Museum of Science and Industry

Identify Your Fingerprints

Step 1 of 9:

Here's the Materials You'll Need:

Non-toxic ink pad
Light-colored balloon (you also can use paper)
Magnifying glass (optional)

Step 2 of 9:

Roll your finger from side to side in the ink pad.

Step 3 of 9:

Press your finger, flatly and firmly, on the deflated balloon. Lift your finger off without smudging the ink.

Step 4 of 9:

Blow up the balloon.

Step 5 of 9:

Examine the ridges of your fingerprint, which has expanded on the balloon. You can use a magnifying glass to get a better look. Compare your fingerprint to the examples in the next steps to see if you have a loop, whorl, or arch.

Step 6 of 9:

The loop is the most common type of fingerprint. The ridges form elongated loops. Some people have double loop fingerprints, where the ridges make a curvy S shape.

Step 7 of 9:

In a whorl fingerprint, the ridges form a circular pattern.

Step 8 of 9:

Arch fingerprints have ridges that form a hill. Some arches look like they have a pointed tent shape. Arches are the least common type of fingerprint.

Step 9 of 9:

Make prints for all your fingers. Do you have the same type of fingerprints on each finger? Are any of your fingerprints hard to identify? Visit the FBI website (www.fbi.gov/kids/k5th/whatwedo3.htm) for more photos to help identify your fingerprints.