The document discusses scientific notation and significant figures, which are important concepts in physics. It defines scientific notation as representing a number as the product of a mantissa between 1 and 10 and an exponent of 10. Significant figures refer to the reliable digits in a measurement. The document also introduces the International System of Units (SI) which standardizes scientific units worldwide and defines the base units of the meter, kilogram, and second. Derived units like joules, ohms, and pascals are also defined in terms of the base units.