Activity Overview
Students compare the heating rates of wet sand and dry sand and study the effect of evaporation on heating rates. They create, interpret and analyze graphs of data. They also relate slope to rate of change.
Before the Activity
Connect CBL 2™ to the calculator.
Plug the temperature sensor into channel 1 of the CBL 2
Launch the DataMate program
See the attached PDF file for detailed instructions for this activity
Print pages 58- 59 from the attached PDF file for your class
Transfer files to student calculators using TI-Navigator™ "send to class" feature
During the Activity
Distribute the pages to your class.
Follow the Activity procedures:
Make two trays of 500 ml dry sand
Add enough water in one tray to dampen the sand
Keep the initial temperatures of the sand in the two containers the same
Bury the end of the temperature sensor 0.5 cm below the surface of the dry sand
Place the heat lamp 20 cm above the tray of sand
Measure the temperature at 30 second intervals for 5 1/2 minutes
Repeat the same steps with wet sand
Graph the temperature data
Slopes of the lines on the graph represent the rate of heating of the sand
The steeper slope of the dry sand indicates that the rate of heating is faster than the wet sand with the less steep slope
Understand how adding water keeps the temperature of the sand cooler for longer
After the Activity
Students analyze the results and answer the questions in the worksheet
Review student results:
As a class, discuss questions that appeared to be more challenging
Re-teach concepts as necessary