Press your fingertips on a clean drinking glass to create a set of fingerprints. Sprinkle cornstarch on the fingerprints and use a soft-hair make-up brush to gently clean off the extra powder. Firmly press a piece of transparent tape over the dusted prints, and put the tape on a clean index card. You should have a good set of fingerprints.
Make a homemade ink pad by rubbing a thick layer of pencil lead on a small area of an index card. Keep rubbing the pencil on the paper until the card has a shiny appearance.
Roll your fingertip on your homemade ink pad. Rub your finger until it is thoroughly coated in pencil lead. Press a piece of transparent tape on your fingertip, and transfer the print by firmly pressing the tape on another clean index card. Compare this print to the one you took off the drinking glass.
Make this activity more challenging by having several family members leave their prints on different drinking glasses. Lift as many different prints as possible and try to match each print with the person who left it.