Measurements

Concepts to Explore

Units and unit conversion

Accuracy vs. precision

Scientific notation

Significant digits

Calculation accuracy

The foundation of science rests on the ability to perform specific mathematical functions as well as an understanding of important factors of measurement. It is necessary to understand the basics of units and how to convert between them (e.g. 1 minute = 60 seconds).

Unit Conversion:

Often times, you may have to make several unit conversions before arriving at the appropriate units for that measurement. For example, if you knew it took you 3450 seconds to drive from your house to the post office, determining the number of minutes it would take involves converting units.

Converting seconds to minutes:

Conversion Chart

Temperature: °C = 5/9 (°F - 32)

Time: 60 seconds equals one minute, 60 minutes equals one hour

Mass: 1000 milligrams equals one gram, 1000 grams equals one kilogram

Length: 2.54 cm equal one inch

Another important concept in science is understanding the difference between accuracy and precision. Accuracy describes the proximity of a measurement to the norm or standard. Take, for example, a target with a bulls-eye in the middle. The closer you shoot to the bulls-eye, the greater the accuracy.

Precision, another important description of measurement in science, differs from accuracy in that it determines how closely related the variables are. Using the target analogy, the arrows would all need to be very close to one another. When talking about precision, hitting the bulls-eye is less important than getting all your arrows to hit the same area of the target.

When both accuracy and precision are present, a result typically is considered valid. It is important to remember, though, that an object can be accurate without being precise and vice-versa.

Significant Digits:

The number of digits in a number reflect its precision. Significant digits are the digits in...