Chapter 2Science, Systems, Matter and

Energy!

Section 1The nature of Science

Easter Island• Easter Island (Rapa Nui)

colonized by Polynesians 2,500 years ago.

• Originally it had lush forests buy the Polynesians harvested all the trees.

• The population flourished and soon the island was inhabited by up to 20,000 people.

• When the resources completely disappeared, the residents of Easter Island hunted and ate each other.

• Over the course of a couple hundred years, the population decreased to 2,000 people.

What is science and what do scientists do?

• What is science and what do scientists do?• Science- an attempt to discover order in the natural world

and use that knowledge to describe what is likely to happen in nature.

• Things scientists do:Collect scientific data

Scientists collect facts by making observations and taking measurements

Conduct ExperimentsScientists conduct many tests in which they repeatedly collect scientific data

Formulate HypothesesMany scientists come of with ideas that explain their observations

Develop ModelsA method that scientists use to test their hypotheses is to make a model or a simulation of what is being studied

Results of Science• Peer Review• Peer Review is when fellow scientists

(peers) read published experiments and can examine and criticize each others work

• Theories• Scientific theories are not guesses or

speculations• A scientific theory is a useful

explanation of a process of phenomena

• New evidence can modify, backup or even overturn theories

• Scientific Laws• A scientific or natural law is something

in nature that repeats itself thousands of times so that scientists can form concrete conclusions

• An example of this would be the Second Law of Thermodynamics

How do scientists learn about nature?

The scientific Process:• Observation: Nothing happens

when you turn on your flashlight• Question: Why didn’t the light turn

on?• Hypothesis: Perhaps the batteries

are dead.• Test the Hypothesis: Replace the

batteries.• Result: The flashlight still does not

work• New Hypothesis: Perhaps the bulb

is broken.• Experiment: Replace the bulb.• Result: The flashlight works.• Conclusion: The second

hypothesis was correct.

Aspects of an experiment

• Experiments have variables or factors that can influence every little part of them.

• Scientists prefer controlled experiments where there is little interference

What type of reasoning do scientists use?

• Inductive ReasoningInductive reasoning is when

a scientist uses observations and measurements to arrive at a conclusion or hypothesis

• Deductive reasoningDeductive reasoning is

when a scientist uses logic to arrive at a specific conclusion based on a generalization or premise

How valid are the results of science?

• Scientists can prove and disprove things

• Most things in science are not absolutely true

• The words projection, scenarios and likely are preferred instead of words like prediction, forecast and will

What is the difference between frontier science and sound

science?• Frontier Science is

science that is based on preliminary results and often is controversial because it has not been widely tested

• Sound Science is science that consists of data theories and laws which are generally more accepted by scientists

What is junk science and how can we detect it?

• Junk science is scientific results that are presented as sound science but have not been tested enough to be valid at all

• Some scientists and politicians badmouth valid science that does not support their agenda by calling it junk science

Section 2

Models and Behavior of Systems

Why are models of complex systems useful?

• System- a set of components that function and interact in some regular and theoretical understandable manner

• Systems have inputs, flows and outputs

• Models are used to evaluate systems

How do feedback loops effect systems?

• A feedback loop is when the output of a system is fed back as input and leads to a change in the system

• A positive feedback loop is when a system changes further in the same direction

Ex. Depositing money in a bank and gaining interest. The interest increases the balance which in turn increases the interest.

• A negative or corrective feedback loop is when a system changes in the opposite direction

Ex. Recycling aluminum cans. Old aluminum cans are melted down and made into new aluminum cans with minimal waste.

How do time delays effect complex systems?

• Time delays occur often in complex systems.

Ex. A smoker who is exposed to the toxins in the cigarette may not develop lung cancer for many years.

• Time delays allow the problem or a factor in an experiment to build up until it reaches a threshold level which causes a fundamental shift in the experiment.

What is synergy and how does it affect complex systems

• A synergistic interaction is when two or more processes interact so that the combined affect is greater than the sum of their separate affects.

Ex. Two people can each lift 45 pounds. They work together and they can lift 100 pounds.

How can we anticipate environmental surprises?

• Many times there are environmental surprises or discontinuities

• When a threshold is crossed, surprises occur

• We can deal with this by never doing just one thing

Section 3

Matter

What types of matter do we find in nature?

• Matter- anything that has mass and takes up space

• Two chemical forms of matter:Elements- the distinctive building

blocks of matter that make up ever material substanceEx. N, H, P, Br

Compounds- two of more different elements that are held together in fixed proportions by attractive forces call chemical bondsEx. NaH2 Br4H2 HeF

What are nature’s building blocks?• Three things elements

are made of:Atoms- the smallest unit of

matter that exhibits the characteristics of an element

Molecules- combinations of two or more atoms of the same or different elements held together by chemical bonds

Ions- an electrically changed atom or combination of atoms

What are atoms made of?• Atoms are made up of different

subatomic particles each having a different change

• Parts of an atomProtons have a positive chargeElectrons have an electric chargeNeutrons have no charge• The atomic number of an element is

equal to the number of protons in the nucleus or center of an atom

• The mass number of an atom is the total number of neutrons and protons in the nucleus

• Some elements have different forms that have the same atomic number but a different mass number, these are called isotopes

Ex. Hydrogen-2

What are ions?• Ions are made when an element

loses or gains electrons• Unlike atoms, ions are not neutral

overall• Some atom tend to lose electrons

and form ions, like metals• They are known as electron givers• Nonmetals tend to receive

electrons and form ions• They are called electron receivers• The concentration of hydrogen

ions in an element is known as its pH level

• This determines whether it is an acid or a base

What holds the atoms and ions in a compound together?

• Chemical bonds hold different compounds

• Shorthand chemical formulas are used to show the number of atoms or ions of each type in a compound

• Compounds made up of oppositely charged ions are called ionic compounds

• Compounds made up of molecules of uncharged atoms are called covalent or molecular compounds

What are organic compounds?• Most of the chemicals in

the human body are organic compounds

• Organic compounds are organic because they have carbon in them

• There are natural organic compounds like proteins and fats

• There are also synthetic organic compounds like plastics and drugs

What are genes, chromosomes, and DNA molecules?

• DNA- Deoxy Nucleic Acid• RNA- Ribo Nucleic Acid• Genes- specific

sequences of nucleotides in a DNA molecule

• Chromosomes- combinations of genes that make up a single DNA molecule with proteins

What are inorganic compounds?

• Inorganic compounds are compounds that do not have carbon-carbon or carbon-hydrogen bonds

Ex. Salt, Water, Carbon Dioxide

What are four states of matter?• Three physical states of

matter:SolidLiquidGas• Plasma is the fourth state

of matter and is a high energy mixture of positively charged ions and negatively charged electrons

What is matter quality?• Matter quality- the measure of

how useful a form of matter is to us as a resource

• High quality matter is matter that is concentrated and is usually found near the surface of the earth

• Low quality matter is watered down and can be found deep underground

• The total amount of material needed to produce a certain amount of a product is called the material efficiency or resource productivity

Section 4

Energy

What is energy?• Energy- the capacity to

do work and transfer heat• Two types of energy:Kinetic energy is energy that

is possessed by matter because of its speed or velocity

Potential energy is energy that is stored and available for use

What is electromagnetic radiation?• Electromagnetic radiation is a

type of energy that is a wave• The distance between the

peaks of an electromagnetic wave is called its wavelength

• Radiation that has enough energy to change atoms into positively changed ions are called ionizing radiation

• Other forms of radiation are called nonionizing radiation

• Visible light is a form of nonionizing radiation

What is heat and how is it transferred?

• Heat- the total kinetic energy of al the moving atoms, ions, or molecules within a given substance excluding all overall motion of the whole object

• Temperature- the average speed of motion of the atoms, ions, or molecules in a sample of matter at a given moment

• Heat can be transferred from one place to another

What is energy quality?• Energy quality- a

measure of an energy sources ability to do useful work

• High quality energy is concentrated and can do useful work

• Low quality energy is dispersed and has little ability to d useful work

Section 5

The Law of Conservation of Matter

What is the difference between a physical and chemical change?

• When matter is shifted so that its chemical composition is not changed, it undergoes a physical change

• A chemical change, sometimes called a chemical reaction, occurs when the chemical composition of a compound changes

The law of conservation of matter: why there is no “away”

• THE LAW OF CONSERVATION OF MATTER:

MATTER CAN NEITHER BE CREATED OR DESTROYED

• Translation- Everything that we use, eat, or throw away is still here in one form or another

• There is no away, you cannot throw away matter forever because it changes

How do chemists keep track of atoms?

• When an element changes its chemical composition, it still has to have the same amount of atoms

• To measure this, scientists use a balanced chemical equation

Ex. C + O2 = CO2

How harmful are pollutants?• Three factors that determine the

severity of pollutants harmful effects:Concentration- this is the potency of a

chemical and is expressed in PPM or parts per million

Persistence- this is how long the chemical stays around in the air, water, and ground

Chemical nature- this is how bad the chemical is and what it does

• Three types of pollutants:Degradable- natural processes break

down the chemicals so that they are at acceptable levels

Slowly Degradable- these chemicals degrade but can take decades

Nondegradable- chemicals that natural processes cannot break down

Section 6

Nuclear Changes

What is natural radioactivity?• The third type of change that

matter can undergo is called a nuclear change

• When isotopes emit particle, it is called radioactive decay

• Unstable isotopes are called radioisotopes or radioactive isotopes

• Two most common particles:Alpha particles- fast moving

protonsBeta particles- fast moving

electrons

What is nuclear fission?• Nuclear fission- a change

in which nuclei of certain isotopes with large mass numbers are split into lighter nuclei when struck by neutrons

• One fission leads to another; this is called a chain reaction

• An example of this is the atomic bomb

What is nuclear fusion?• Nuclear fusion- a nuclear

change in which two isotopes of light elements such as hydrogen are forced together at extremely high temperatures until they fuse to become a heavier nucleus

• Nuclear fusion is more difficult to initiate but also produces more energy

• Fusion powers the stars

Section 7

Energy Laws: Two Rules We Cannot Break

What is the first law of thermodynamics?

• Energy can neither be created nor destroyed

• Is the same as the law of conservation of energy

• Energy input equals energy output

• Cannot get something for nothing

What is the second law of thermodynamics?

• When energy is changed from one form to another, some of the useful energy is always degraded to lower quality, more dispersed, less useful energy

• Translation- When energy is changed from one form to another, it changes to lower quality energy

• Energy efficiency or energy productivity is how much useful work can be accomplished by a particular input of energy

Section 8

Matter and Energy Laws and Environmental Problems

What is a high-throughput economy?

• A high throughput economy is a high waste economy

• Most today’s countries add a lot of waste and heat to the environment

• Eventually the amount of waste being produced will exceed the capacity of the environment and nature will no longer be able to dilute out pollutants

What is a matter-recycling-and-reuse economy?

• A matter-recycling-and-reuse economy is an economy that reuses waste instead of dumping it into our environment

• This gives us more times until the environment cannot handle our waste

What is a low-throughput economy?

• A low-throughput economy is a low waste economy

• It means people have to recycle, conserve energy and control population growth

• This helps us maintain an environmental equilibrium

Sources

• Living in the EnvironmentTyler Miller Jr.• www.wikipedia.org• www.webelements.com• www.antoine.frostburg.edu• http://webbook.nist.gov/chemistry/

MC TO THE G-RAW!!!