Science: Matter, Energy, and Life
Intuition leads to the flat Earth society and bloodletting; experiments lead men to the moon and microsurgery.
- Seth Mnookin
SCIENCE AS A WAY OF KNOWING
• Science assumes that the world is knowable.
• Science seeks to…
- Search for testable evidence.
- Form hypotheses and theories.
Hypothesis: Prediction based on prior
knowledge and observation.
Theory: Broad explanation based on
many experiments and high amounts
- Find additional evidence to strengthen or
disprove current theories. 2
SCIENCE AS A WAY OF KNOWING CONT’D
• Scientists never work alone; they always
collaborate as part of the process.
They check each other for errors.
Divide up a problem and work on it in
• Appears or claims to be science, but does
not follow scientific principles.
The Earth is Flat
Geocentric Solar System
• Many computers only used two digits to store the date, so
when the new year hit, they would revert to 1900 instead of
• Fears: Computers controlling power grids, nuclear reactors,
weapons, would fail.
Japan had a nuclear power plant false alarm go off.
Australia had two bus station ticket machines shut down.
150 slot machines in Delaware shut down.
The clock on the U.S. Navy’s website had the incorrect
• The Mayan Calendar ends on December 21,
• A huge sunspot or sunflare will cause a polar
reversal, causing the Earth to spin in the
Earthquakes, tidal waves, volcanic
eruptions will follow.
Experiments must be designed and
recorded such that they can be exactly
reproduced by other researchers.
• Controlled Studies
Comparisons are made between
experimental and control populations.
• There are many examples of published studies or report that
have been later found incorrect, misleading, or fraudulent.
• These are always detected, eventually due to the scientific
method and peer review.
The net effect is loss of time, resources, and public
• Significant recent examples:
MMR Vaccine / Autism study
Speed of Himalayan glacier melting
Human stem cell cloning study
Information gathered by sight, sound,
smell, or touch.
- Example: Mussels are disappearing from a
nearby river, which is being polluted.
A testable explanation for an observation.
- A hypothesis can be proven wrong, but
never proven true.
- Ex: Fertilizer from a nearby golf course is
washing into the river and killing the mussels.
What will happen if the hypothesis is correct?
- Ex: Mussels will die when exposed to the
Test hypothesis under controlled
Variable: Factor of interest that is
- Ex: Fertilizer pollution
Experimental Group: Receives the
- Ex: Exposed mussels
Control Group: Does not receive
- Ex: Mussels in clean water 19
• Data Analysis
Organize data from
experiment into graphs
Compare the results
with the hypothesis.
Results are published
and reviewed by others
to check for errors. 20
Modeling and Natural Experiments
• Modeling - Simulating the phenomenon
under study in a laboratory.
Pro: More control over experiment
Con: All variables must be understood.
• Natural – Conduct study in the field under
Pro: Provides a more accurate
Con: More difficult to study
Case Study: John Snow and Cholera
• London in 1854 was suffering
from a severe cholera
vomiting, paralysis, death.
• John Snow did interviews
and mapped the locations of
Cholera in London
Other Factors Affecting Experiments
An attempt to measure and predict the likelihood of an
- Flip a coin, probability of tails?
- Probability of tails twice in a row?
• Sample Size
The number of observations used in an experiment or
- Higher sample size = lower margin of error
Do the researchers have something to gain if the
experiment yields certain results?
Combating Bias: Scientific Design
• Blind Experiment
Conducted so the experimental subjects
do not know which is the control and which
is the experimental group.
- Eliminate the “placebo effect”
Neither the subject nor the investigators
know which participants are receiving an
Minimizes risk of bias.
PRINCIPLES OF MATTER AND ENERGY
• Matter - Has mass and takes up space.
• Law of Conservation of Matter
Under normal conditions, matter cannot be
created or destroyed.
- There is no away.
• Energy - The capacity to do work.
- Energy contained in moving objects.
- Stored, latent energy available for use.
• Heat - Energy that can be transferred
between objects of different temperature.
• First Law
Energy is neither created nor destroyed,
but can be transferred or transformed.
- All energy sources are finite.
• Second Law
With each energy transfer or
transformation, some energy is lost as
- No process is 100% efficient.
Second Law of Thermodynamics
Solar Chemical energy energy (moving,
Waste Waste Waste Waste
heat heat heat heat
Fig. 2-11, p. 32
BUILDING BLOCKS OF LIFE
• Atom - Smallest particle that exhibits the
characteristics of an element.
Protons - Positively charged.
Electrons - Negatively charged.
Neutrons - Neutral.
BUILDING BLOCKS OF LIFE CONT’D
Two or more atoms chemically bonded
- Can be an element (like O2)
- Can be a compound (like CO2)
A molecule that contains more than one
type of atom.
Acids and Bases
• Acids are compounds that release hydrogen
ions (H+) in water.
• Bases are substances that release hydroxide
ions (OH-) in solution.
• Strength of acids/bases is measured by
concentration of H+.