Observations and results
Was the temperature based on the cricket's chirps close to the actual outdoor thermometer temperature, and maybe off by only a few degrees F?
As far back as the late 1800s there have been articles published noting that a cricket's chirp rate (or number of chirps per second that it makes) changes consistently based on the outdoor temperature. There have been many equations published describing the relationship between the number of chirps per second and the temperature. These equations all vary slightly, depending on the species of cricket. Using this activity, you may have found that the cricket was within about 5 degrees F of the temperature measured using the outdoor thermometer, and probably even closer than that. If you repeated this activity multiple times and found that, based on the cricket's chirps, it's was colder than the thermometer read, this could be because the cricket was farther away from a warm building than the thermometer was, and/or because the cricket was closer to the cold soil. The snowy tree cricket is frequently cited as the most accurate at predicting temperature. If you want to listen to examples of it chirping under hot, warm, cool and cold conditions, check out the resource on the "Snowy Tree Cricket" in the "More to explore" section below.
More to explore
Snowy Tree Cricket from Professor Thomas Walker at the University of Florida
Field Cricket from Great Plains Nature Center
Rate Constants and the Arrhenius Equation from Jim Clark at Chemguide
The Arrhenius Equation from Shodor in cooperation with The University of North Carolina at Chapel Hill
Ask a Cricket, "What Is the Temperature?" from Science Buddies
This activity brought to you in partnership with Science Buddies