The new way to uncover adulterated goods - Identify liquid by analysis the knocking sound

If you knock on 2 bottles of different liquids, you’ll hear different sounds. We designed a device that can accurately identifies 2 liquids with the differences of the sounds. At last, we can use our device to identify the fake gasoline which is mixed with other cheap solvent. Furthermore, we can identify which kind of liquor is in the glass bottle without opening it.