Indented Paper

If another piece of paper is directly under the piece that is written on, the paper underneath will pick up an impression of the writing. This can be valuable evidence for a detective who is looking for clues in a missing-person case or trying to match the origin of a ransom note in a kidnapping case. Try the following activity to see how this technique is done.

Materials

- several sheets of white paper
- ballpoint pen
- lamp or other light source
- pencil

Procedure

1. Stack the paper. Use the ballpoint pen to write an address or a phone number on the top sheet of paper.
2. Remove the top sheet, then hold the second sheet of paper up to the lamp. Can you see anything?
3. Lay the second sheet flat. Use the edge of the pencil lead to lightly shade over the place where the writing was made. Can you read the address or phone number on the second sheet?

More Fun Stuff to Do

Repeat the experiment, using different types and amounts of paper, and exerting either more or less pressure while writing. Do these changes affect your ability to read the writing on the second sheet of paper?

Explanation

How well the impression can be read will depend on a number of factors, such as the thickness of the paper, whether the sheets were on a hard or a soft surface, and the amount of pressure exerted by the writer.

If an indented sheet is found as evidence at a crime scene, this technique can be used to match it to a threating letter or a ransom note. If a diary or a business ledger with pages torn out is found, this technique can also be used to determine what was written on the missing pages.