Lab

Supplies: 

A small cardboard box about the size of a plastic milk crate—no cost 

One clear plastic paint drop cloth—cost about $1.00 

One electric coffee mug warmer—Wal-Mart about $4.00 

Two tubes of “Super Glue” of any brand. Best not to use the gel type. Cost about $1.00 

One small square (1” X 1”) of aluminum foil—No cost 

One old coffee cup or juice glass—no cost 

“Evidence”—used soda can and a glass—no cost 

Scissors—No cost 

Hot water 

Instructions: 

Super glue fumes can be very unpleasant; causing irritation to eyes and smelling badly. They will not harm you as a result of limited exposure. Even so, you may want to conduct this lab outdoors in a well-ventilated area. 

Cut the top out of the cardboard box, leaving all four sides and the bottom. 

Cut a piece of the clear plastic from the drop cloth large enough to cover the top of the open cardboard box, reaching to ground or table top when draped over the box. 

Place the coffee mug warmer into the box, sitting it in one corner on the bottom of the box. Turn it on (will not set fire to the box). 

Take your evidence and after rubbing your forehead and face with your fingers (to get a good supply of oil), place several fingerprints on your glass and your empty can. Set them into your cardboard box as close to the middle as possible. 

Take your juice glass or small cup and fill it with steaming hot water. 

Once your mug warmer is hot, open one of your Super Glue tubes. Squirt about twenty (20—or 1/3 of the tube contents) drops on your foil square. Be careful not to wrinkle the foil, as a flat section of foil will work best and provide the maximum heat surface. Make sure that the coffee mug warmer is now hot. 

Place the foil square containing the glue onto the hot surface of the warmer. 

Cover the entire box with the section of clear plastic so as to basically seal the box. Make sure that you do not get any moisture from the water on the plastic that you cover the box with. BUT— place one fingerprint or two on the inside of your clear plastic that is covering the top portion of the box as a “control” fingerprint (see below for additional comments on the “control” print). This will allow you to observe your control prints as the fumes spread in the box. 

Now, wait approximately ten minutes (times can vary). You can observe the contents of the box through the clear plastic. The latent fingerprints will begin to turn white as the glue fumes settle on the ridges of the prints. If the “evidence” is left in your Super Glue chamber too long, the prints will “frost” over, and your latent print will be a white smudge with no visible ridge detail. To “check” the progress of your evidence, watch the control fingerprint that you placed on the inside of your plastic covering the box top. As it turns white, you can get a feel for when to remove your evidence. Pull the plastic from the box and remove your evidence—do not inhale the fumes as your eyes will water. Once your evidence is removed, you should see well-stabilized latent print/prints on your processed evidence. 

You may want to repeat this lab several times to get the maximum results, as each time that you repeat it, your results will improve due to your increasing experience.