Tide Definition: The rise and fall of the surface level of the ocean. Occurs twice each day.

What causes these tides? Tides are caused by the gravitational pull from the moon and from the sun.

Frequency How many tides are there in 24 hours? There are two high tides and two low tides.

High Tide When the water level is at its highest level. Maximum flow of water on the beach.

Low Tide When the water level is at its lowest level. minimum flow of water on the beach.

Ebb vs Flood Flood - High flow of water. Ebb - Low flow of water

Nautical Terms ( Nautical Nonsense ) Rest – The period of time between high and low tide. Slack – The period of time when the water level is at its highest point or lowest point.

Types of Tides As the moon revolves around the sun it creates two extreme types of tides. Spring Tide – Extreme high tide and extreme low tide Neap tide – Lower than normal high tide and higher than normal low tide

Spring Tide The water level at high tide is at a higher level than the normal high tide level. The water level at low tide is at a lower level than the normal low tide level.

Neap Tide The water level at high tide is at a lower level than the normal high tide level. The water level at low tide is at a higher level than the normal low tide level.

Review

Summary Using the red “Earth Science” text book, notes from the PPT, and the video write a half page summary explaining how tidal movements occur. Read pages 492 – 496 in Earth Science textbook.