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APES Chapter #3. Science, System, Matter and Energy . Nature of Science. Science- an organized way of using evidence to learn about the natural world Observations Hypothesis Experiment Results Conclusion. Scientific Method Observations and Hypothesis. 1.Observations/Questions

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Apes chapter 3

APES Chapter #3

Science, System, Matter and Energy


Nature of science

Nature of Science

  • Science- an organized way of using evidence to learn about the natural world

    • Observations

    • Hypothesis

    • Experiment

    • Results

    • Conclusion


Apes chapter 3

Scientific MethodObservations and Hypothesis

  • 1.Observations/Questions

    • What you see

    • Inferences-logical interpretations of what you see.

    • Questions then arise…….

  • 2.Hypothesis-scientific and testable explanation for observations

  • “If……then……”


Scientific method experimental procedure

Scientific MethodExperimental Procedure

  • 3.Experimental procedure- test the hypothesis

  • Must be controlled, reproducible

Testing effects of

only one variable

(factor in experiment

that is subject to

change)

Other scientists

need to be able to

reproduce and

prove valid.


Scientific method experimental procedure1

Scientific MethodExperimental Procedure

  • Subjects you are testing are split into groups:

    • Experimental Group-given the experimental factor

    • Control Group:-what you’re comparing experimental group to.

Experimental Group

Fertilizer

Control Group

No Fertilizer


Scientific method experimental procedure2

Scientific MethodExperimental Procedure

  • Testing ONE variable while keeping others the same

    • Independent (manipulated) variable- factor in experiment that’s purposely changed—????

    • Dependent (responding) variable —factor that a scientist observes for responses (changes) in—????


Apes chapter 3

Scientific MethodResults and Conclusion

  • 4. Results

    • Record data—tables, graphs

    • Qualitative data- physical traits (qualities) described

    • Quantitative data- measurements (quantities)

  • 5.Conclusions

    • Hypothesis is either supported or rejected. NEVER “PROVEN!”

    • Can be partly true

    • Findings always useful!!!


Scientific method hypothesis vs theory

Scientific MethodHypothesis vs. Theory

  • Hypothesis- educated, testable explanation for an observation

  • Theory

    • Verified, credible and widely accepted hypothesis

    • Make future predictions

  • Law- mathematical description of what a theory explains


Apes chapter 3

Models and Behavior of SystemsSystem

  • Scientists determine the behavior of a system by developing a model of it in regards to matter and energy

  • Set of components that function and interact in regular, understandable way

Throughputs(rates of flow)

Outputs(to environment)

Inputs(from environment)

Energy

Heat

Human Body(inputs may be stored for different lengths of time)

Ideas and actions

Information

Waste and pollution

Matter


Models and behavior of systems feedback loops

Models and Behavior of SystemsFeedback Loops

  • Feedback loops are found in a system

  • Output fed back into system leads to changes

    • Positive feedback- AMPLIFICATION

      • i.e. global warming

    • Negative feedback- CORRECTIVE

      • System changes in opposite direction

      • i.e. thermostat in house

      • crime and punishment


Models and behavior of systems time delays and synergy

Models and Behavior of SystemsTime Delays and Synergy

  • Time delays -delay b/t input and output

    • Allows problems to build slowly so corrective action may come too late

    • i.e. smoking and population

  • Synergy- 2 or more processes interact so their combined effect is > than the sum of separate effects

    • i.e. drugs and alcohol, people picking up object


Matter atoms

MatterAtoms

  • Matter-anything that has mass and takes up space

  • Atom--basic unit of matter

    • Protons—positive, nucleus

    • Neutrons—neutral, nucleus

    • Electrons—negative, orbits


Matter parts of atoms

MatterParts of Atoms

  • Protons and Neutrons

    • Together make up an atom’s atomic mass.

  • Electrons

    • 1/1840 of the mass of p’s and n’s

    • Moving in orbitals surrounding the nucleus

    • Responsible for chemical properties of atoms (how they react)

    • Atoms--Something to Think About!


Matter elements

MatterElements

  • Element-pure substance that consists of just one type of atom

  • 114 in the periodic table

    • Atoms have a one or two letter symbol

    • Atomic number

      • Unique to that element

      • #p’s-- and b/c normally atoms

        are uncharged also = # e’s

    • Atomic mass

      • How much mass an atom has

      • #p’s + #n’s

6

C

Carbon

12.011


Apes chapter 3

MatterIsotopes

6

Isotopes-atoms of the same element with different # of neutrons

Atomic number same, atomic mass different

Isotopes of Carbon

Nonradioactive carbon-13

Radioactive carbon-14

Nonradioactive carbon-12

6 electrons

6 protons

6 neutrons

6 electrons

6 protons

7 neutrons

6 electrons

6 protons

8 neutrons


Matter radioactive isotopes

MatterRadioactive Isotopes

  • Radioactive isotopes- atoms with unstable nuclei

    • Break down at constant rate and can give off dangerous radiation (type of energy)

    • Beneficial uses:

      • C-14 dating can help geologists date fossils

      • Cancer treatment

      • U-235 in nuclear reactors


Apes chapter 3

MatterBonding

  • Bonding- atoms gain, lose, or share e’s to be stable

  • Compound- formed by chemical combination of 2 or more elements

  • Bond formation involves outermost e’s

  • Two types of bonds

    • Ionic

    • Covalent


Apes chapter 3

  • Chemical Bonds

  • Ionic bonds

    • Ionic bond -one or more e’ are transferred

    • Results in formation of ions, or charged atoms that attract to form an ionic compound

Chloride ion (Cl-)

Sodium atom (Na)

Chlorine atom (Cl)

Sodium ion (Na+)

Transfer

of electron

Protons +11

Electrons -11

Charge 0

Protons +17

Electrons -17

Charge 0

Protons +11

Electrons -10

Charge +1

Protons +17

Electrons -18

Charge -1


Chemical bonds covalent bonds

Chemical BondsCovalent Bonds

  • Covalent bonds- formed by atoms sharing valence electrons

    • Stronger than ionic bonds

    • Molecule--forms when atoms are joined in a covalent bond


Compounds

Compounds

  • Organic- contain C-C bonds

  • Can also have H, O, P, S, N and others

  • Natural or synthetic

  • Inorganic- don’t have C-C or C-H covalent bonds

  • NaCl, H2O

C

C


Organic compounds

Organic Compounds

  • Some simple organic molecules can link up, forming C—C bonds- polymerization

    • Amino acids Proteins (meats, enzymes)

    • Fatty Acids and glycerol Lipids (fats, oils)

    • Sugars  Carbohydrates (sugar, starches)

    • Nucleotides Nucleic acids (DNA or RNA)


Inorganic compounds

Inorganic Compounds

  • No C-C bonds

  • Earth’s crust is mostly inorganic minerals and rock

  • Various combinations of only eight elements make up the bulk of most minerals.


Four states of matter

Four States of Matter

  • Differ in spacing and orderliness of atoms, ions or molecules

    • Solid

    • Liquid

    • Gas

    • Plasma

      • Most abundant of all states of matter!

      • Forms when enough energy applied to strip away e’, so it’s a mixture of ions and e’

      • Natural forms: sun, stars, lightning and flame

      • Artificial forms: TV, neon signs


Matter quality

Matter Quality

  • High quality

    • Easily accessible

    • High concentration

    • Great potential for use as resource

  • Low quality

    • Deep underground or difficult to

      collect

    • Low concentration

    • Low potential as a resource


Apes chapter 3

High Quality

Low Quality

Gas

Solid

Salt

Solution of salt in water

Coal

Coal-fired power

plant emissions

Gasoline

Automobile emissions

Aluminum can

Aluminum ore


Law of conservation of matter

Law of Conservation of Matter

  • Physical changes in matter

    • Molecules organized differently but no change in chemical composition

    • Cutting foil, melting water

  • Chemical changes

    • Bonds made or broken

    • Burning coal, rusting


Apes chapter 3

ChemicalChanges

Reactant(s)

Product(s)

carbon + oxygen

carbon dioxide+ energy

C + O2

CO2+ energy

O

C

O

C

O

+ energy

O

black solid

colorless gas

colorless gas


Law of conservation of matter1

Law of Conservation of Matter

  • Law of Conservation of Matter- physical or chemical changes can’t create or destroy the atoms involved. They’re just rearranged

  • Chemical equations must be balanced

  • No “away”!!!! -Law tells us there will always be wastes, pollutants, and toxins


Apes chapter 3

Toxicology

Toxicology -the study of the adverse effects of chemicals or pollutants on living organisms’ health, specifically humans.

Toxicity -a measure of how harmful a substance is and it depends on:-Amount of a potentially harmful substance that is ingested, inhaled, or absorbed through the skin is called the dose-Frequency of exposure-Who is exposed (adult or child)-How well the body’s detoxification system (liver, kidneys, etc.) work

© Brooks/Cole Publishing Company / ITP


Apes chapter 3

Toxicology

The resulting type and amount of damage to health arecalled the response

Two types of responses:

  • Acute- immediate or rapid harmful reaction (dizziness, rash, death)

  • Chronic- permanent or long–lasting consequence (asthma, kidney damage, heart disease)


Toxicology factors

Toxicology Factors

  • Six major characteristics of a substance determines its toxicity:

    • 1. Concentration

      • 1ppm= 1 part pollutant per million parts of gas, solid or liquid it is in

      • Can ↓ pollutant concentration by dumping in larger volume, but there are limits

    • 2. Solubility

      • Water-soluble- move through the environment and get in the water supply

      • Fat-soluble- penetrate cell membranes and accumulate in body tissue


Apes chapter 3

Toxicology Factors

  • 3. Persistence

    • Some chemicals are resistant to breakdown so have long-lasting harmful effects

    • Degradable (nonpersistent)—broken down by natural, physical, chemical or biological processes

    • Biodegradable—broken down by living organisms

    • Slowly degradable (persistent)

      • Decades

      • Plastics, DDT

    • Nondegrading—lead, mercury, arsenic


Apes chapter 3

Toxicology Factors

  • 4. Bioaccumulation results when the concentration of a chemical in tissues of an organism is higher than would normally be expected.

  • 5. Biomagnification involves magnification of concentrations as they pass through the food chains and webs.

© Brooks/Cole Publishing Company / ITP


Apes chapter 3

Toxicology Factors

  • 6. Chemical Interactions

    • Antagonistic interactions reduce harmful effects

      • Vitamin A, D and E apparently reduce some cancer-causing chemicals

    • Synergistic interactions multiplies harmful effects

      • Asbestos workers have a 20-fold increased chance of getting lung cancer, but if they smoke they have a 400-fold increase


Apes chapter 3

Determining Toxicity

  • Determining toxicity:

    • Case reports (usually to physicians)

    • Epidemiology- studies of populations exposed

    • Laboratory investigations (usually with test animals)

      • LD50 (median lethal dose) -amt of a chemical that kills 50% of animals (rats) in a test population (60–200 animals) in 2 weeks

      • A poison is legally defined as a chemical that has an LD50≤50 mg chemical/kg body weight

  • ***Higher LD50, less toxic the substance is


Toxicity

Toxicity

ToxicityLD50Lethal DoseExamples

Super < 0.01less than 1 drop dioxin, botulism

mushrooms

Extreme <5less than 7 drops heroin, nicotine

Very 5-507 drops to 1 tsp. morphine, codeine

Toxic50-5001 tsp. DDT, H2SO4, Caffeine

Moderate 500-5K1 oz.-1 pt. aspirin, wood alcohol

Slightly5K-15K 1 pt. ethyl alcohol, soaps

Non-Toxic>15K>1qt. water, table sugar

***Higher LD50, less toxic the substance is

(LD50 measured in mg/kg of body weight)


Apes chapter 3

Dose–Response Curves

Dose–response curves- show the adverse effects of various doses of a toxic agent on a test population by plotting harmful effect as a function of dose.

The left dose–response curve shows increasing harmful effects with dose, and no dose is considered safe.

The right example has a threshold, such that low doses are considered safe.

© Brooks/Cole Publishing Company / ITP


Apes chapter 3

Toxicity

  • Why so little is known of toxicity

    • Only 10% of at least 75,000 commercial chemicals have been screened

    • ~2% determined to be carcinogen, teratogen or mutagen

    • >1000 new synthetic chemicals added per year

    • >99.5% of US commercial chemicals are NOT regulated


Apes chapter 3

Chemical Hazards

  • What are toxic vs. hazardous chemicals?

    • Toxic (poisonous) chemicals- substances that are fatal to over 50% of test animals (LD50) at given concentrations

    • Hazardous chemicals- cause harm by

      • Flammable or explosive (e.g., gasoline)

      • Irritating or damaging the skin or lungs (e.g., strong acids or alkalines such as oven cleaners)

      • Interfering with or preventing oxygen uptake and distribution (e.g., carbon monoxide, CO)

      • Inducing allergic reactions

© Brooks/Cole Publishing Company / ITP


Apes chapter 3

Hazardous chemicals

  • Mutagens- cause random mutations, or changes in the DNA

  • Teratogens- cause birth defects

    • e.g., PCBs, steroid hormones, heavy metals, rubella, mercury in water, fetal alcohol syndrome and crack babies

  • Carcinogens- cause cancer

    • over 100 types of cancer (depending on cells involved)

    • e.g., cigarette smoke.

  • Hormone disrupters

© Brooks/Cole Publishing Company / ITP


Apes chapter 3

Hormone Disrupters

Hormones -molecules that act as messengers in the endocrine system to regulate reproduction, growth and development.

Hormone disrupters (mimics and blockers), attach to receptors and disrupt/alter development.

© Brooks/Cole Publishing Company / ITP


Apes chapter 3

Hormone Disrupters

  • 51 chemicals, many widely used, have been shown to be hormone disrupters on wildlife, laboratory animals and humans

    • i.e. dioxins, certain PCBs, various chemicals in plastics, some pesticides, lead and mercury

  • 1997 study shows that sperm count of men in U.S. and Europe has declined 50%.

© Brooks/Cole Publishing Company / ITP


Energy

Energy

  • Energy- capacity to do work and transfer heat

  • Measured in calories = amt of heat required to raise the temp of 1.0g of water 1oC

  • Work is movement of matter (pump gas through pipe, move book)


Energy1

Energy

  • Two types

    • Kinetic

      • Energy in motion

      • Possessed by matter b/c of its mass and speed (velocity)

    • Potential

      • Stored energy

      • Potential to be changed into kinetic energy

      • Rock in hand, unlit match, energy stored in bonds of foodstuff, water behind dam


Apes chapter 3

EnergyElectromagnetic radiation

Sun

High energy, short

wavelength

Low energy, long

wavelength

Nonionizing radiation

Ionizing radiation

Visible

Cosmic

rays

Far

ultraviolet

waves

Near

ultraviolet

waves

Near

infrared

waves

Far

infrared

waves

Gamma

rays

TV

waves

Radio

waves

X rays

Microwaves

10-14

10-12

10-8

10-7

10-6

10-5

10-3

10-2

10-1

1

  • Electromagnetic radiation (EM)- energy traveling in waves as

  • a result of changing electric and magnetic fields

  • Different forms with different wavelengths and energy content

  • Electromagnetic Radiation Movie


Energy electromagnetic radiation

EnergyElectromagnetic radiation

  • Two types of EM radiation

    • Ionizing EM radiation

      • High energyknock e’s from atoms and change them to + ions

      • e’s and ions disrupt living cells-cancer

    • Non-ionizing EM radiation

      • Low energy Not highly reactive or as dangerous.

      • Visible light-- makes up most of the spectrum of EM radiation from the sun.


Energy heat

EnergyHeat

  • Heat- total kinetic energy of all moving atoms, ions or molecules

  • Temperature—average speed of motion of the atoms, ions or molecules in matter

  • Atoms move faster when heated

  • Heat energy flows hot  cold

  • Hot air/water less dense due to energy so rises.


Energy quality

Energy Quality

  • Energy quality- measure of energy source’s ability to do useful work

    • High quality

      • Concentrated

      • Can perform much useful work

      • Chemical energy in coal and gas, sunlight

    • Low quality

      • Dispersed

      • Little ability to do work

      • Heat in atmosphere or heat in oceans


Energy laws 1 st law of thermodynamics

Energy Laws1st Law of Thermodynamics

  • 1st law of thermodynamics (Law of conservation of energy)

    • In all physical and chemical changes, energy is not created or destroyed, but changes form

    • Total energy of system remains constant


Energy laws 2 nd law of thermodynamics

Energy Laws2nd Law of Thermodynamics

  • 2nd Law of Thermodynamics (Law of disorder)

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

    • Light bulb---95% lost as waste heat

    • Energy stored in food---most lost as waste heat

    • **We can never recycle or reuse high-quality energy to perform useful work


Apes chapter 3

Mechanical

energy

(moving,

thinking,

living)

Chemical

energy

(food)

Chemical

energy

(photosynthesis)

Solar

energy

Waste

heat

Waste

heat

Waste

heat

Waste

heat


Nuclear changes

Nuclear Changes

  • Matter can undergo physical, chemical OR nuclear changes

  • Nuclear change--nucleus of certain isotopes spontaneously change or are made to change into nuclei of different isotopes

  • Matter  Energy

  • 3 types of nuclear change

    • Radioactive decay

    • Nuclear fission

    • Nuclear fusion


Nuclear changes radioactive decay

Nuclear ChangesRadioactive Decay

  • Radioactive isotopes with unstable nuclei decay

  • Particles and/or damaging ionizing radiation, emitted until nuclei stable and not radioactive

    • Gamma rays

    • Genetic damage to DNA

    • Somatic damage to tissues


Nuclear changes radioactive decay1

Nuclear ChangesRadioactive Decay

  • Radioactive isotopes decay at a characteristic fixed rate called a half-life (t1/2)

    • Time for half the nuclei in a sample to decay

    • Can’t be changed due to T, P, or chemical rxns

    • Used to estimate time a sample of radioisotope must be stored safely before it decays to a safe level half-life X 10


Apes chapter 3

Table 3-1 Half-Lives of Selected Radioisotopes

Isotope

Potassium-42

Iodine-131

Cobalt-60

Hydrogen-3 (tritium)

Strontium-90

Carbon-14

Plutonium-239

Uranium-235

Uranium-238

Radiation Half-Life

12.4 hours

8 days

5.27 years

12.5 years

28 years

5,370 years

24,000 years

710 million years

4.5 billion years

Emitted

Alpha, beta

Beta, gamma

Beta, gamma

Beta

Beta

Beta

Alpha, gamma

Alpha, gamma

Alpha, gamma


Nuclear changes nuclear fission

Nuclear ChangesNuclear Fission

  • Fission—splitting of nuclei

    • Nuclei of isotopes with large masses split into lighter nuclei when struck by neutrons

    • Release energy and more neutrons setting off a chain reaction

    • Atomic bomb and nuclear power plants


Apes chapter 3

Fission fragment

n

n

Energy

n

n

Uranium-235

nucleus

Unstable

nucleus

Fission fragment

Energy


Apes chapter 3

235

92

U

n

92

36

Kr

235

92

n

U

n

235

92

U

n

141

56

Ba

92

36

Kr

n

92

36

Kr

n

n

n

n

235

92

n

U

141

56

Ba

92

36

Kr

n

141

56

Ba

235

92

U

n

235

92

U

n

141

56

Ba

235

92

U


Nuclear changes nuclear fusion

Nuclear ChangesNuclear Fusion

  • Fusion—joining of nuclei

    • Isotopes of light elements are forced together at high T’s until they fuse into a heavier nucleus

      • Harder to accomplish than fission, but releases more energy

      • Fusion of H nuclei to form He nuclei is a source of energy for sun and stars

      • H bombs


Apes chapter 3

Fuel

Reaction Conditions

Products

D-T Fusion

Neutron

+

Hydrogen-2 or

deuterium nucleus

Energy

+

+

+

+

+

100 million ˚C

Helium-4

nucleus

Hydrogen-3 or

tritium nucleus

+

Proton

Neutron


Matter and energy laws environmental problems

Matter and Energy LawsEnvironmental Problems

  • Law of conservation of matter and 1st and 2nd law of thermodynamics together mean individual resource use adds waste matter and heat to the environment

  • Different types of economic systems

    • High-throughput, high waste economies

    • Matter-recycling-and-reuse economy

    • Low-throughput economy


Matter and energy laws environmental problems high throughput economy

Matter and Energy LawsEnvironmental ProblemsHigh-throughput Economy

  • Developed countries with ever increasing growth

  • Increased one-way flow of matter through systems and out to planetary “sinks”--air, water, soil, and organisms

    • Pollutants and wastes accumulate

    • Output will exceed environment’s capacity to dilute and degrade waste matter and absorb heat

  • UNSUSTAINABLE!


Matter and energy laws environmental problems low throughput economy

Matter and Energy LawsEnvironmental ProblemsLow-Throughput Economy

  • Decrease matter and energy flow

  • Don’t waste matter and energy resources

  • Recycle and reuse

  • Stabilize population


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