Answer Man: What do the silica gel packets do?

News-DemocratFebruary 4, 2014 

I've opened a million packages over the years and found small packets of silica gel. What are they used for? -- T.M., of Edwardsville

On a list of dry subject matter, you've managed to ask about one of the driest.

You call them "silica gel packets," but they are often labeled with the word "desiccant." It means "drying agent," because that's exactly what they do -- protect the contents of whatever you've purchased by adsorbing and holding water and other vapors.

Commonly found in nature as quartz, silica gel is purified and processed into either a granular or beaded from used in those packets. With its porous structure and great affinity for water, it can adsorb about 40 percent of its weight in moisture. That would be like a 180-pound man guzzling and then retaining 9 gallons -- 72 pounds -- of water.

For a variety of companies, this can be crucial, which is why you find them so often. In leather and food products, reducing moisture can limit mold growth and retard spoilage. Since condensation could fry your Blu-Ray or laptop, they're packaged in electronics. And since moisture is a bane of vitamins and other medicines, you fish them out of pill bottles.

Just a scientific curiosity when it was first noticed in the 1600s, it became a lifesaver in World War I as the active ingredient in gas masks. Once chemistry professor Walter Patrick at Johns Hopkins University found a way to produce it synthetically, silica gel became even more important in World War II as it kept penicillin dry, protected equipment from moisture and helped produce high-octane gasoline.

Now, its list of uses seem endless. Since the pure form is usually nontoxic, it is often added to food products as an anti-caking, anti-settling and defoaming agent. Naturally, it's a perfect additive for clumping cat litter. But NASA used a silica-based gel on its 1999 Stardust mission to collect cosmic dust and it's sometimes utilized to extract RNA and DNA because of its binding properties.

In fact, you can build your own cheap dehumidifier by buying silica gel, which is available at many craft stores because it is used to dry flowers. Fill a container with the gel and let it go to work. When you find that your humidifier has adsorbed all the moisture it can, shake the gel onto a cookie sheet and bake it at 300 degrees for three hours. After it cools, the gel can be reused.

Warning: Not all silica gel is safe if ingested. The gel in those packets may be laced with chemicals that cause the gel to change colors when fully saturated.

Over the past few weeks, I have numerous emails from unknown persons claiming a delivery could not be made even though I ordered nothing. An attachment was included in each instructing me to open for details. Is there danger in opening these attachments? -- R.B., of Fairview Heights

For those still getting their feet wet in the world of computers, there are three commandments you should always obey, according to my high-tech goddess, Kim Komando.

First, never, ever, ever open an attachment you weren't expecting -- not even if the return e-mail address is your mother's.

You may have found that you sometimes get spam messages from people you know because your friend's e-mail addresses have been stolen by a virus that has wormed its way into someone's address book. The virus then uses the names it finds to spit out bogus e-mails. Any virus-riddled attachment that is opened could launch a potentially fatal attack on your computer. Again, delete all email with unexpected attachments.

Second, install anti-virus software and keep it updated. You don't have to spend a bundle. It's free at free.avg.com. But do it.

Finally, back up your files every time you modify them. A hard drive can die at any time, so you don't want to risk losing all those precious pictures, music and data. Personally, I coughed up the bucks for Carbonite because it backs my files up automatically every day, but do it somehow. I've seen too many people cry over dead drives.

My other general suggestion is to simply delete any email if the address looks strange to you. I don't think merely opening an email poses a risk yet, but criminals are always finding new ways to invade your computer, so why take the chance? And, like answering a junk call, some say merely opening spam tells people you're out there and they'll send you more.

Besides, nobody in Tanzania has left you $5 million in his will. Yet just the other day, I receive an official looking message from "Erick Bolt" of the FBI, alleging that I may be part of a $4 million money-laundering scheme. Do your really think the IRS or FBI is going to contact you by email out of the blue? That's what the "delete" key is for.

Today's trivia

How many gallons of beer does a typical U.S. keg hold?

Answer to Tuesday's trivia: For the most Grammy-honored albums in history, buy U2's "How to Dismantle an Atomic Bomb" and Santana's "Supernatural," which won nine each. Michael Jackson's "Thriller," Norah Jones' "Come Away With Me" and Ray Charles' "Genius Loves Company" earned eight.

Send your questions to Roger Schlueter, Belleville News-Democrat, 120 S. Illinois St., P.O. Box 427, Belleville, IL 62222-0427 or rschlueter@bnd.com or call 618-239-2465.

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