When is zero not significant science?

In scientific measurements, a zero is not considered significant when it serves merely as a placeholder in a whole number, such as in 1200, where the trailing zeros do not indicate precision. Additionally, a zero at the beginning of a decimal, like in 0.0025, is also not significant. However, zeros between non-zero digits, such as in 105, or trailing zeros in a decimal number, like in 2.500, are considered significant. Understanding the context and the placement of zeros is crucial for accurately interpreting the precision of measurements.