Case of the missing cookies (forensic activity)

Students carry out a series of activities involving simple chemical tests, chromatography, microscope use and fingerprint analysis to determine who stole the cookies.
Pages 1 to 4 can be printed back to back and laminated for re use.
Page 1: outlines the activity and flowchart for chemical tests
Page 2: examples of types of fibres and their features
Page 3: examples of eight types of fingerprints
Page 4: chromatography instructions - methylated spirits can be replaced with ethanol or another solvent depending on the type of pens used.
Page 5: template for “suspect fingerprints”. Print and laminate copies for groups, and print one set and cut them up to use as “prints from the scene”
Page 6: evidence and analysis sheet. Students record the information from their analysis of each piece of evidence - they can use sticky tape to stick in some fibres, their chromatography strip and a suspect fingerprint

Put together sets of evidence from the scene for student teams to collect for testing:
containers with fibres and white powder, photocopies of a few fingerprints from the “scene”
Any pens will need to to be set up so that all students can come and use them to prepare their chromatography strip.

A chromatograph of the pen that wrote the note and the “piece” that was found in a plastic bag (taped to bench or window/wall somewhere). Not to be removed students have to come and look at it to check.

If more groups are involved this can easily be adapted to change which suspect is guilty.