Thermometers are such a common object in today’s world that chances are you have given little thought as to the varieties of them or how they work.  If you are visually impaired or blind you might have even given up on most of them all together. This blog will look at three different types of thermometers marketed to the visually impaired to better help you keep track of outdoor (and possibly indoor) temperatures.

Classic Dial Thermometers

Classic dial thermometers have a metal pointer that moves up and down on a circular scale. If you were to open it up, you would see that the pointer is mounted on a bimetallic spring-like coil that is designed to expand and bend as it gets hotter. As temperature increases or decreases the bimetallic strip expands or contracts rotating the pointer around the fixed dial. The dial thermometer goes back to at least 1905 when Charles W. Putnam patented the device. If this type of thermometer interests you check out this 18” Big and Bold Thermometer from ILA. This version mounts on a wall, can be used either indoors or outdoors, and has large digits to be more easily read.  Temperature readings are shown in both Fahrenheit and Celsius as outlined on the face.

Digital and Wireless Thermometers

Digital (or electronic) thermometers offer easy-to-read displays and tend to have affordable pricing. These type thermometers work in an entirely different way to mechanical ones that use lines of mercury or spinning pointers. They contain a small computing mechanism and a resistor based on the idea that the resistance of a piece of metal (the ease with which electricity flows through it) changes as the temperature changes. As metals get hotter, atoms vibrate more inside them, it is harder for electricity to flow, and the resistance increases. Similarly, as metals cool down, the electrons move more freely, and the resistance goes down. A change in temperature causes the sensor to notice a change in resistance. The computer will then calculate the difference of resistance into a temperature and produce a digital readout in degrees. (See Thermometers to learn more) If you are looking for a thermometer of this kind, ILA offers the Talking Indoor/Outdoor Thermometer Dual Display. Conveniently sized, this thermometer can easily be used either on a desk or hung on the wall. It has a large dual display that shows both the indoor and outdoor temperatures and announces them verbally at the push of a button. It can be set to make announcements automatically every hour on the hour and can even be programmed to announce the temperatures at a pre-set time in order to act as a wake-up alarm. It will announce the temperatures in Fahrenheit or in Centigrade, at the flip of a switch. The indoor temperature probe is built into the unit. The out-door temperature probe (remote probe) is connected to the unit by a cable and should be placed outside the house. (See full instructions for more information)

Digital Clock/Thermometer Combos

In addition to having digital (or electronic) thermometers, these combos also have digital clocks, and in some cases atomic clocks as well.  In a nutshell, digital clocks work through use of a glass crystal oscillator. When an electric charge is sent through the crystal it changes shape very slightly and creates a very slight sound. The sound is at a regular frequency which is converted to an electronic signal. When a digital clock clicks over from 12:59 to 1:00 it must be reset to, in effect, start over. Most digital clocks will be equipped with a built-in processor looking for the number 13 in the hours column and when this occurs sets the hour counter back to 1. (See How Digital Clocks Work for a more detailed explanation.) Atomic clocks, however, work in a different way. With an error of only 1 second in up to 100 million years, atomic clocks are among the most accurate timekeeping devices in history. In an atomic clock, the natural oscillations of atoms act like the pendulum in a grandfather clock. However, atomic clocks are far more precise than conventional clocks because atomic oscillations have a much higher frequency and are much more stable.  (See How Does an Atomic Clock Work by Time and Date for more details) The first quality atomic clocks made in the 1950s were based on cesium, and such clocks honed to greater precisions over the decades remain the basis used to keep official time throughout the world. In the United States, the top clocks are maintained by the National Institutes of Standards and Technology (NIST) in Boulder, Colo., and the United States Naval Observatory (USNO) in Washington, D.C. (See How Does an Atomic Clock Work by LiveScience for more details) One of the digital clock/thermometer combos offered by ILA is this Atomic Talking Clock w/Alarm, Calendar and Wireless Outdoor Temperature Sensor.  This extraordinary talking atomic clock includes the most important features you need to keep you on track all day. It speaks all the functions to guide you through the settings and it will announce hourly either the time or the temperature. For those with some vision, the time is displayed with large numbers and the date, indoor and outdoor temperatures are shown as well. (See full instructions for more information) To see what’s currently on sale at ILA please sign up for our newsletter, view our Facebook page, follow us on Twitter, or visit our website.