Introduction to Earth Science

Scientific Method & the Metric System

Introduction to Earth ScienceIntroduction to Earth Science

Scientific Method and theMetric System

The Nature of Science

• The goal of science is to understand the world around us

• Special methods help to determine truths about nature

Branches of Earth Science

The three main branches of science are:

•Life Science

•Earth Science

•Physical Science

Earth Science

•Earth science deals with the study of the Earth, its history, changes, and its place in the Universe

•There are four branches of earth science

Branches of Earth Science

• Geology- Earth’s origin, history, and structure

• Meteorology- Earth’s atmosphere & weather

• Oceanography- Earth’s oceans, including their physical features, life forms, and natural resources

• Astronomy- Planets, stars, and other objects in space

The Scientific Method

• An orderly, systematic approach to problem solving

• The way scientists, and non-scientists, look for answers• There are seven basic steps to the scientific method

Step 1: Stating the problem

–Decide what you

want to know

–State the problem

in the form of a

question

Step 2: Gathering information on the problem

–Research what’s

already known

–Collect

information

and facts

Step 3: Forming a hypothesis

- A hypothesis is a

proposed solution

to a scientific problem

– There are two main parts to a

hypothesis

1. An explanation- why it will happen

2. A prediction- what will happen

Step 4: Experimenting

– Perform one or more

experiments to test the

hypothesis

– When performing experiments:

1. Divide subjects into test groups

2. In each experiment you should have a control group, that doesn’t get any of the variable, and several test groups

3. Keep everything, except the amount of the variable, the same between groups

Step 5: Recording and analyzing data

–Observe and write

down important

information (data)

–Organize data using graphs, tables, and charts

–Look for patterns or trends

Step 6: Stating the conclusion

–Look at data and

form conclusions

–Did the conclusions

support your hypothesis?

(why or why not?)

–Re-evaluate the hypothesis and formulate new questions

Step 7: Repeating the work

– In order for a hypothesis to be

excepted it has to be able to

withstand repeated testing

– After many experiments, where a hypothesis has continually been proven to be correct, it may be accepted by the scientific community and then considered to be a theory

– A theory is the most logical explanation for events that occur in nature

The Metric System

• A universal measurement system (also called the International System)

• Being based on multiples of ten makes it easy to use

• Uses prefixes to identify larger or smaller units of measure

Prefix Symbol Multiple

kilo K 1000

centi c .01

milli m .001

Metric Conversions - Length

Km m dm cmmm

x 1000 x 10 x 10 x 10

÷ 1000 ÷ 10 ÷ 10 ÷10

Metric Conversions - Volume

Kl l dl clml

x 1000 x 10 x 10 x 10

÷ 1000 ÷ 10 ÷ 10 ÷10

Metric Conversions - Mass

Kg g dg cgmg

x 1000 x 10 x 10 x 10

÷ 1000 ÷ 10 ÷ 10 ÷10

Length

• A measure of linear distance• Basic unit of length is the meter (m)• Use a meter stick or metric ruler to make

measurements

•The entire meter stick represents one meter

•Each number represents a centimeter (there are 100 centimeters in a meter)

•Each little line is a millimeter (there are 1000 millimeters in a meter)

Area

• The amount of surface included within a set of boundaries

• Determined by measuring the length and width of an object, then multiplying

Length = 14 cm

Width = 7 cm

Area = 14 cm x 7 cm = 98 cm2

(Area is always expressed in square units)

Volume

• Volume is the space that an object occupies

• Represents the length, width, and height of an object

• For solids, measurements are based on units of length (ex. cm3) and can be calculated using specific formulas

Calculating the volume of a rectangle

Volume of a rectangle = length x width x height (l x w x h)

Length = 10 cmWidth = 3 cmHeight = 4 cm

Volume = l x w x h = 10 cm x 3 cm x 4 cm = 120 cm3

10 cm

4 cm3 cm

Calculating the volumeof a cylinder

Volume of a cylinder = x radius 2 x height ( x r2 x h)

= 3.14

Radius = ½ diameter = ½ 10 cm = 5 cm

Height = 20 cm

Volume = x r2 x h = 3.14 x (5 cm)2 x 20 cm = 3.14 x 25 cm2 x 20 cm

= 1570 cm3

Diameter = 10 cm

20 cm

Volume of a liquid

•A graduated cylinder is used to accurately measure the volume of liquids in milliliters

•Determine the volume in a graduated cylinder by reading the bottom of the meniscus at eye level

•Once the volume of a liquid is known, it can be converted to a “solid volume” by using the formula 1 ml = 1 cm3

Mass

•Mass is a measure of the amount of matter

•Mass is measured in grams using a balance

•The mass of an object remains the same, no matter where in the universe it is measured

WeightWeight is a measure of the gravitational force exerted on an object by a massive body

•Weight is measured in Newtons (N) using a spring scale

•Weight varies from place to place depending on the strength of the gravitational force

Gravity

Gravity is the force of attraction between objects

The strength of the gravitational force between objects depends on:

- the distance between the objects ( the gravitational force between objects decreases with distance) -Mass ( the greater the mass of an object, the greater it’s

gravitational force)

Density•Density is the mass of a specific volume of an object

•Density is calculated by dividing the mass of an object by its volume

•Units for density are usually expressed in grams per cubic centimeter (g/cm3 )

•Since the density of water is 1 g/cm3 anything with a density less than 1 g/cm3 will float in water and anything greater will sink