Have you ever sneaked into the kitchen to grab a cookie without anyone noticing? If you didn’t wear gloves, you probably left behind evidence of your snack. A fingerprint expert could potentially find your fingerprints on the cookie jar and match them to the unique prints on your fingers.

Fortunately, most parents are not experts in fingerprint analysis or crime scene investigation (CSI). However, the cookie crumbs on your face might still give you away!

Take a close look at your palms and fingertips. Do you see the tiny ridges and lines? If you pressed your finger onto an inkpad and then onto a piece of paper, it would leave a print of the lines and ridges on your finger — a fingerprint!

Your fingerprints are special. This means that no one else in the world has the exact same set of ridges and lines as you do on your fingers. Even identical twins have different fingerprints.

Your fingerprints also remain the same from birth until death. Their uniqueness and permanence make fingerprints one of the most reliable ways to identify a person.

Did you know that you don’t need to dip your fingers in ink to leave fingerprints? Sweat and body oils are continuously secreted through tiny pores in our skin. These substances cover the ridges and lines on your fingers.

When you touch something, you transfer these substances, leaving an impression of the ridges and lines on your fingers. These fingerprints — known as latent fingerprints — are usually invisible to the naked eye. However, you can sometimes see them on certain objects, such as a glass bottle.

Scientists have been aware of these invisible fingerprints since the 19th century. As early as 1892, English scientist Sir Francis Galton wrote a book about using fingerprints to solve crimes. However, it was not until 1896 that Sir Edward Richard Henry developed a way to classify fingerprints based on their general ridge patterns: loops, whorls, and arches.

Henry’s system of fingerprint identification, called dactyloscopy, has been slightly modified over time. Today, it is still utilized by law enforcement agencies worldwide.

Over the last century, advancements in technology have aided law enforcement officers in making better use of fingerprints. Nowadays, fingerprints can be “lifted” — identified and copied for later comparison — from almost any surface using special fingerprint powder.

In addition, scientists no longer require complete fingerprints. With the help of advanced computers and software, even half a fingerprint can be identified and matched with a comparison sample. Computers can even automatically make comparisons, although final verification of a fingerprint match is still performed by scientists who carefully examine and compare the fingerprints to ensure an accurate match is found.

However, fingerprints are not the only method scientists use to identify individuals. There are various types of biological and behavioral characteristics, known as biometrics, that can be used for identification. Other examples of biometrics include DNA, iris patterns, voice patterns, and facial patterns.

Give It a Try

Are you interested in exploring fingerprints further? Make sure to try out the following activities with a friend or family member:

Fingerprint Fun!

Ever wondered how your fingerprints look? Well, here’s a fun activity for you to try! All you need is a pencil, a piece of paper, and some clear tape. Just follow the instructions for the Fingerprints activity online and you’ll get to see your unique fingerprint. You can even find out if it’s a whorl, a loop, or an arch and compare it with others!

If you’re feeling creative, you can also turn your fingerprints into amazing works of art that your parents will love. Give these fun activities a try: Fingerprint Penguin, Fingerprint Turkey, Fingerprint Whale, and Thumbprint Art.

Are you interested in becoming a crime scene technician? Well, one of the important skills you’ll need is the ability to find, preserve, and analyze fingerprints. You can start practicing today with the Dusting for Fingerprints Science Experiment. Just go online and give it a try. Remember to ask an adult for help and gather the necessary supplies.

Wonder Sources

• http://www.fbi.gov/about-us/cjis/fingerprints_biometrics
• http://www.childidprogram.com/the-id-kit/facts-about-fingerprints
• https://www.britannica.com/topic/dactyloscopy

FAQ

1. Why are fingerprints unique to each individual?

Fingerprints are unique to each individual because they are formed by the ridges and patterns on the skin of our fingers. These ridges are formed during fetal development and remain unchanged throughout our lifetime. The unique combination of loops, arches, and whorls in our fingerprints is determined by both genetic and environmental factors. Even identical twins have different fingerprints. This uniqueness makes fingerprints a reliable method of identification in forensic science.

2. How do fingerprints help in solving crimes?

Fingerprints are crucial in solving crimes because they can be found at the scene of a crime and can be used to identify individuals involved. When a person touches a surface, they leave behind a trace of sweat, oil, and other substances from their skin, creating a fingerprint. Forensic experts can collect these fingerprints and compare them to a database of known fingerprints to identify suspects. Fingerprints are considered a reliable form of evidence because they are unique to each individual and do not change over time.

3. Can fingerprints be altered or disguised?

Fingerprints cannot be altered or disguised permanently. While it is possible to temporarily alter fingerprints with substances like glue, tape, or chemicals, these alterations are usually detectable by forensic experts. Additionally, the ridges and patterns in our fingerprints are determined by our genetic makeup, which cannot be changed. Even surgeries or injuries to the fingertips do not alter the underlying ridge structure. This is why fingerprints remain a reliable method of identification in forensic science.

4. Are fingerprints used for purposes other than identification?

Yes, fingerprints are used for purposes other than identification. They can be used for access control, such as unlocking smartphones or entering secure areas. Fingerprints are also used in banking and financial systems for authentication. In some countries, fingerprints are used for voter registration to prevent fraud. Additionally, fingerprints can be used in medical research to study genetic traits and identify potential health risks. The unique nature of fingerprints makes them a versatile tool in various fields beyond law enforcement.