Chapter 1 Measurements Units of Measurement

Measurement You are making a measurement when you  Check you weight  Read your watch  Take your temperature  Weigh a cantaloupe What kinds of measurements did you make today?

Standards of Measurement When we measure, we use a measuring tool to compare some dimension of an object to a standard.

Stating a Measurement In every measurement there is a  Number followed by a  Unit from measuring device

Learning Check What are some U.S. units that are used to measure each of the following? A. length B. volume C. weight D. temperature

Solution Some possible answers are A. length inch, foot, yard, mile B. volume cup, teaspoon, gallon, pint, C. weight ounce, pound (lb), ton D. temperature  F

Learning Check What is the unit of measurement in each of the following examples? A. The patient’s temperature is 102°F. B. The sack holds 5 lbs of potatoes. C. It is 8 miles from your house to school. D. The bottle holds 2 L of orange soda.

Solution A. °F (degrees Fahrenheit) B. lbs (pounds) C. miles D. L (liters)

Measurement in Science In science we  do experiments  measure quantities  use numbers to report measurements

Metric System (SI) l Is a decimal system based on 10s l Used in most of the world l Used by scientists and many business and organizations

Some Metric System Units length meter m volumeliter L mass gram g temperatureCelsius °C

Learning Check Identify the measurement in metric units. A. John’s height is 1) 1.5 yards2) 6 feet3) 2 meters B. The volume of saline in the IV bottle is 1) 1 liters2) 1 quart3) 2 pints C. The mass of a lemon is 1) 12 ounces 2) 145 grams3) 0.6 lbs

Solution A. John’s height is 3) 2 meters B. The volume of saline in the IV bottle is 1) 1 liter C. The mass of a lemon is 2) 145 grams

Metric System Basics l There is an established standard for each type of measurement l This unit does not have any prefix to it l This unit is then divided by 10s into smaller and smaller divisions l Each of them has the appropriate prefix l Example 1m = 10 smaller units each of which is called a decimeter l So what are the units and the prefixes

Metric Measurement Units l Length = meter (m) l Mass = gram (g) l Volume = liter (L since lower case “L” looks like a one and could be confusing) l Time = second (s) l Force = newton (N) l Pressure = pascal (Pa) l Energy = joule (J) l Electric current = ampere (A)

Mnemonics kangaroos hop down mountains drinking chocolate milk

Kahn’s hot dogs use dead cow meat

1 st Letters Represent the Order of Metric Prefixes k- = kilo- h- = hecto- da- = deka- m/u = meter/unit has no prefix d- = deci- c- = centi- m- = milli-

Subdivisions of the Metric Units When a meter is divided into 10 smaller units, each of them is called a decimeter mathematically 1m = 10dm but since a decimeter is smaller than a meter the portion of a meter that the decimeter represents is one-tenth, or 1dm = 0.1m You need to be able to handle both