Materials Required:
l Soft-lead pencil, such as a No. 2 pencil
l 2 sheets of paper
l Transparent tape
Your finger
Procedure:
- Hold the pencil on its side and rub the lead on a sheet of paper. Continue rubbing the same spot over and over until it is covered with a heavy black coating.
- Now, press your index finger into the lead spot and move it around. Your fingertip should become thoroughly smeared with pencil lead.
- Press your blackened fingertip onto the sticky side of a small piece of transparent tape. Slowly peel away the tape and stick it onto a clean sheet of paper. You will see an interesting pattern of lines and swirls.
This Is What Happens:
You have just taken your fingerprint. The pencil lead is transferred to your fingertip when you rub your finger in it, then the sticky tape picks up the dark colour from your finger’s ridges. No one else has the same fingerprints as you! Long ago, people would sign their letters by placing a thumbprint on the paper, and about fifty years ago in the United States; people started using fingerprints as a means of identification. And once, a man surveying land in New Mexico used his thumbprint on his reports so that others could not forge his name!
