demonstrations:detecting_fake_blood_with_luminol
Detecting Fake Blood with Luminol
Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★☆ Some safety precautions required to perform safely
Categories: Catalysts, Forensics
Alternative titles: Luminol Detection of Blood-Meal Stains
Summary
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.
Procedure
- Mix blood meal with a little water and apply as fake blood stains on a surface; let dry slightly.
- Prepare a luminol solution with sodium hydroxide and hydrogen peroxide.
- Darken the room and spray or drip the luminol solution onto the stains.
- Observe the blue glow and compare it to an unstained control area.
- Record or photograph results before the glow fades.
Links
Luminol Experiments, Blood Detection, Fake Crime Scene Cleanup - sdriza:
Variations
- Purchase a commercially available luminol kit.
- Test different amounts of blood meal.
- Compare glow on porous vs. nonporous surfaces.
Safety Precautions
- Wear gloves and goggles.
- Use only dilute sodium hydroxide and 3% hydrogen peroxide.
- Do not mix luminol with bleach or ammonia.
- Handle blood meal carefully; avoid dust and wash hands afterward.
Questions to Consider
- Why does blood meal make luminol glow? (It contains iron, which catalyzes the reaction.)
- How does stain size or freshness affect the glow?
- What other everyday substances might cause false positives?