Bio 183 Unit 1 Step 3

Measurements and Conversions

For six lab points, do the following lab activity entitled “Measurements and Conversions.” The instructions for this lab are below, but this lab must be done in the Biology Learning Center. There is a worksheet for this activity in your worksheet packet. When you have completed the activity, take the results to the front desk in the Biology Learning Center for lab points.

Equipment and Supplies:

For this lab, you will need Kit #52. In addition, you will need to use the electronic scale (located at the north end of the BLC in the little side room with the refrigerator)

Introduction

Marine science, which includes marine biology, involves investigations of natural objects that range in size from molecular to planetary. From the molecules that make up the ocean to the ocean itself, objects are unique in their size, mass, and volume and yet all are related when it comes to understanding the nature of the ocean and of the Earth.

Almost every scientific investigation requires accurate measurements. One important purpose of this exercise is to examine the metric system as a method of scientific measurement used in marine science.

Measurement
To describe objects, marine scientists use units of measurement that are relative to the particular feature being studied. For example, centimeters or inches, instead of kilometers or miles, would be used to measure the dimensions of a sea shell; and kilometers or miles, rather than centimeters or inches, to measure the width of the Atlantic Ocean.

Most areas of science have developed units of measurement that meet their particular needs. However, regardless of the unit used, all scientific measurements are defined within a broader system so that they may be understood and compared. In science, the fundamental units have been established by the International System of Units (SI; Table 1).

Table 1. Base units of the SI. From these base units, other units are derived to express quantities such as power (watt, W), force (newton, N), energy (joule, J) and pressure (pascal, Pa).

Unit	Quantity measured	Symbol
Meter	length	m
Kilogram	mass	kg
Second	time	s
Kelvin	temperature	K
Ampere	electric current	A
Mole	quantity of a substance	mol
Candela	luminous intensity	cd

The Metric System
The metric system is a decimal system (based on fractions or multiples of ten) that uses only one basic unit for each type of measurement: the meter (m) as the unit of length (Figure 1), the liter (l) as the unit of volume (Figure 2), and the gram (g) as the unit of mass (Figure 3). In the English system the units used to express the same relations are feet, quarts, and ounces.

Figure 1. The SI unit of length is the meter (m), which is slightly longer than a yard. Originally described a one ten-millionth of the distance from the equator to the North Pole, it is currently defined as the distance traveled by light in a vacuum in 0.0000000033 of a second.

Figure 2. The basic unit of volume in the metric system is the liter (l), equal to the volume of one kilogram of pure water at 4°C (39.2°F). A liter is 1.06 quarts.

Figure 3. The basic unit of mass in the metric system is the gram (g), approximately equal to the mass of one cubic centimeter of pure water at 4°C (39.2°F). A gram is about the weight of two paper clips; an ounce is about the weight of 40 paper clips.

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