During winter in the Northern Hemisphere, Arctic air temperatures often dip below what we normally think of as the freezing point of water. Yet, while freshwater lakes freeze over, much of the ocean stays in liquid form rather than freezing into ice. Why doesn’t ocean water freeze at the same temperature as fresh water?
In this experiment, you will use a Temperature Probe to measure the temperature of water as it cools and then freezes. In Part I, you will collect temperature data as you freeze fresh water and determine its freezing temperature. In Part II you do the same for ocean water. You will then compare the two freezing temperatures and hypothesize why they are different.
In this experiment, you will
Observe the freezing of fresh water and ocean water.
Use a Temperature Probe to measure temperature.
Determine the freezing temperature of fresh and ocean water.
Sensors and Equipment
This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):
Step-by-step instructions for computer-based data collection
List of materials and equipment
Note: The experiment preview of the computer edition does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.