Chapter 2 – Science, Matter, Energy Chapter 2 – Science, Matter, Energy and Systemsand Systems

Endeavor to discover how nature works and to use that knowledge to make predictions about what is likely to happen in nature.

Science Science is a discipline that attempts to

describe the natural world in terms of order. Biology Chemistry Physics Earth Science

InferenceInference1. To conclude from evidence or premises

2. To reason from circumstance; surmise: We can infer that his motive in publishing the diary was less than honorable

3. To lead to as a consequence or conclusion: “Socrates argued that a statue inferred the existence of a sculptor”

Scientific methodScientific method HYPOTHESIS – proposed to

explain observed patterns Critical experiments Analysis and conclusions

Scientific MethodsScientific Methods What is the question to be answered? What relevant facts and data are known? What new data should be collected? After collection, can it be used to make a

law? What hypothesis can be invented to explain

this? How can it become a theory?

Theory and LawTheory and Law Scientific Theory

A hypothesis that has been supported by multiple scientists’ experiments in multiple locations

A Scientific Law a description of what we find happening in

nature over and over again in a certain way

Scientific LawsScientific Laws Law of Conservation of Matter

Matter can be changed from one form to another, but never created or destroyed.

Atomic Theory of Matter All matter is made of atoms which cannot be

destroyed, created, or subdivided.

ReasoningReasoning Inductive Reasoning

Uses observations and facts to arrive at hypotheses

All mammals breathe oxygen.

Deductive Reasoning Uses logic to arrive at a specific

conclusion based on a generalization All birds have feathers, Eagles are birds,

therefore All eagles have feathers.

Frontier and Consensus ScienceFrontier and Consensus Science Frontier Science

Scientific “breakthroughs” and controversial data that has not been widely tested or accepted

String Theory Consensus or Applied Science

Consists of data, theories, and laws that are widely accepted by scientists considered experts in the field involved

Human Genome Project

Models Scientists use models to imitate the system.

Mice are used to determine LD50

Chemists use structural models when investigating a chemical

Remember the plum pudding! Mathematical and computer models are able

to predict many outcomes

Models have Factors Factors represent the variables in a

scientific theory The factors that are involved in a theory

about why you are late to my class your walking speed interference by your peers the distance from point A to my room

A Good Scientist . . . Always makes observations. Always questions. Always using good scientific practices to

record and analyze data. Repeats trials Uses statistics to analyze data Uses safe and accepted practices Uses data to support hypotheses

ExperimentsExperiments Variables are what affect processes in the

experiment. Controlled experiments have only one variable Experimental group gets the variable Control group does not have the variable

Placebo is a harmless pill that resembles the pill being tested.

In double blind experiments, neither the patient nor the doctors know who is the control or experiment group.

Let’s Enter the New Age of Science Six Sigma (6δ) is an industry wide method

of materials and production management Six sigma utilizes International Standards

Organization (ISO) guidelines to effectively manage industrial processes.

The goal of 6δ is total customer satisfaction through lowering cost, faster and more efficient production, and zero-defect products.

6δ Problem Solving Strategies We are going to apply these principles to

the scientific process Knowledge Based Management: taking

the questions to ask, the questions to answer and the tools and techniques to answer them.

Process Flow DiagramInput

Decision

Yes

Process

Output

No

Observation

Hypothesis

Experiment

Data

Conclusion

Variables A variable is a source or variance in an

experiment and include independent and dependent variables. Independent variable (x-axis): the variable

which is changed in an experiment.

Dependent variable (y-axis): the variable which is measured in an experiment.

Identifying Variables The 6 method of problem solving uses a

“fishbone” diagram or a cause-and-effect diagram.

The variables are: Man -

Environment Machine - Method Measurement - Materials

Cause and Effect Diagram

Man Machine Measurement

Effect

Method Materials Environment

Measurements In science, data is collected through

observations and measurement.

A measurement has magnitude, units,and some degree of uncertainty.

Units A number by itself means nothing! (unless it

is meant to stand along like specific gravity) Scientists use ppm (part per million) to

measure pollutant concentration concentration = mass solute per volume of

solution!!! ppm means 1 mg per 1000mL (1 mg/L) ppb means 1 ug/L

AccuracyAccuracy Vs Precision Vs PrecisionAccuracy – measurement agrees with the

accepted correct value

Precision – measure of reproducibility

Adjustments If your data is precise, but not accurate,

simply adjust your measurement techniques.

If your data is neither precise nor accurate, you will need to adjust the equipment and the procedure.

Time Delay Science does not always occur

instantaneously. There is often a time delay from the introduction of a variable until observable effects. Short time delay: ice on a stove = melts quickly Long time delay: ice in a refrigerator = melts

slowly Name some in the environment!

Significance of Numbers Each number of a measurement is

significant (has meaning), including the last digit. The last digit is estimated.

Significant Figure Rules All non-zero numbers (1-9) are significant. Zeros are significant if they come between

two significant figures. Zeros are significant to the right of the

decimal IF they follow a significant figure. (0.0000100000)

Trailing zeros to the left of the decimal are only significant if there is a decimal.

Calculating With Sig Figs When there are multiple functions, complete

all functions and determine significant figures at the end.

The least number of decimal places or significant figures determines the number in the final answer. Adding/Subtracting: only count decimal places. Multiplication/Division: count significant

figures.

Example50.222 + 34.22 x 10.00000 =

3 decimal places + (4 sig figs x 7 sig figs)

50.222 + 342.00000=

392.422answer should have 4 sig figs with no more than 2 decimal places

392.4That’s your final answer

Long Division and Multiplication Practice dividing and multiplying the

following by hand 1520 ÷ 23 70 ÷ 1.35 1.2 x 1023 ÷ 2.4 x 10-3

50222 x 233 100000000 x 340000 75002 x 0.00123

Scientific Notation Used to express very large or very small

numbers Multiplying and dividing factors

multiply, add exponents divide subtract exponents

Percentages A percentage is a ratio of 100 5% is 0.05 x 100 What is 3.5% of 1,999,220? What percentage of animals is 255 out of

3420?

Dimensional Analysis You MUST solve all problems using this

format known x conversion factor = answer

If you have 2.35 kg of a sample whose density is 1.25 g/mL, how many Liters of sample do you have?

Chemistry Review

Compound (molecule)

What does it matter?Matter

Pure Substances Mixtures

Element (atom)

Homo-geneous

Hetero-geneous

Laws of Matter Law of Conservation of Matter: matter is

neither created nor destroyed, it simply changes form.

Law of Definite Proportions: atoms come together in small whole number ratios to form unique chemical compounds.

States of Matter Solid: atoms do not move and are close

together in a fixed volume and shape. Liquid: atoms move freely within the

shape of the container with a fixed volume. Gas: atoms move freely far apart from

each other; no fixed volume or shape.

Atoms Nucleus made up of Protons (+) and

Neutrons (neutral) Atomic Mass Number

Electrons (-) arranged in orbitals around the nucleus

Atomic Number: number of protons Isotope: same number of protons, different

number of neutrons

Ions Ion: an atom with a charge

Cation: positive ion Anion: negative ion

pH: measure of -log10[H3O+] measure how acidic or basic (0-14 S.U.)

Physical and Chemical A physical property describes a chemical

using the five senses. Physical change involves the change in a

physical property. A chemical property describes the relative

ability of a chemical to react. Chemical change results in a new compound.

Matter qualityMatter quality Measure of how useful a matter is

for humans based on availability and concentration

Some Important elements- composition by Some Important elements- composition by weight – only 8 elements make up 98.5% of weight – only 8 elements make up 98.5% of the Earth’s crustthe Earth’s crust

Organic Organic compounds are Carbon based.

The backbone of the compound is Carbon with Oxygen, Hydrogen, Nitrogen, etc. at specific locations

Organic CompoundsOrganic Compounds with carbon sugar, vitamins, plastics, aspirin

Inorganic compoundsInorganic compounds no carbon,not originating from a living

source Earth’s crust – minerals,water water, nitrous oxide, nitric oxide,

carbon monoxide, carbon dioxide, sodium chloride, ammonia

Biological Matter Prokaryotes: unicellular, without nuclear

membrane Bacteria

Eukaryotes: multicelluar organisms with cellular and nuclear membranes algae, fungi, animals, etc.

Macromolecules Macromolecules are very large molecules

proteins amino acids DNA

Genes are collections of nucleotides in a strand of DNA which express physical characteristics; all genes together form a Chromosome

EnergyEnergy capacity to do work and transfer heat Kinetic Energy -energy in action electromagnetic radiation, heat,

temperature Potential energy - stored energy that is

potentially available

Energy sourcesEnergy sources 97% solar without it earth’s temperature -

240 C 1% - non commercial(wood, dung,

crops) + commercial ( burning mineral resources)

Energy qualityEnergy quality

Measure of how useful an energy source is in terms of concentration and ability to perform useful work

Electromagnetic Radiation Electromagnetic Radiation is a self-

propagating wave that moves through space or matter. Electric and Magnetic components It has properties of waves.

Electromagnetic radiationElectromagnetic radiation

different wave lengths shorter – high energy, disrupts cells with long term exposure

Use….radioisotopesUse….radioisotopes Estimate age of rocks and fossils Tracers in pollution detection and

medicine Genetic control of insects

1st Law of Energy or 1st Law of 1st Law of Energy or 1st Law of ThermodynamicsThermodynamics

in all physical and chemical changes energy is neither created or destroyed

energy input always equal to energy output

2nd Law of Energy or 2nd Law of 2nd Law of Energy or 2nd Law of ThermodynamicsThermodynamics

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(heat)

Nuclear Material An atom will release energy as

electromagnetic radiation in order to become stable.

A stable nucleus has at least as many or more neutrons as protons.

Atoms with a mass #209 or greater are never stable.

Nuclear ChangesNuclear Changes nuclei of certain isotopes spontaneously change

(radioisotopes) or made to change into one or more different isotopes

Alpha particles – fast moving (2 protons+2neutrons); Beta particles – high speed electrons ; Gamma particles - high energy electromagnetic radiation

radioactive decay, nuclear fission, nuclear fusion

Nuclear Fission Nuclear fission is the process of splitting

atoms. Fissile isotopes are isotopes of an element

that can be split through fission. Only certain isotopes of certain elements are

fissile. For example, one isotope of uranium, 235U, is fissile, while another isotope, 238U, is not.

Nuclear FissionNuclear Fission certain isotopes (uranium 235) split apart into lighter nuclei when struck by neutrons

chain reaction releases energy

needs critical mass of fissionable nuclei

Nuclear fusionNuclear fusion two isotopes (hydrogen) forced together at

extremely high temperatures (100 million C)

uncontrolled nuclear fusion thermonuclear weapons

Nuclear Fusion Nuclear fusion is the joining of two atomic

nuclei. It occurs in stars all over the universe, including our Sun, and is what provides the warmth and light we receive.

1H + 1H 2H + positron (ß+) + neutrino (v)2H + 1H 3He + gamma ray (y)

3He + 3He 4He + 1H + 1H

Decay Radioactive decay is when unstable

isotopes emit particles. There are three main types of radiation:

* Alpha radiation

* Beta radiation

* Gamma radiation

Half Life The rate of radioactive decay is related to the

energy change that accompanies the transformation, but it is not a direct relationship.

The rate of radioactive emissions of a radioactive nuclide is directly proportional to the amount of radioactive material present.

The rate of decay of a radioactive nuclide is measured by its half-life.

The half-life of a radioactive substance is the time it takes for half of an initial amount of the substance to decay.

The half-live is independent of chemical activity, external pressure, and temperature.

Half-Life Formula T = half life t = total time elapsed Fraction remaining = 1/2 (t/T)

Number of half-life periods = t / T

Uranium Uranium is the principle element used in nuclear

reactors and in certain types of atomic bombs. The specific isotope used is 235U.

235U + 1 neutron 2 neutrons + 92Kr + 142Ba + ENERGY

235U + 1 neutron 2 neutrons + 92Sr + 140Xe + ENERGY

Chain Reaction When the atom is split, 1 additional neutron is

released. If more 235U is present, those 2 neutrons can cause 2 more atoms to split. Each of those atoms releases 1 more neutron bringing the total neutrons to 4.

The chain reaction will continue until all the 235U fuel is spent. This is roughly what happens in an atomic bomb. It is called a runaway nuclear reaction.

Positron is a positive electron e+

Gamma rays are electromagnetic radiation with a lot of power

Feedback LoopsFeedback LoopsA feedback loop

occurs when an output of a system is fed back as an input

Two kinds of feedback loops Positive Negative

Positive Feedback A feedback loop in which output of one

type acts as input that moves the system in the same direction. The input and output drive the system further toward one extreme or another. Positive feedback will result in exponential

(unlimited) growth. Positive feedback is BAD

Positive feedback loopPositive feedback loop

Exponential growth of population – more individuals lead to increased number of births

Negative Feedback A feedback loop in which the output of one

type acts as input that moves the system in the opposite direction. The input and output essentially neutralize each other’s effects and stabilizes the system. A thermostat in a room controls and

maintains the temperature. Negative feedback is GOOD

Negative feedback loopNegative feedback loop

Temperature regulation in humans – increased temperature leads to decrease in temperature by sweating

High Throughput A high throughput economy is one that has

a high output. The economy is boosted by a one-way flow

of matter/energy Generates a large amount of waste and

pollution Energy output is low quality

Low Throughput A Low Throughput economy is one that

has a balance of input and output. Generates little waste Maximizes energy efficiency Not an economic leader but a environmental

leader

Recycling and Reuse A Recycling and Reuse economy mimics

nature by recycling and re-using matter and energy. an environmentally sustainable economy

Pollutants

•Tying the themes together.

Pollutants Remember the definition of pollution?

The presence of chemicals at high enough levels to threaten the health of humans and other organisms.

The EPA uses a vague definition of pollutant to define environmental “hazard”

There are 5 types of pollution that we will focus on.

Persistent Persistent pollutants are those that can be

detected in the environment for a very long time. Bioaccumulative chemicals that cannot be

removed from the body of fish or other animals are stored in fatty tissue; other organisms store the chemicals in their cell wall or other cellular structures.

Rachel Carson highlighted DDT.

Degradable A degradable pollutant is one that is broken

down completely in the environment or reduced to an acceptable level. Just because a pollutant breaks down, the

products may be just as harmful!!! DDT degrades into DDE and DDD

Dicholorodiphenyltrichloroethylene (DDT) Dichlorodiphenyldichloroethylene (DDE) Dichlorodiphenyldiphenyldichloroethane (DDD)

Biodegradable A biodegradable pollutant is one that can be

broken down or neutralized by a living organism. The basis of a septic system is for bacteria to

ingest waste including paper products. Biodegradable waste can take as few as several

hours or as many as several years to degrade. Still fills up a landfill or a septic system though!

Slowly Degradable A pollutant that is slowly degradable takes

as long as several decades to breakdown. Some biodegradable plastics such as grocery

bags or food wrap, diapers, etc. Cotton and other organic materials sold as

consumable products.

Non-biodegradable Non-biodegradable refers to those

pollutants that cannot be broken down by natural processes. There are some chemical degradation

processes available. These wastes are filling up landfills and waste

processing plants.

Environmental Science has Environmental Science has limitations……………….limitations……………….

Cannot prove anything absolutely Cannot be totally free of bias Use of statistical tools Huge number of interacting variables

Complex systemsComplex systems Time lags – change in a system leads to other

changes after a delay – lung cancer Resistance to change – built in resistance –

political, economic Synergy-when two or more processes interact

so that the combined effect is greater Chaos – unpredictable behavior in a

system

Synergy and ChaosSynergy and Chaos

Synergy occurs when two or more processes interact so the combined effect is greater than the sum of the separate effects Grapefruit and Statins

Chaos occurs in a system when there is no pattern and it never repeats itself Noise versus Music

Implications for the environment – Implications for the environment – High waste societyHigh waste society

Implications for the environment – Implications for the environment – Low waste societyLow waste society

Gaia Hypothesis (1970)Gaia Hypothesis (1970) James Lovelock and Lynn

Marguilis