Читать книгу U Can: Chemistry I For Dummies - Hren Chris - Страница 12

In This Chapter

▶ The SI system, base units, and prefixes

▶ Creating derived units and examining density

▶ How to use conversion factors

▶ Solving with the factor label method

Have you ever been asked for your height in centimeters, your weight in kilograms, or the speed limit in kilometers per hour? These measurements may seem a bit odd to those folks who are used to feet, pounds, and miles per hour, but the truth is that scientists sneer at feet, pounds, and miles. Because scientists around the globe constantly communicate numbers to each other, they prefer a highly systematic, standardized system. The International System of Units, abbreviated SI from the French term Système International, is the unit system of choice in the scientific community.

In this chapter, you find that the SI system offers a very logical and well-organized set of units. Scientists, despite what many of their hairstyles may imply, love logic and order, so SI is their system of choice.

Tip: As you work with SI units, try to develop a good sense for how big or small the various units are. That way, as you’re doing problems, you’ll have a sense for whether your answer is reasonable.