Latent Forensic Fingerprint Dusting & Ridge Analysis

45 mins Ages 7-9 Indoor

An engaging, screen-free learning activity that builds real-world creativity and critical thinking for kids aged 7 to 9.

Materials Needed

  • • Unsweetened cocoa powder or fine pencil graphite scrapings (1 tablespoon)
  • • Ultra-soft blush makeup brush or camel hair brush (1 unit)
  • • Clear adhesive tape (2 inches wide) (1 roll)
  • • White and black index cards (4 cards)
  • • Magnifying glass (1 unit)
  • • Clean glass cup (1 unit)

Pro Tips

  • → Have your child rub their index finger on their forehead or nose to pick up sebaceous skin oils before touching the clean glass.
  • → Use an exceptionally light, circular swirling motion with the brush tip; pressing hard wipes the ridge lines away.
  • → Transfer the lifted tape onto dark paper for cocoa powder, or white paper for dark graphite.

Safety First

Do not inhale fine cocoa or graphite dust; work gently with the dusting brush.

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Step-by-Step Instructions

1

Step 1

Press an oily index finger firmly against the side of a clean, smooth glass tumbler.

2

Step 2

Dip the tip of a very soft makeup brush into cocoa powder, tap off the excess, and gently swirl it across the glass surface.

3

Step 3

Carefully press a strip of clear packing tape over the revealed ridge pattern, smooth it down, and peel it off to lift the print.

4

Step 4

Mount the tape onto cardstock and use a magnifying glass to classify the ridge structure as a loop, whorl, or arch.

What they are learning

Dactyloscopy fingerprint patterns (loops, whorls, arches) Sebaceous oil adhesion physics Forensic chain-of-custody transfer