Measurement, Units and Precision
Engineering is the art of building things that work and fit together. But a bolt made in Bishkek only fits a nut made in Osh if both people agree, exactly, on what "10 millimetres" means. Measurement is the shared language that lets thousands of people who never met build one machine that works.
In this lesson you will learn the units engineers use every single day, how to convert between them without mistakes, the difference between being precise and being accurate, the tools that do the measuring, and why every real part comes with a small allowed error called a tolerance. By the end you will think about numbers the way an engineer does.
Your learning goals
- Explain why a common system of units is the backbone of all engineering.
- Name the SI base units (metre, kilogram, second, ampere, kelvin) and the key derived units (newton, pascal, watt, joule, volt), and have a "feel" for their size.
- Use metric prefixes (milli, centi, kilo, mega) and convert between them.
- Convert any unit safely with the multiply-by-one method.
- Tell the difference between precision and accuracy, and read significant figures.
- Recognise common measuring tools and their typical precision.
- Understand tolerance and why tighter tolerance costs more money.
- Use estimation to sanity-check whether an answer is even possible.