Have you ever tip-toed into the kitchen to sneak a cookie out of the jar when no one was looking? Unless you wore gloves, you probably left behind evidence of your snack attack. A fingerprint expert could likely find fingerprints on the cookie jar and match them to the unique prints at the end of your fingers.

Luckily, most parents are neither fingerprint experts nor crime scene investigators (CSIs). However, the cookie crumbs on your chin might still give you away!

Take a close look at your palms and the tips of your fingers. Do you see the tiny ridges and lines? If you pressed a 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 unique. That means that no one else in the world has the exact same set of ridges and lines that you have on your fingers. Not even identical twins have the same fingerprints.

Your fingerprints also stay the same from the time you’re born until death. Their uniqueness and lasting quality make fingerprints one of the best ways to identify a person.

Did you realize that you don’t have to dip your fingers in ink to leave fingerprints? Sweat and body oils are constantly pushed out through tiny pores in our skin. These substances coat the ridges and lines of your fingers.

When you touch something, you transfer these substances to whatever you touch, leaving an impression of the ridges and lines on your fingers. These fingerprints — called latent fingerprints — usually can’t be seen by the naked eye. However, you can sometimes see them on certain objects, such as a glass bottle.

Scientists have known about 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. It was not until 1896, however, that Sir Edward Richard Henry would develop a way to classify fingerprints based upon their general ridge patterns: loops, whorls and arches.

Henry’s system of fingerprint identification — called dactyloscopy — has been modified slightly over time. Today, it is still used by law enforcement agencies all over the world.

Over the last 100 years, advances in technology have helped law enforcement officers make even better use of fingerprints. Today, fingerprints can be “lifted” — identified and copied for later comparison — from just about any surface using special fingerprint powder.

Moreover, scientists don’t even need complete fingerprints any more. With the help of advanced computers and software, even half a fingerprint can be identified and matched with a comparison sample. Computers can even be used to make comparisons automatically, although final verification of a fingerprint match is still done by scientists who carefully study and compare the fingerprints to ensure a proper match is found.

Fingerprints aren’t the only thing scientists use to identify people, though. There are several different types of biological and behavioral characteristics — called biometrics — that can be used to identify an individual. Other examples of biometrics include DNA, the irises of the eyes, voice patterns and facial patterns.


54 Join the Discussion

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    • Hi, Rahul! You’re the first comment today! Thanks for always being such a GREAT Wonder Friend and for letting us know something you learned by exploring the Wonder of the Day®! :-)

  1. We have to write three facts each day. He are my three facts: no one else in the world has the exact same set of ridges and lines that you have on your fingers. Not even identical twins have the same fingerprints. You don’t have to dip your finger in ink to leave a fingerprint. Those are my three facts.

  2. Hey wonderopolis. This wonder was really cool. My fingers have a lot of lines. I noticed when I touch a window, my finger prints stay on the window.

    • That’s really cool how you observed your fingerprints staying on the window after you touched it, Dominque! Thank you for adding something super special to this Wonder by sharing your personal experience and what your own fingerprints look like! :-)

  3. We think this is a great idea! We spend a lot of our lunch time putting our numbers into the machine. We think our school should try this out too! This way we won’t have to memorize our numbers!
    Our question: Do all fingers on the same hand have the same fingerprint?

    • We’re really glad you guys visited Wonderopolis today and learned all about fingerprints, Mrs. Shoemaker’s Class! It was AWESOME to get a comment from you today! Every fingerprint on every finger, whether on the same hand or not, are different. Even if you look closely at your fingers and think you see two fingers with the same print, they are different! It’s really cool to think about that, isn’t it? Your fingerprints only belong to you, and everyone of your fingers has its own special fingerprint! :-)

    • Hello, Michelle! We learned a lot about fingerprints by exploring this Wonder, too! Thank you for leaving us a comment to let us know you visited Wonderopolis today! :-)

    • Greetings from Wonderopolis, Room 20! It makes us super happy to hear that you had FUN visiting this Wonder of the Day®! We appreciate your comment! :-)

  4. We think that it is interesting how everything we touch we leave a fingerprint. We liked the video and thought it was cool how the students only pushed their fingertip on the machine to leave a print or for the print to be scanned. Thanks a lot Wonderopolis!

    • Thank YOU for letting us know that you liked the video for this Wonder and that you learned some cool new facts about fingerprints, North Todd Elementary School 3rd grade writers! We think you guys ROCK! :-)

  5. I think it was cool. I made a fingerprint myself. We used pencil lead rubbed on our fingertips and put them on paper.

    • That sounds like a super fun way to learn what your own fingerprints look like, Miguel! Thanks so much for sharing how you did it…now maybe some other Wonder Friends will try rubbing their fingertips with a pencil and pressing their fingerprints on paper, too! Way to go! :-)

  6. I think it will be faster if you put your finger in a finger scanner, so it won’t take long. I wish we had that at our school.

    • Scanning fingertips instead of punching in numbers sure seems like it would make life in the lunch line a lot easier, Jimmy! We agree! Thank you for sharing your thoughts about today’s Wonder! :-)

  7. THE VIDEO WAS COOL!!!!!!!

    • You’re certainly welcome, Kymberly! Thank YOU for leaving us this cool comment and for hanging out in Wonderopolis today! :-)

  8. Thank you for the interesting Wonder! We made thumbprint art and then looked at our fingerprints under a magnifying glass. We looked up more fingerprint patterns. We discovered that most of our class has the loop pattern and only a couple of students have the pocket pattern. We wonder if the loop pattern is more common.

    • We LOVE the extra WONDERing you guys did after you explored this Wonder about fingerprints, The Beach! We also think it’s really interesting to learn that the majority of your class has the loop pattern! We did a little extra WONDERing of our own after we received your comment, and found that loop patterns are prevalent in 60% – 70% of all fingerprints! We’d say that’s a pretty popular print! :-)

    • Thank you for trying to guess tomorrow’s Wonder topic from the “Wonder what’s next?” clue, Rebecca! YOU ROCK! Let’s ALL meet back here in Wonderopolis tomorrow to see if your guess was right, OK? :-)

  9. Dear Wonderopolis,
    Everyone’s fingerprints are different. That is one of the things that make them unique. I think there are 3 main types of fingerprints, an arch, loop, and a swirl. I also think it’s cool that we can be identified by our fingerprints. Thank you for being awesome wonderopolis! XOXOXOXOXO,
    Paige ;)

    • We think you’re pretty awesome yourself, Paige! We appreciate all your FANTASTIC comments and enjoy hearing about all the things you learn about when you visit Wonderopolis. Keep up your awesomeness, OK? :-)

  10. Every day in my home room, we have to write three facts. Here are mine, did you know that know no one in the whole world has the same fingerprint as you or me, not even identical twins have the same fingerprint. Last year my teacher Mrs. Martin had us dip are finger into ink so we could find out what are fingerprint is. I have different kinds of fingerprints. I thought it was pretty cool. You should try it out sometime. Well, thanks wonderopolis for being here for our questions to answer… Sincerely, Macy

    • We will have to try the inky fingerprint activity, Macy! Thanks so much for sharing it with us and for visiting Wonderopolis today! :-)

  11. The video was interesting. My fingerprints are all loops. I think finger painting is fun. Finger painting on paper looks fun, too.

    • Happy Thursday, Shelby! Thank you so much for leaving us this great comment and for sharing your thoughts on finger painting. It really IS a lot of fun, we agree! :-)

    • Happy Tuesday, Kassidy! We’re glad you learned some cool new facts about fingerprints by exploring this Wonder of the Day® about them! Way to go! :-)

  12. Question: do your two thumbs have the same print, because when I was looking at my two thumbs, they looked exactly the same.
    I’m actually doing a science project on Forensics. Fact: Some of the most common patterns are the arch, the whorl, and the loop. My thumbs are loops, and my other fingers are all whorls.

    • Thanks for sharing about your own fingerprints, Alice! Even though your thumbprints might look super similar, they’re each quite unique! Isn’t that a cool fact? We think it’s really neat that you are doing a project on forensics! :-)

  13. Wonderopolis is a interesting website. I learned how our fingerprints are different than others, and that no one else has the same fingerprints as you do. They may look the same a little bit, but they aren’t the exact same print. :)

    • WOW! You sure learned a lot about fingerprints by exploring this Wonder, Amondria, and we think that’s SUPER! Thanks for letting us know what you learned! :-)

  14. I’ve learned today that everybody’s fingerprints are different and that we are all unique in every way !!!!!!!!!!!!!!!!!

    • You’re RIGHT, Tiara! We are all unique and AWESOME! Thanks for visiting this Wonder today and leaving us another great comment! :-)

  15. I’m doing a science fair project and my question is what surface temperature of a glass will you be able to see a fingerprint the best. I have a 2 page background research paper due in 3 days this website has really helped me get a lot of info for my paper thank you Wonderopolis.

    • We’re so glad this Wonder helped you with your project, Hrishika! We Wonder what your project was for… a class assignment, a science fair? :)

  16. I have been using all of my facts off of here to get an A+ on my 5th grade science fair and thanks to you guys I got a 100% A+


    • We’re so happy to hear that we’ve been able to help you learn and Wonder, Summer! Nice work! You should be very proud of yourself! We’re sending you a virtual high five! :)

  17. Wonder Wednesdays! Just came back from Disney World have so many wonders about that place and my birthday is on Saturday yay!!!!!!!

  18. No they are not because fingerprints help you more and you can get through it everything easily but fingerprinting it can take you forever, even scientists had used fingerprints before and some of them still do to help them get through things fast and easily….and right on wonderopolis all different kind of people are talking about how good it is to have a fingerprint at their school because they get through their lunch quick and fast no one had to starve or anything like that, that’s why in my opinion I think fingerprints are more useful than fingerprinting.

    • Hi Amina, you’ve done a WONDERful job explaining the pros and cons of fingerprinting! Nice work, Wonder Friend!

      We think you have an awesome imagination and are full of ideas – we bet you will invent a super cool fingerprinting system in the future! Keep up the great work! :)

  19. I think this is good because kids can now have more time to eat & kids now don’t have to take a card or ID to cafeteria only their finger

    • Nice job, Henry, we think you did a great job sharing your idea and comment! We think it’s pretty cool that you can be identified only using your unique fingerprints! It’s so fun to Wonder! :)

    • That’s right, Madalyn! We are all as unique as our fingerprints! Thanks for WONDERing with us today, Wonder Friend! :-)

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Have you ever wondered…

  • What’s so special about your fingerprints?
  • Do identical twins have identical fingerprints?
  • What is dactyloscopy?

Wonder Gallery

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Try It Out

Ready to see what your fingerprints look like? Grab a pencil, a piece of paper and some clear tape. Follow the instructions for the Fingerprints activity online. You can even determine whether your fingerprint is a whorl, a loop or an arch and submit your information to compare with others!

If you want to turn your fingerprints into a unique piece of art that your parents will treasure, try one of these fun activities:


Still Wondering

Using ReadWriteThink’s Mystery Cube Tool Tip Sheet, children will separate a mystery into its distinct elements, like ingredients in a recipe. By listing the elements — one on each side of a cube — children will begin to see how a writer constructs a mystery. Maybe fingerprints were left at the scene of the crime!


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