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This Actvity investigates the claim that the temperature of the surrounding air can be found by applying a simple rule to the number of chirps a cricket makes in a period of time.
To test the claim we need to be able to count the chirping rate of a cricket (of course!). Unfortunately, most crickets chirp too rapidly (about 25 ms apart) for our ears to distinguish between each chirp. There is a cricket in the United States which is called the "thermometer cricket" (snowy tree cricket, Oecanthus fultoni ) which appears to chirp in regular groups at a frequency that can be easily counted. The java applet below can be used to collect some data about the number of chirps the cricket makes at differing temperatures.
Instructions
Use the applet to find the number of chirps the cricket makes in 8 seconds for about five different temperatures. You may find it more accurate to count the trills (chirps) over a longer time period and convert the count back to 8 seconds. Put your data in a suitable table as described in question 2 below.
Start the investigation by clicking the "Start" button. Next, select a temperature between 10oC to 40oC by sliding the red scale on the thermometer. After clicking the "Listen" button you will hear the trill of the snowy tree cricket at that temperature. Once you have become used to the frequency of the trill, click the "Timer" button to start the stopwatch.
Once you have gathered the data on the chirping pattern of the snowy tree cricket, answer the questions below.
Use the questions below to help analyse the data.
- This Applet gets you to collect data on two variables. What are these, and how are they measured?
- Draw up a table for these variables. Call the first column "Chirps in 8 seconds" and the second column "Temperature in oC".
- We are investigating whether we can tell the temperature if we know how often the cricket chirps. Which of these variables depends on the other? Does the temperature depend on the number of chirps or is it the other way round?
- Describe all the possible temperature values that seem sensible in this investigation. The investigation restricts the temperatures you can use to 10oC to 40oC. What range of temperatures seems sensible in nature?
- Now describe the possible values for Chirps. Are there any restrictions?
- Plot the values in the table on a graph. Make the horizontal axis "Chirps per minute" and the vertical axis "Temperature in oC". Use the graph to find answers for the following.
(a) The points appear to form an obvious pattern. Join the points to best fit the pattern.
(b) Explain why it makes sense to join the points. Do you think that other values can exist continuously between the points or are only certain points allowable?
Challenge for Champions
- Can you find a rule that works out the temperature if you know the number of chirps the cricket makes in 8 seconds? You might like to work in a group to make a chart of your findings to present to your class.
More on Insect calls.
If you would like to know more about cricket calls, visit here.
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