Wilmington, NC

Dauphin Island, Al

Alcatraz Island, CA

Observe your tide Notice the tide graph is for 1 week 10/ /25 Notice that your tide graph has high points and low points Notice that the time is marked in 6 hour intervals

During each 24 hour period from 4/3 – 4/9: Label your tide graph with the following terms: High-high – highest level/24 hrs Low-high – lower high tide/24 hrs High-low – higher low tide/24 hrs Low-low – lowest level /24 hrs

Types of tides Use the following definitions to determine what type of tide yours is and label it on the top. Diurnal Tides - A single high and low tide each lunar day Semidiurnal Tides - Has two high tides and two low tides each lunar day. The heights of successive high tides and successive low tides are approximately the same. Mixed Tides - Successive high tides and/or low tides will have significantly different heights

Explain your Decision Now, take turns explaining to the other members in your group why you have defined your tide as you did. On the front of your graph, write the definition of your tide. On the back of your graph sketch and label the two other tides with their definitions.

Group discussion: On each tide graph find the highest high tide. Within your group, discuss why the high tide increases or decreases throughout the week. Now, predict where along the U.S. coastlines you would find each of the three types of tides.