Every day, no matter where you are, you will see people using their cell phones. People use their cell phones for more than just making calls though. They use them for texting and searching the Internet, too. But some health groups are concerned that using your cell phone too much can be hazardous to your health. In this electricity and electronics science project, you will investigate whether your cell phone emits dangerous levels of microwave radiation when used for calling and texting. just about everywhere you go, you can see someone using a cell phone. You can use a cell phone to call your mom to pick you up from the mall, text your best friends, check the Internet for movie times, and even play games. The cell phone is an important part of how we communicate with our friends and family.
But how does a cell phone do all of that? Cell phones are basically radios that depend on radio signals to receive and transmit information. When you talk into your cell phone, it converts your voice into a microwave frequency signal. Cell phones transmit and receive information at microwave frequencies, which are within the radio frequency (RF) spectrum. Radio waves and microwaves are all part of the electromagnetic spectrum. See Figure 1 to view the full electromagnetic spectrum. Each cell phone carrier (like Verizon, AT&T, etc.) is given a set of frequencies, which they use to transmit and receive information in a typical city. Each cell phone carrier then breaks the city up into cells (each cell is a few square miles). Each cell has a base station. When you turn on your cell phone, it communicates with its closest base station and shares information about you and where you are located. When you make or receive a call from a friend, many operations have occurred that identify where and who you and your friend are, determining which microwave frequencies your phones should use so that you can both talk. Once the connection has been made, having a conversation on the phone is like talking on a two-way radio.
When you use your cell phone to talk or text, your body absorbs some amount of the microwave frequencies, and there might be some health issues associated with this. The electromagnetic spectrum is classified into non-ionizing radiation and ionizing radiation. Non-ionizing radiation does not damage the genetic material in body's molecules, and might or might not cause illness (more on this in the next paragraph), but if the exposure to microwave radiation is sufficiently intense (which you can read more about in the Office of Engineering and Technology reference in the Bibliography, below), then it can cause biological damage, such as burns and cataracts. Ionizing radiation, on the other hand, is dangerous to our bodies, and in high doses can cause cancer and birth defects. Radio frequencies and microwave frequencies are classified as non-ionizing radiation, and x-rays and gamma rays are examples of ionizing radiation.
There is a lot of debate about whether or not the radiation (the microwave frequencies that the cell phone is receiving and sending) from cell phones is harmful to humans. Since the cell phone is held close to the head, many scientists are studying whether the rise in cell phone usage is creating a rise in brain tumors. There have been a lot of studies done, but the results have been inconclusive. . The Federal government has set the maximum exposure to microwave radiation at 5 milliwatts (mW) per square centimeter 2 inches from the device. The maximum exposure is also called the specific absorption rate (SAR) and the unit of measure is in watts per kilogram (W/kg).
Defining Terms * Frequency * Electromagnetic spectrum * Radio wave * Microwave * Absorb * Non-ionizing radiation * Ionizing radiation * X-ray * Gamma ray * Watt
To investigate if your cell phone emits microwave radiation, and to determine the level of