Materials
computers with Internet access
calculators


Background
The novel by Nathaniel Philbrick, In the Heart of the Sea: The Tragedy of the Whaleship Essex, chronicles the tragedy of the crew of the Essex, specifically when the crew was stranded on a island in the Pacific where the crew had to calculate when the fresh water would be exposed enough to gather water to supply the crew.

In this lesson, students will be charged to determine similar calculations using real time data.


Procedure
Problem Statement
You and the 7 other crew members of your boat are stranded on an island.  The only source of fresh water is an aquifer whose outlet is on the rocky coast and is only accessible during an extremely low tide, lower than -2.0 feet to MLLW.

Your challenge is to determine when the low tide will occur to collect fresh water.  Calculate how much water people will need per day to survive (The World Health Organization has a guide for daily water requirements).  Then, determine when the next low tide will occur so that you can calculate the total amount of fresh water needed to sustain the crew.

1.  You and your 7 crew members are stranded on Kodiak Island for the next 3 months.  Will there be a tide low enough to collect fresh water?  How much will you need to collect to sustain the entire crew until the end of the three month period, or until the next low tide, which ever event arrives first.


Assessment
The prediction results.