretend that it was a first quarter moon on

July 1st.

1. Give what time of day and day of the month would have the most bodacious waves.

2. Is this neap, spring, or neither tide?

PreAP

2. Sand castles

• You are entering a sand castle contest for a 1 b’jillion dollar prize. The best sand castles are made on the wet sand at low tide.

• Pretend that it was a new moon on August 1st.

1. Give best date and time to build this sand castle.

2. Is this neap, spring, or neither tide?PreAP

1. Surfs up

Left side:• You and your surfboard are looking for an

awesome wave to catch.• Pretend that it was a new moon.

1. Give what time of day has the most bodacious waves.

2. Is this neap, spring, or neither tide?

R

2. Sand castles

• You are entering a sand castle contest for a 1 b’jillion dollar prize. The best sand castles are made on the wet sand at low tide.

• Pretend that it was a 3rd quarter moon.

1. Give best time to build this sand castle.

2. Is this neap, spring, or inbetween tide?

R