WHAT IS SCIENCE?
How we know what we know
The Nature of Science
1. Science is a path to gaining knowledge about
the natural world
2. Science does not rely on faith or opinions
3. Science is in the realm of facts and
observations
4. Science does not make moral judgments
5. Scientific ideas can change if we gather more
data or learn more
Scientific Method
1. A series of steps that help
investigate a question
2. All things can be explained through
natural processes
3. Based on data and observations
4. Free from religious/cultural
interference
Question
Conclusion
Research
Data
Hypothesis
Experiment
Question
1. Begin with a testable question then try to
answer the question with evidence and logic
a) Example:
i.
Why are there more earthquakes in California than
in North Carolina?
ii. Why is the sky blue?
2. Some questions are impossible to test
a) Example:
i. Is there life after death?
ii. Do ghosts exist?
Research
1. Someone has probably asked this question
before.
2. Scientists keep good records, read a lot, work
together, and share information.
a) Books, magazines, Internet, experts
3. Determine what is already known.
Hypothesis
1. Testable prediction based on
research
2. Must be something you can
measure and document
a) Not supernatural things
3. You are usually proving only a
tiny part of the problem
Experiment
1.Design a way to test your
hypothesis
2.Have as few variables as
possible
a)Independent Variables
b)Dependent Variables
c) All else should be constant
Variables
1. Independent Variable: The factor that the
experimenter will change or manipulate
a) Under the direct control of the experimenter
b) “manipulated variable”
2. Dependent Variable: The factor that changes based
on the independent variable
a) May or may not be different among the trials
b) NOT under the control of the experimenter
c) “measured variable”
Variables
1. The effects of independent variable on
dependent variable
2. Does the amount of sleep a student
gets affect his/her grades?
3. The effects of sleep on grades.
Constant
1. Constant: Anything that is not a
variable
a) Why is it important to keep everything
else constant?
Control
1. The standard for comparison that
will show the independent variable
was the cause of the results
2. Control group vs. Experimental
Group
a) Example: Drug trials  placebos
Data
1. Data: the information gathered during the
experiment
a) Displayed in the form of graphs, charts, or tables
b) May be quantitative or qualitative
c) There must be enough data points to prove your
claims
d) Everything must be measured properly
e) Notes and observations may also be important
Conclusion
1. Was your hypothesis supported?
2. What experiments need to be done in the
future?
3. Share data – Publish your results
4. Different people may have different conclusions
from the same data
Scientific Community
1. Scientific discovery works best with
collaboration
2. A hypothesis needs to be confirmed by
many different scientists before it can
become a theory
3. Scientists may publish their findings after
several scientists review the paper – this
is called “peer review”
Theory
1. If a hypothesis explains all the data and none
of the data contradicts the hypothesis, the
hypothesis becomes a theory
2. A theory is the simplest explanation that
explains observable facts
a) Examples: Germ theory of Disease, Theory of
Gravitation, Theory of Evolution, Atomic theory of
matter, Quantum Theory
3. Theories can be constantly tested and revised
Scientific Models
1. Scientists often cannot directly touch or
see what they are studying
2. Models are simpler representations of
complex real world phenomena
3. Models are useful for testing hypotheses
and making predictions about real world
events
3 Types of Models
1. Physical Model: physical representation of subject being
studied
a) Example: Globe or Map
2. Conceptual Model: ties together lots of ideas to create
an explanation
a) Example: Giant Impact Hypothesis
3. Mathematical Model: complex equations that take many
variables into account
a) Example: predicting the path of a hurricane
Earth Science
1. Main divisions of the earth
2. Geosphere: solid earth  Geology
Oceanography
1. Hydrosphere: water on earth  Oceanography
Meteorology
1. Atmosphere: gases around earth 
Meteorology
Biology
1. Biosphere: living things on earth  Biology
Environmental Science
1. Environmental Science: studies the effects
people have on their environment and living
things
Astronomy
1. Astronomy: study of outer space
Matter
1. Matter is anything that has mass and volume
a) Volume: the amount of space an object takes up
Atoms
1. The smallest unit of matter is the atom
Molecules
1. Atoms can be bonded together to form molecules
The delicate inner structure of a pentacene molecule
has been imaged with an atomic force microscope
Element
1. There are over 100 different kinds of atoms
a) Each type of atom has a different structure of
protons, neutrons, and electrons
2. An element is a substance in which all the atoms
have the same structure
States of Matter
1. Matter on Earth exists in one of three states:
a) Solid: atoms are moving very slowly (less energy)
Solid
(Definite Shape;
Definite Volume)
Liquid
a) Liquid: atoms are moving at intermediate speed
(intermediate energy)
Liquid
(Indefinite Shape;
Definite Volume)
Gas

Gas: atoms are moving very rapidly (more energy)
Gas
(Indefinite Shape;
Indefinite Volume)
Energy
1. All matter has energy
a) E=MC2
Add Energy
Solid
Add Energy
Liquid
Gas
Continents
1. Mostly granite
a) Less dense than ocean basins
2. Edges are often under water
3. Very old
a) Billions of years old
4. Subject to erosion and mountain
building
Ocean Basins
1. Mostly basaltic rock
a) Denser than granite
2. Covered with water
3. Young
a) Millions of years old
4. Constantly expanding and changing
Changing Earth
1. Earth’s surface is constantly changing
over short and long periods of time
2. Constructive forces – formation of new
landforms and seafloor
a) Volcanic activity or uplift of the crust
3. Destructive forces – modification of
existing landforms
a) Erosion and weathering
Constructive Forces
Destructive Forces
Direction
1. North and South Poles: where the
axis of rotation intersects with the
planet
2. In space there is no up or down, so
this system only works on Earth
3. Magnetic and Geographic Poles
are different
North on the Earth
Latitude and Longitude
1. Latitude
a) Equator: halfway between the poles0˚
b) North Pole: 90˚N; South Pole: 90˚ S
2. Longitude
a) Prime Meridian: not natural  0˚
b) International Date Line: 180˚
c) Everything else is given as number of
degrees East or West  79˚ W
Latitude and Longitude
1.Parallels = Latitude
a)All lines are parallel
2.Meridians = Longitude
a)All lines intersect at the Poles
Latitude and Longitude
1. LatitudeLadder
a) Evenly spaced steps
b) Each step takes you higher or lower
2. LongitudeLong
a) Longitude lines are longer than most
latitude lines
b) Every longitude line is equally long
Latitude and Longitude