HONORS EARTH / ENVIRONMENTAL SCIENCE

MS. REATHAFORD

THE NATURE OF SCIENCE

Chapter 1

Science

Science is the process of observing and studying things in our world.

Science can be applied to almost anything and is divided into four general areas: 1. Chemistry 2. Physics 3. Life Science (Biology, Anatomy, etc) 4. Earth Science

* Note that you MUST take 3 of these to graduate HS! *

Earth Science

Earth Science is the study of Earth and space. Within Earth Science, there are four major divisions:

1. Astronomy2. Meteorology3. Geology4. Oceanography

The systematic study of our environment and our proper place in it

Draws on many disciplines, skills and interestsIntegrates natural sciences and social sciencesIntegrates humanities in a broad, holistic study of the world around us

Persistent challenges to face, most of which we have created

Pollution Population GrowthClimate Change Biodiversity Loss

Improvement in many areas that benefit our planetEducation Health CareWater Quality Energy alternatives

Environmental Science

Most scientists believe that Earth and the other planets formed at essentially the same time from the same primordial material as the Sun.

This nebular hypothesis indicates that the solar system evolved from an enormous rotating cloud called a solar nebula that was composed mostly of hydrogen and helium. This nebula is believed to have begun contracting about 5 billion years ago, assuming a flat, disk shape with a proto-sun (pre-Sun) at the center.

From this point, the planets began to form from metallic and rocky clumps of substances, leading to a layered structure.

Origin of the Earth

Formation of Earth’s Layered Structure

As the Earth formed, the decay of radioactive elements and heat from high-velocity impacts caused the temperature to increase throughout the “planet”

Iron and nickel began to melt and sink toward the center

Lighter rocky components floated outward, toward the surface

Layers were formed according to density

The Earth’s CrustThe crust is the outermost, and best-known, layer of the

Earth.

Characteristics: Coolest layer of Earth Approximately 30 miles thick Thin, rigid layer floating on the mantle Composed of three major rocks groups Composition includes primary elements of Si, O, Fe, Al, Ca,

and Na, with most prevalent being the rock forming group Silicates (Si, O)

Two types of crust:1. Continental (Primarily Granite)2. Oceanic (Primarily Basalt)

Mohorovicic Discontinuity (Moho)

Between the between the crust and mantle there is an actual boundary, called the Mohorovicic (MOE-hoe-roe-VIT-jich) Discontinuity. (Moho Layer)

The depth varies: About 3 miles (5 kilometers) beneath the

ocean floor About 25 miles (40 kilometers) beneath the

continents

Lithosphere

The rigid layer of the Earth’s surface - composed of the crust and upper most part of the mantle.

Characteristics: Broken into a number of plates Floats on a denser, more plastic like layer of

upper mantle Distinguished from asthenosphere based on

how easily it flows

Mantle

The mantle is the thick layer of hot, solid rock located between the Earth’s crust and the molten iron core.

The mantle makes up the bulk of the Earth, accounting for 2/3 of the planet's mass, starting about 30km down and is about 2,900km thick.

The Earth’s mantle can be divided into two parts:1. Asthenosphere (upper mantle)2. Mesosphere (lower mantle)

Asthenosphere

The denser, more plastic layer of the upper mantle.

Characteristics: Partially molten Deformable region Temperature and pressure lead to partial

melting of rock and loss of strength of layer Low seismic activity within this region Behaves like hot asphalt

Mesosphere

Beneath the lithosphere and asthenosphere, classified as the lower mantle.

Characteristics: Increase in pressure (due to increasing

depth) Material is all solid but will convect slowly

due to temperature gradients and density differences

CoreThe core is the deepest and hottest layer of the Earth,

made almost entirely of metals. Like the mantle, the core is also divided into two parts:

1. Outer Core Approximately 1,430 miles thick Hot Liquid (estimated between 7,000-9,000 degrees Fahrenheit) Composed primarily of iron and Nickel

2. Inner Core Approximately 750 miles thick Despite the intensive heat (9,000-13,000 degrees Fahrenheit) it

is solid due to the intense pressure from the rest of the planet Composed primarily of Iron

“A Slice of Earth” Diagram Activity

Structure of the Earth

Within the Earth, scientists have developed four main systems. (Some argue 5)

Each system is unique, but interacts with the others.

None of the systems are independent of the others, nor of the global system of the Earth itself.

The Earth’s Systems

Click icon to add picture

The Geosphere

The Geosphere is based on the composition (chemistry) differences of:

• Crust

• Mantle

• Core

Divisions of the outer portion are based on how the materials behave.

The Crust: 1. Continental – made primarily of

granite 2. Oceanic – made primarily of basalt

The Mantle: Composed primarily of peridotite Parts of the mantle are solid, but some

act more as a liquid

The Core: Composed primarily of iron and nickel Outer Core is liquid Inner Core is solid

The Hydrosphere

The hydrosphere covers approximately 71% of the Earth’s surface, with the most prominent feature being the ocean.

The hydrosphere, ultimately, is comprised of all of the water on Earth. Oceans and seas Lakes, rivers, and ponds Glaciers and ice caps Groundwater Water in the atmosphere

Hydrosphere composition: 97% salt water 3% fresh water

About ¾ of the freshwater is contained in glaciers and icebergs

The Cryosphere

Sometimes considered part of the Hydrosphere

Contains all of the water that is in the form of ice Ice caps Snowfields Glaciers Ice sheets Sea ice Frozen ground

(permafrost) 99% of Earth’s

freshwater is contained in the Greenland and Antarctic ice sheets

The Atmosphere

Blanket of gases that surrounds our planet

Necessary for respiration of most living things

Protects inhabitants from radiation of Sun

Maintains suitable temperature for life

Current Composition: 78% Nitrogen 21% Oxygen 1% Other gases(water vapor, argon, carbon dioxide, trace gases)

The Biosphere

Includes all organisms on Earth as well as the environments in which they live.

The majority of the Earth’s organisms live within a few meters of the Earth’s surface; however, some live deep beneath the ocean surface and some live high atop the Earth’s mountains.

The Earth’s biosphere is unique in that scientists have yet to confirm evidence of life on other planets or elsewhere in the galaxy.

Extreme influences on other three spheres

A Complete System

The Earth is a dynamic body with many separate but highly interacting parts, or spheres.

Earth system science is the study of the Earth as a system composed of numerous parts, or subsystems.

System - any size group of interacting parts that form a complex whole

Two Types: Closed systems – self-contained (e.g. an

automobile cooling system) Open systems – systems where both energy

and matter flow into and out of the system (e.g. a river system)

The Earth as a System

An endless array of subsystems: Hydrological Cycle Carbon Cycle Nitrogen Cycle

Sources of energy: The Sun

Drives external processes Weather and climate Ocean circulation Erosional processes

The Earth's interior Drives internal processes Volcanoes Earthquakes Mountains

All science is based on the assumption that the natural world behaves in a consistent and predictable manner.

News/media and many people in "authority" misunderstand the nature of scientific inquiry. For instance, they often indicate through news media that "It's only a theory . . . ", insinuating that there is no proof, experiments, or observations behind the concept.

The Nature of Scientific Inquiry

Hypotheses and Theories

A tentative (untested) explanation of a natural phenomena

A hypothesis must be testable

A hypothesis may change or be modified with the discovery of new data

A basic principle describing the behavior of a natural phenomena

Well tested

Can be thought of as a “rule,” although the cause may be unknown.

Events are observed to be the same every time

Hypothesis THEORIES

Scientific Law

Describes the behavior of natural phenomena (rule of nature such as the Law of Gravity.)

An explanation based on many observations during repeated experiments.

Valid only if it is consistent with every other experiment that is done on it.

May change or be modified with the discovery of new data.

LAWS

Methods of Scientists

Scientific Method

Determine the problem

Make a Hypothesis

Experiment

Independent Variable

Dependent Variable

Constant

Control

Collect Data

Analyze the Results

Draw Conclusions

Repeat

What is the Scientific Method?

A procedure used to scientists to test hypothesis by making predictions about the outcome of the experiment BEFORE it is performed is referred to as the scientific method.

Experiment Factors: Independent Variable: factor manipulated BY the experimenter Dependent Variable: Changes due to the individual

experiment Constant: Variables do not change Control: “Base Group” for the experiment

Data: Quantitative: can be ordered (weight, temperature) Qualitative: different in types – NOT ordered (gender, species)

Science and Technology

The application of scientific knowledge and discoveries.

Transferrable – can be applied to new situations.

Can be good OR bad… Good – computers, health

care Bad – air pollution,

deforestation, eliminates jobs

Technology

Safety in the Science Lab

1. Understand all safety symbols before beginning 2. Wear safety goggles when using chemicals 3. Tie back long hair / loose clothing 4. Always slant tubes AWAY from yourself and others 5. Never Eat / Drink in the lab. Use only laboratory

glassware for experiments. 6. Never inhale chemicals or taste substances 7. Know what to do in case of a fire! 8. Report any spills, accidents or injuries to your teacher

immediately 9. Clean up your space! (Dispose properly of chemicals as

directed by your teacher.) 10. Always wash your hands, thoroughly, with soap and

water after working in the lab

Measurement

Using measurements is common when conducting science experiments.

A measurement includes using both a number that identifies how many units there are and a unit of measure.

Most scientific studies and experiments use a standard system of units called Le Systeme International d’Unites (SI). SI is the modern version of the metric system Based on a decimal system that uses the

number 10 as the base unit

Measurement Conversions

Prefix Symbol Meaning kilo k one thousand

hecto h one hundred

deka da ten

-- (B)… m, L, g BASE UNIT

deci d one tenth

centi c one hundredth

milli m one thousandth

Length

The standard SI Unit to measure length is the meter (m) A meter is divided into

100 equal parts, called a centimeter (cm)

A centimeter is divided into 1000 equal parts, called a millimeter (mm)

What does this all mean?

1m = 100cm = 1000 mm

Weight and Mass

The measure of the gravitational force on an object.

Varies with location, based on gravitational force (ie… a person on the moon)

Measured with some type of scale

The amount of matter in an object, dependent upon the number of atoms that make up the object.

Mass does not change with an object’s position.

Measured with triple beam balance

WEIGHT MASS

Area and Volume

Area is the amount of surface included within a set of boundaries. Area is expressed in

square units of length, such as m2 or cm2

Area is determined by multiplying length x width (l x w)

Volume is the amount of space occupied by an object.

m3 for a solid object mL or L for fluid

objects 1mL = 1 cc = 1cm3

AREA VOLUME

Density

Density is the measure of the amount of matter that occupies a given space. Density is expressed in grams per cubic

centimeter (g/cm3), grams per milliliter (g/mL) or kilograms per cubic meter (kg/m3

Calculate density by dividing the mass of the matter by its volume (m/v)

Time & Temperature

The interval between two events is time Time is typically

measured with a watch or clock

Most precise measure of time comes from an atomic clock

The SI unit for time is the second (s)

The measure of the average vibrations of the particles that make up a material is temperature Particles that vibrate more

quickly have a higher temperature

Particles that vibrate more slowly have a lower temperature

Measured in degrees, with a thermometer, and on a Celsius scale in Science

TIME TEMPERATURE

FORMULAS

MEMORY

RECALL

Time = Mass (in kg) x 9.8m/s2

Area = length x width

Density = mass/volume

Volume = length x width x height

C to K = C + 273.16

K to C = K – 273.16

Scientific Notation

Expresses number as a multiple of tenExample: 1250000000000 = 1.25 x 1012

It is expressed as a number between 1 and 10, multiplied by a power of 10

The power is the number of places the decimal moves

A positive (+) moves the decimal to the left A negative (-) moves the decimal to the right

Examples:12500 = 1.25 x 104

.000125 = 1.25 x 10-4

Section 1.3 Communicating in Science

In Science, it is imperative to make all results available to others.

Why? So results can be verified So information can be

used by others to conduct new experiments

How? Lab Reports Graphs Models Theories / Laws

Lab Reports

A lab report is when you record and analyze information you collected during your experiment.

Lab Reports are used to draw conclusions based on your data.

Models

A scientific model is an idea, a system, or a mathematical expression similar to the idea being explained.

Fairly accurate representation of your experiment.

Can change as data is collected.

Graphs

Used to show comparisons between data within your experiment.

Each graph must have: 1. Title 2. Labeled Axis 3. Legend / Key 4. Must be completed

in pencil

Steps to Making a Graph

1. Determine the variables and label each axis Dependent variable goes on the y-axis (vertical) Independent variable goes on the x-axis (horizontal)

2. Determine the scale of the graph Determine the number value for each square on the graph Spread the graph out to take up the most equal amount of

space

3. Plot the data points Mark each data value with a dot

4. Draw the graph Draw a line that best fits the data points If there is more than one line on the graph, you must

include a key identifying each line

5. Give the graph a descriptive title