Burned Documents

Even a notice that has been completely burned can be important evidence in a investigation. Try the following activity to restore and read a burned document.

Materials

- ballpoint pen
- sheet of white paper
- metal pie pen
- matches (to be used only by an adult)
- cookie sheet
- ½ cup (125 ml) glycerin (available from drufstore)
- 1 ½ cup (375 ml) tap water
- spray bottle
- adult helper

Procedure

Note: This activity requires adult help.
1. Write the message “Robbery set for 3:00 p.m. on Thursday” on the white paper.
2. Crumple the paper into the ball and place it in the middle of the pie pan.
3. Have your adult helper use the matches to set the paper on fire.
4. Allow the fire to burn out and cool down. When the burned paper is cool, carefully transfer it to the cookie sheet.
5. Observe the burned paper. Can you still see any of the writing on the paper?
6. Mix the glycerin with the water and place the mixture in the spray bottle.
7. Carefully spray the burned paper with the mixture until the paper is completely wet. Gently unfold the crumpled paper and flatten it on the cookie set. Use more spray if necessary.
8. Observe the pape. Can you now read any of the writing?

Explanation

A document may be burned either by accident or on purpose. Either way, handling a charred or burned document is one of the most difficult tasks a crime lab can face. The documents must be transferred to the crime lab with the utmost care and are often hand delivered in a cotton – or wool- lined box. Once the document is in the lab, the forensic scientist begins the careful process of reading it.

First, the forensic scientist must flatten the burned document without causing it fall apart. The glycerin – and – water solution used in the activity softened the burned paper so that you could flatten it. Forensic scientists used a similar procedure. They float burned sheets in a large tray containing a mixture of glycerin, alcohol, and a chemical called choral hydrate to soften the paper.

Once the document is flattened, the forensic scientist tries to read it. Most ballpoint pen inks contain a small amount of metal in the dyes. These metals are able to survive fire, so anything written with a ballpoint pen can be seen when the paper is flattened. The forensic scientist then photographs the document as evidence.

If the writing on the document is not easily visible, the forensic scientist will sometimes photograph the burned document with special film called infer red film. This film enhances the writing on the document and helps make it more visible.