Thermodynamics: Vaporization
Determine the amount of thermal energy contained in a specific quantity of steam (one gram) at a specific temperature (100°C). This amount of thermal energy is called the Latent Heat of Vaporization of water.
Students use the graph to determine the initial and final temperatures, so that they can calculate teh change in heat energy.
Lab Summary
The phase change from gas to liquid involves a transfer of thermal energy out of the substance, but doesn't involve a temperature change for the substance. The thermal energy depends on the mass and the latent heat of vaporization (the amount of energy per gram needed to change phase at a specific temperature). Your students will measure temperature and the mass of condensed water to determine the energy required to transition water from gas to liquid, and compare this to the energy required to simply change the temperature of water.
Theory
The energy contained in 1 gram of steam at 100° C is called the Latent Heat of Vaporization of water. Using a steam generator and collecting that water as it cools allows a simple measurement of the change in water temperature which is used to calculate the heat of vaporization.
Downloads
- Download Free Lab (PDF, 1.2 MB) (1.15 MB, .pdf)
(student version)
Method
Use a Fast-Response Temperature Probe to measure the change in temperature of a known mass of water as steam changes from gas to liquid in the water. Determine the latent heat of vaporization of the steam.
Here's What You Need
U.S. Educator prices shown.
Probeware
PASPORT Fast Response Temperature Probe (3 pack) (PS-2135) - $29
Allows students to see changes in temperature they could never see before. For use with PASPORT and ScienceWorkshop Interfaces.
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
Other Products
Basic Calorimetry Set (TD-8557A) - $129
Students can determine the specific heat of a substance, the latent heats of vaporization, and fusion of water.
Ohaus Triple-Beam Balance (without Tare) (SE-8723) - $147
This Ohaus triple-beam mechanical balance (without tare) is accurate and easy to use. This balance has been a standard weighing instrument in student laboratories for decades.
Other Materials
- Glass tube, 1/4" outside dia., 2" long
- Water, about 10 deg C cooler than room temperature, 1 L
Lab Manual
This activity is included in Physics with the Xplorer GLX (PS-2826), complete with Teacher Information pages, student instructions and handouts, and sample data for a total of 35 probeware-based labs. For your convenience, we offer bundles which provide the probeware necessary for the activities in the manual. For more information on these resources and bundles, click here.
