Overview
This lecture introduces metric prefixes, explains their use with base units, and outlines a method for converting measurements between different metric prefixes using exponents.
Metric Prefixes and Base Units
- Metric prefixes represent powers of ten and are used with base units such as grams, meters, and liters.
- Each prefix is a shorthand for a specific amount of a base unit (e.g., 1 kilogram = 1,000 grams).
- The abbreviation combines the prefix symbol and the base unit symbol (e.g., kg for kilogram, cm for centimeter).
- Any quantity can use prefixes (e.g., 8 milliliters = 8 mL).
Using the Metric Prefix Chart
- The chart lists prefix names, their symbols, and their exponents of ten.
- Base units (meter, gram, liter) have an exponent of 0 (10^0).
Converting Between Prefixes
- To convert units, subtract the exponent of the starting prefix from the exponent of the target prefix.
- Move the decimal point in the number by the difference in exponents.
- Right if moving to a smaller unit; left if moving to a larger unit.
- Fill blank decimal places with zeros as needed.
Sample Conversions
- 0.150 meters to centimeters: 0 - (-2) = 2; move decimal 2 places right → 15.0 cm.
- 0.150 kilometers to centimeters: 3 - (-2) = 5; move decimal 5 places right → 15,000 cm.
- 384.0 milligrams to decigrams: (-1) - (-3) = 2; move decimal 2 places left → 3.84 dg.
- 1 liter to megaliters: 0 - 6 = -6; move decimal 6 places left → 0.000001 ML.
Key Terms & Definitions
- Metric Prefix — Symbol attached to a base unit indicating a power of ten (e.g., kilo-, centi-, milli-).
- Base Unit — The fundamental unit without any prefix (e.g., meter, gram, liter).
- Exponent — The power of ten the prefix represents (e.g., kilo = 10^3).
Action Items / Next Steps
- Review and use the provided metric prefix chart for conversions.
- Practice converting between different metric units using the subtraction of exponents method.