Lecture Notes: Metric and Imperial Systems

Introduction

• Discussion on the superiority between Metric and Imperial systems.
• The Metric system is used worldwide, while the Imperial system is primarily used in the United States.

Arguments for the Imperial System

• Imperial system: uses arbitrary units like feet and yards.
• It's suggested that the Imperial system is tied to American freedom and individuality.
• Concerns about scientists trying to impose the Metric system globally.

Overview of the Metric System

• Known for its use of numbers and prefixes for measurement.
• Base 10 system: easier conversion and standardization.
• Common prefixes:
  • Kilo-: Multiplies the base unit by 1,000 (e.g., kilometer).
  • Centi-: Divides the base unit by 100 (e.g., centimeter).
  • Milli-: Divides the base unit by 1,000 (e.g., millimeter).

SI System (Systeme International)

• A derivative of the Metric system used by scientists.
• Utilizes the same base 10 principle.
• Prefixes represent powers of 10 and remain consistent across measurements (length, volume, mass, energy).

Importance of Memorizing Prefixes

• Memorization is crucial for efficiency, especially in exams and scientific work.
• Prefixes are essential for unit conversions, which are frequent in science.

Base Units in SI and Metric Systems

• Length: Meter (used in both systems).
• Time: Seconds (used in both systems).
• Mass:
  • SI: Kilogram.
  • Metric: Gram.
• Temperature:
  • SI: Kelvin.
  • Metric: Celsius.
• Volume:
  • SI: Cubic meter.
  • Metric: Liter.
• Energy:
  • SI: Joule (derived from kilograms).
  • Metric: Calorie (specific to raising temperature of water).

Calorie vs. Kilocalorie

• Food packaging often uses capital C to indicate kilocalories (1 kilocalorie = 1,000 calories).
• Important for those in health care: conversion between joules and calories.

Conversion between Joules and Calories

• 1 calorie = 4.184 joules.
• Memorization of this conversion is necessary for scientific calculations.

Conclusion

• Understanding these systems and conversions is fundamental for science and everyday applications.