Try This: Fingerprinting The first known use of fingerprints is the ancient Chinese custom of signing legal documents. However, fingerprints weren't actually classified until the 19th century. In 1892, Sir Francis Galton, a British scientist (and Charles Darwin's cousin), published a book that classified all fingerprints into three basic types: loops, arches and whorls (see below).
Over the years, law enforcement authorities have studied millions and millions of fingerprints. In fact, the FBI adds about 7,000 new fingerprints to its computerized database each day!
Out of all fingerprints:
- 60 - 65 percent of are classified as loops.
- 30 - 35 are classified as whorls.
- 5 percent are classified as arches.
Let's try an experiment to see how the fingerprints from your classmates compare to the overall population. Have each person make their own fingerprint sheet, following these simple instructions:
- With a standard no. 2 pencil, draw a box about two inches high and one inch wide on a white sheet of paper.
- Fill in the box with the pencil, making sure to keep it dark and even. We'll use this box like the police use their ink pad to take fingerprints.
- Beginning with your index finger, gently rub the pad of each of your fingertips over the penciled-in rectangle, being careful not to rub it too hard (it smudges if you rub it too hard). Now, take a piece of clear tape and press it on your fingertip. Lift the fingerprint off and apply the tape to a piece of white paper. Mark what finger it came from. Repeat the step for each finger. Now you have a complete set of fingerprints!
- Finally, determine if you have a loop, whorl or arch by comparing it to the samples below.
Total up all of the results for your class and convert your data into percentages (loops, whorls and arches). Graph your results on a chart and compare your results with the overall population. How does your class compare with the national average?
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