In the short time they've been around, cell phones have changed the world. Just 20 years ago -- if you can believe it -- you had to discuss dinner plans before you arrived at the grocery store. Also, you didn't have to field work calls until you were actually at work.
Cell phones gave us new ways to stay connected. For some, they also provided a new reason for worry. Cell phones release microwave radiation when they're in use, a fact that inevitably led to fears of brain cancer.
Just as inevitably, worries about brain cancer spawned a market for products that supposedly protect cell phone users. For $62, you can order a Delta Shield, a thin polyester patch that contains a microchip that allegedly renders cell phones harmless. Users are instructed to place the patch on their cell phone battery. The similar BIOPRO Cell Chip, sold online for $35, attaches to the outside of the phone. The penny-size WaveShield 2000 Gold, selling for about $25, fits on the earpiece.
The claims: The Web site for the Delta Shield claims that it is "the only cell phone protection device that has proven efficacy." An unpublished scientific paper highlighted on the site supposedly shows that the device can convert harmful delta brain waves to helpful alpha waves.
One site selling the BIOPRO Cell Chip site says its patented technology "has been proven in numerous scientific studies to neutralize the dangers of electromagnetic radiation from cell phones and other devices."
The site goes on to explain that the device "superimposes a low-frequency 'noise field' on [electromagnetic radiation] that resembles the natural resonant frequencies of the body's living cells. This effectively renders EMR harmless."
The bottom line: "Most [experts] think these devices are worthless," says Richard Kaye, a former San Diego-based chiropractor and a Delta Shield business consultant.
Though Kaye is convinced the product works -- for one thing, he says, the side of his head no longer gets warm when he uses his cell phone -- an independent expert did, indeed, reach the opposite conclusion.
"It's a scam," says Robert Park, professor emeritus of physics at the University of Maryland and author of "Voodoo Science: The Road from Foolishness to Fraud," published in 2000. "The claims they're making aren't very clear, but they are certainly wrong," he says. "I'd stake my reputation on it, such as it is."
Claims of "natural resonant frequencies" may seem impressive but, Park says, "people have been talking about natural resonant frequencies for years, but I still don't know what that is. It's a meaningless statement."