When people touch an object, the oil on the fingertips and dried sweat will be left on the object, and the palms and toes will also leave identifiable marks when they touch the object

Everyone's fingerprints are different, and a fingerprint pattern is formed by the lines on the fingertips. Fingerprints have different texture characteristics

Great tool set to cultivate children's observation, logic, reasoning ability, and cultivate children's scientific exploration spirit