An Introduction to Scientific Research Methods in Geography

Montello and Sutton

Chapter 4 - Physical Measurements

Basic tools and techniques for collecting physical measurements

in both physical and human geography.

Learning Objectives

-What are physical models and how are they used in geography?

-What are representative types of physical measurements made by geographers and other scientists who study the four earth systems of the lithosphere, atmosphere, hydrosphere, and biosphere?

- What is geodetic measurement and what are some types?

- What are nonreactive measurements in human geographic research?

- What are the three actions of accretion, deletion, and modification that create physical traces of human activity, and what are the four types of functions of physical traces?

Physical Measurements in Physical Geography

- Before taking any field measurements you must first consider field research logistics. Accessibility, legality, equipment transportation to and from the site (can you bring plant matter through customs?), contingency plans for medical emergencies….

- Physical models: physical or material simulation of a portion of reality.This allows geographers to take measurements removed from the field and with a degree of control - It is nonetheless still a representative simulation.

- Physical materials: samples collected by physical geographers in the field that must be measured, typically in a lab, in order to produce scientific data. (* the word sample will later be used to indicate a set of cases smaller than the entire population of interest)

Physical Measurements in Physical Geography

Geodetic Measurement: measuring spatial properties of the earth and features on it. Typically identified with the earliest origins of geography as an intellectual endeavor.

Geodetic information can express two-dimensional planimetric information and/or three dimensional elevation or altitudinal information.

Tools and techniques of geodetic measurement:

Triangulation - fixing point location by direction, trilateration- fixing point location by distance, theodolites- a tool that measures direction through horizontal and vertical planes, clinometers - measures heights

Physical measurements in Physical Geography

Physical Measurements of Earth Systems

Earth Systems- Lithosphere: having to do with the earth surface crust

- Atmosphere: The enveloped layer of gases and other materials surrounding the terrestrial surface. Of special attention to geographers is the bottom most layer of the atmosphere called the troposphere.

- Hydrosphere: All embodiments of water and its movement through the hydrologic cycle.

- Biosphere: This is all areas of the earth that is home to the living - plants, animals, fungi, microorganisms…

Physical measurements in Physical GeographyExamples:

Each area of study has its own set of tools. Geographers studying elements of soils may use sieve analysis to determine soil texture.

A soil profile can be dug to study the soil horizon.

Rain gauges, thermometers, barometers, and hygrometers all measure conditions, which together help in understanding the weather and the climate.

Physical Measurements in Physical GeographyExamples:

To study climates of the past, proxy measurements must be used.

Proxy measurements are physical measurements that are based on a present trace of past climate conditions.

Tree cores, ice cores and pollen analysis from sediments in ponds can all be used as proxy measurements.

Physical Measurements in Physical GeographyExamples:

Radiocarbon dating is a technique for dating organic materials based on their emission of beta particles from radioactive carbon-14 and it is an important tool for dating soils and some other organic material.

Drifters are a floating object dropped in the ocean and tracked to measure ocean currents.

Physical Measurement in Human Geography

Physical traces refers too the physical evidence of humans in the landscape.

Nonreactive measures such as physical traces are not susceptible to reactance, which is changing behavior as a result of knowing their responses are being measured.

Physical Measurement in Human Geography

The three actions that lead to physical traces:

Accretion - intentional or unintentional addition, deposition, or accumulation.

Deletion - an intentional or unintentional removal, erasure, or obliteration.

Modification - an intentional or unintentional change, alteration, or conversion.

Physical Measurements in Human Geography

Functions of physical traces

1. Byproduct of use

2. Adaptation for use

3. Display of self

4. Public Message