Detect Fingerprints

This experiment by detect fingerprintsis a curious experiment, in which iodine adheres to the grease of the fingerprints we may have left behind, thus colouring our fingerprints. A white paper is needed so that they can be seen.

The experiment is simple, although the materials are somewhat specific. Here is the list of materials and the step-by-step of the experiment.

EXPERIMENTAL MATERIALS

• 1 tablespoon copper sulphate - > Find it at Alquera
• 1 tablespoon potassium iodide -> Find it at Alquera

STEP-BY-STEP EXPERIMENT

1. You take a spoonful of potassium iodide and put it in a glass beaker.
2. You take a spoonful of copper sulphate and put it in the same glass.
3. Add a few drops of water to promote mixing.
4. Stir the mixture
5. Place a sheet of white paper where you put your fingers before and place it on top of the glass.
6. Wait 3 minutes and voila! You will have your fingerprints on the glass.

VIDEO EXPERIMENT

Here you can watch the experiment on video

TECHNICAL EXPLANATION

Copper sulphate oxidises the iodide from potassium iodide to iodine. When the paper is placed on top of the glass, some iodine gas is released. Iodine has the ability to stain fat. When you touch the paper, as we always have grease on our hands, some of it stays on the paper, so your fingerprints will be visible.