Infrared Thermometer
Measure Temperature Quickly and Without Contact!
A new addition to our line of sensors is an infrared thermometer. The sensor works by measuring the infrared radiation emitted by objects. For most objects, you simply point the sensor at the object and read its temperature. Our Infrared Thermometer features automatic backlighting, simple ON/OFF operation, and laser sighting.
The laser sighting circle is a valuable feature because it allows you to see the area from which the measurement is being made. The sensor can be used as a stand-alone meter, or it can be connected to a data-collection interface, such as Vernier LabPro®, Go!® Link, CBL 2, and Vernier EasyLink®, allowing data to be recorded on a computer, Texas Instruments graphing calculator, or Palm Powered™ handheld. Below are some ideas for use of the sensor.
Infrared Thermometer | Order Code IRT-BTA | $159
Available October 1, 2006
Understanding Temperature
Temperature can be a difficult concept to understand. Our personal experiences complicate the situation. Imagine being a grade school student in a classroom on a hot day in September. Your arm touches the metal leg of the desk, and you discover that the metal is cold. When you touch the top of your desk, it's not cold. As a matter of a fact, most of the objects in the room are not cold. The Infrared Thermometer is a perfect sensor for this teachable moment.
A student could use it to discover that the temperature of the metal leg of the desk is the same as the desk top, which is the same as the temperature of the wall, door, textbook, etc. This knowledge helps students better understand temperature and equilibrium. This experiment could lead to a field trip to the school's parking lot. With the sun shining brightly on the cars, the students could compare the temperatures of the surfaces of cars. Are these temperatures the same, or does the color of the car make a difference? Is the surface of the car hot enough to fry an egg? Students could expand their exploration to compare temperatures of the lawn, concrete, and asphalt.
The Drinking Bird Demo
You are probably familiar with the "Drinking Bird" toy, shown above. The bird sits on a stand that allows it to rotate about a pivot point. After the head of the bird, which is covered with felt, is wetted, the bird oscillates about the pivot point while a liquid moves up and down a tube connecting the head and bottom of the bird. A number of concepts can be discussed when explaining the motion of the bird—center of gravity, vapor pressure, temperature, and equilibrium, among others.
An important part of the explanation centers around understanding what happens to the temperature of the bird's head. Since the head is covered with moist felt, we can hypothesize that evaporation is occurring at the bird's head. Since evaporation is a cooling process, the head must be cooling, and the drop of vapor pressure in the bird's head contributes to the rise of the liquid in the tube.
Without this sensor, you don't have direct evidence that the bird's head is cooling. With this sensor you can verify the hypothesis. We tried it and found that the temperature of the felt before adding water was 25°C. We measured the temperature again after wetting the head and letting the bird oscillate for 10 minutes. The temperature had dropped to 19°C.