Using the Infrared Thermometer to measure temperature

Is the heat given off by 500 people enough to change the temperature inside a large auditorium? How does the temperature and salinity of a tide pool compare to that of the nearby ocean water? These were just two of the questions posed to about 250 students from 52 countries who gathered in Cape Town, South Africa, this summer for the GLOBE Learning Expedition (GLE). And of course, Vernier equipment was used to investigate the answers to those questions.

GLOBE is a worldwide community of students, teachers, scientists, and citizens working together to better understand, sustain, and improve the Earth’s environment. Every few years, these groups of people converge at the GLE to share their projects and their love of science. During the opening ceremonies at the University of Cape Town, Chief Scientist Dr. Peggy LeMone asked the audience whether they thought the 500 people in the auditorium were enough to warm the air and, if so, by how much. She then revealed that a Vernier Go!Temp had been collecting data on her computer for the past hour and she projected the resulting graph shown in Figure 1.

The conference had barely started and everyone was already doing science!

Fig. 1 Warming of the auditorium as people entered

Over the next few days, teams of students presented the GLOBE-related projects they had been working on in their own countries. Between sessions, they had time to relax and enjoy using some of the Vernier equipment, such as this group from South Africa having fun with LabQuest and an Infrared Thermometer.

Dias Beach and the Cape of Good Hope
Students from four countries measure temperature and salinity

The final two days were spent on field expeditions to various locations around Cape Town. The Vernier field location was at a set of tide pools on beautiful Dias Beach, adjacent to the Cape of Good Hope.

Approximately 250 students used Vernier LabQuests and sensors to measure temperature, salinity, dissolved oxygen, and pH of the tide pools, and compared the results to the nearby ocean water.

When asked to predict the differences in temperature and salinity between the two, the students invariably predicted that the tide pools would be warmer and more saline than the ocean water.

The results, however, showed the opposite to be true (see Fig. 2). Students reevaluated the environment and realized that these tide pools were in constant shade, nestled in cold rock (the IR Thermometer showed the rock to be 12°C), and there had been rain since the last high tide, diluting the salt water with fresh water.

Fig. 2 Temperature and salinity comparisons near the Cape of Good Hope

Vernier enjoyed bringing hands-on science to the GLOBE Learning Expedition, and we look forward to next time!

For more information on GLOBE, visit