Answer to Question #10832 Submitted to "Ask the Experts"

Category: Cell Phones

The following question was answered by an expert in the appropriate field:

Q

What type of instrument can be used to measure radiofrequency (RF) exposure from a cell phone? This is for a fifth grade science experiment, so hopefully it's an inexpensive tool.

A

Unfortunately this is not something that a fifth grade science experiment can replicate. The measurement for the absorption of energy to the human body is in Watts per kg or the energy deposited per unit mass. In the instances of Specific Absorption Rate (SAR) measurements from cell phones all of the equipment necessary to conduct these tests is quite expensive and costs perhaps as much as $1,000,000. The Federal Communications Commission normally provides the results of cellular phones and this can be searched on its website under “cell phones and SAR.” You can view a video that provides a great explanation as to how SAR testing is performed.

While the actual testing of the SAR from a cell phone is done with an electric field probe and computer modeling, at its basic foundation this is a very fancy calorimeter. Perhaps as a substitute to measuring the RF exposure from a cell phone you could conduct an experiment in measuring the heat absorption from a source and equate to the students how this is essentially accomplishing the same goal as the SAR testing for a cell phone.

Drew Thatcher, CHP

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