Forensics Demonstrations

Forensics activities show how scientific methods are used to solve crimes, from analyzing substances to comparing evidence. They are popular because they combine real-world problem solving with dramatic, investigative scenarios.

Demonstration	Materials	Difficulty	Safety	Summary
Pen Ink Chromatography	★☆☆	★☆☆	★☆☆	Use simple paper chromatography to separate the color components in fountain pen inks. A small ink line on chromatography paper or paper towel is developed with water so the dissolved dyes travel different distances and reveal hidden color blends.
Collect and Observe Fingerprints	★☆☆	★☆☆	★☆☆	This simple experiment allows students to collect and observe their unique fingerprints using only pencil lead, tape, and paper. It highlights the individuality of fingerprints and how they can be used for identification.
DNA Extraction From Kiwi Fruit	★★☆	★★☆	★☆☆	This experiment demonstrates how DNA can be extracted from fruit cells, such as from kiwi fruit. The DNA becomes visible as strands at the boundary between the fruit extract and chilled ethanol.
Simulated Blood Typing	★★★	★☆☆	★☆☆	Students use a simulated blood typing kit to identify the ABO and Rh blood groups of synthetic blood samples. The activity demonstrates how agglutination reactions work in real blood typing while remaining completely safe.
Shoeprint Identification	★★☆	★☆☆	★☆☆	Students take on the role of detectives to analyze shoeprints found at a crime scene and compare them to suspect prints. By examining features such as size, tread patterns, and wear marks, they determine which suspect’s shoe matches the evidence.
Soil Analysis	★★☆	★☆☆	★☆☆	Students investigate a “cold case” by analyzing soil samples from suspects and a crime scene. Using observations of color, texture, structure, and pH, they determine which suspect’s soil matches the evidence.
Blood Spatter Patterns	★★☆	★☆☆	★★☆	Students design and conduct an experiment using fake blood to investigate how drop height affects the diameter and features of a bloodstain. By testing multiple heights (including those that approach terminal velocity), students observe trends in stain size and spatter patterns.
Tool Mark Identification	★★☆	★☆☆	★☆☆	Students create and examine tool marks in clay to learn how forensic scientists compare impressions and striations made by tools at crime scenes. By comparing known samples with unknown marks, they practice making positive identifications and ruling out mismatches.
Bite Mark Analysis	★★☆	★☆☆	★☆☆	Students create and analyze bite impressions to compare with a photographic bite mark from a crime scene. By measuring distances between teeth and looking for unique dental features, they determine which suspect’s bite could have caused the injury.
Hair Sample Analysis	★☆☆	★☆☆	★☆☆	Students act as forensic scientists by examining hair samples collected from suspects and a crime scene. Using magnifying tools, they compare features such as color, thickness, and curliness to identify the most likely suspect.
Handwriting Analysis	★☆☆	★☆☆	★☆☆	Students act as forensic handwriting analysts by comparing a note from a crime scene to suspect handwriting samples. They examine features such as form, line quality, spacing, and grammar to determine the most likely match.
Forensic Fiber Analysis	★★☆	★☆☆	★☆☆	Forensic scientists analyze fibers from crime scenes using tests such as burn analysis and polarized light microscopy. These methods reveal whether a fiber is natural or synthetic and help investigators narrow down suspects without destroying evidence.
Strawberry DNA Extraction	★★☆	★★☆	★★☆	By crushing strawberries and treating them with detergent, salt, and alcohol, students can extract visible strands of DNA. The detergent breaks open the cells, salt keeps proteins separate, and alcohol causes DNA to clump so it can be seen with the naked eye.
Detecting Fake Blood with Luminol	★★★	★★☆	★★☆	A luminol solution (luminol + sodium hydroxide + hydrogen peroxide) can be used to reveal “fake” blood stains made from blood meal fertilizer. The demo compares a control surface to areas stained with a blood-meal slurry and documents the chemiluminescent glow in the dark.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff