Build a model of an historic log and line to see how sailors used dead reckoning to determine their ship's speed. Accurate, though imprecise, this model will calculate your walking speed in knots and show you the origin of that terminology. A fun and different way to explore the speed = distance ÷ time equation.
Use this to learn and reinforce answers to questions such as:
❑ How did ancient sailors calculate their ship's speed?
❑ What do we need to measure to determine our speed?
❑ How fast is a knot of speed?
Once students work through the activity, they can capture their observations using the included Lab Notes or probing questions included in the instructions.
Concepts Addressed
♦ Speed is a measure of distance per time
♦ Speed can be measured in knots
♦ Slower ships take more time to cover a given distance
TEKS
6.8C, 8.6A
VA SOL
ES.1.c, PS.1b., PS.1m., PS.10a.
Answer Keys and Teacher Notes address most questions and issues that might arise in this study—you shouldn’t have to do any outside research unless you want to.
Materials Needed: Flat board (clip board works fine), cardboard tube, dowel (about 50 cm) string (30 m), 10-second timer (phone or digital timer), sand timer for reference (optional)
Teaching Time: 30 min
Prep Time: Measure and tie knots to the string and tape it to the board and tube.
Student Sheets Scaffolded writing prompts & lab reporting
