Turn your classroom floor into underwater terrain and experiment with charting your own ocean floor.

• First, have small groups each make a miniture version of a sounding line by knotting a length of string at regular intervals and tying a lead fishing weight to the end.
• Next, have each group create a mini ocean floor terrain (with reefs, shallows, etc.), using objects of different shapes and sizes.
• Take turns using the sounding line to chart the terrains and record your measurements in your journal.
• As you conduct this experiment, analyze why the Endeavour was shipwrecked on the Great Barrier Reef if the sailors had the ability to use sounding lines.