![Page 1: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/1.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 1Scientific Process
![Page 2: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/2.jpg)
Core Case Study: Carrying Out a Controlled Scientific Experiment
F. Herbert Bormann, Gene Likens, et al.: Hubbard Brook Experimental Forest in NH (U.S.)
Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site)
![Page 3: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/3.jpg)
The Effects of Deforestation on the Loss of Water and Soil Nutrients
Built v-shaped dams across the creeks at the bottom of forested valleys
Measured amounts of water and dissolved plant nutrients
![Page 4: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/4.jpg)
The Effects of Deforestation on the Loss of Water and Soil Nutrients
Investigators cut down all trees and shrubs in one valley
Sprayed area with herbicides to prevent regrowth
![Page 5: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/5.jpg)
The Effects of Deforestation on the Loss of Water and Soil Nutrients
Amount of water flowing out of the deforested valley increased by 30-40%• Eroded soil• Removed 6x more
nutrients from soil Conclusions????
![Page 6: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/6.jpg)
Scientists Use Reasoning, Imagination, and Creativity to Learn How Nature Works
Important scientific tools• Inductive reasoning – involves using
specific observations and measurements• Specific General
• Deductive reasoning – involves using logic to arrive at a specific conclusion based on a generalization or premise• General Specific
![Page 7: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/7.jpg)
Inductive or Deductive?
All birds have feathers. Eagles are birds. Eagles have feathers.
A meatball falls to the ground when dropped from a height of 10 feet. An olive falls to the ground when dropped from a height of 2 feet. All objects fall to the Earth’s surface when dropped.
Deductive
Inductive
![Page 8: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/8.jpg)
Nature of Science
An organized way of using evidence to learn about the natural world• Observations• Hypothesis• Experiment• Results• Conclusion• Repeating • Peer Review
![Page 9: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/9.jpg)
Nature of Science
Hypothesis• Proposed scientific explanation
for a set of observations
A good hypothesis must: 1. Be testable.2. Be a statement, not a question.3. Predict cause and effect.
If…then…
![Page 10: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/10.jpg)
Nature of Science
Null Hypothesis:• States that the variable will
have no effect on the outcome of the experiment
• Example: Light intensity has no effect on plant growth.
• Allows conclusions to be drawn that “reject” or “fail to reject” the null hypothesis
If…then…
![Page 11: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/11.jpg)
Able toChange
Variable
Every experiment measures two • Independent variable -- the variable that
the experimenter controls.• answers the question "What do I
change/control?"
• Dependent variable -- the variable the experimenter measures (results). • answers the question "What do I
observe/measure?"
![Page 12: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/12.jpg)
Scenario
A group of students is assigned a populations project in their APES class. They decide to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 13: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/13.jpg)
Independent Variable – What do I control ?
A group of students is assigned a populations project in their APES class. They decided to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 14: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/14.jpg)
Dependent Variable – What do I measure?
A group of students is assigned a populations project in their APES class. They decided to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 15: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/15.jpg)
Controlled Experiment
Experimental group - group that receives treatment in a controlled experiment.• Contains Independent Variable
Control group - group that does not receive treatment in a controlled experiment.• Does not contain Independent Variable
![Page 16: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/16.jpg)
Experimental Group– Which group has the IV? A group of students is assigned a
populations project in their APES class. They decided to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 17: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/17.jpg)
Control – Which group doesn’t have the IV? A group of students is assigned a
populations project in their APES class. They decided to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 18: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/18.jpg)
Able toChange
Variable
Levels – measure of your independent variable• Example: • Number of seeds in a pot• Number of fish in a fish bowl• Number of times that an action is repeated
![Page 19: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/19.jpg)
Levels – how is the IV measured? A group of students is assigned a
populations project in their APES class. They decided to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 20: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/20.jpg)
Controlled Experiment
Constant• What remains constant between
experimental groups Trials• Number of times you repeat an experiment• More tries = more reliable results
Sample size• The number of objects or events studied
![Page 21: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/21.jpg)
Constants – What do I keep the same? A group of students is assigned a
populations project in their APES class. They decided to determine the effect of sunlight on radish plant height. They set up 3 clay pots, each one containing 12 radish plants, 100g of potting soil, and given 25 mL of water daily. The pots are all 4 inches in diameter. One pot is placed in 24 hours darkness, one in 12 hours sunlight/12 hours darkness, and the last in 24 hours sunlight. After 5 days, they measure the height of all the plants in each pot.
![Page 22: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/22.jpg)
Not all experiments are created equal…
Frontier science – preliminary testing
Reliable science – well supported and studied experiments• High probability of
being true Unreliable –
unsupported via peer review
Critical Thinking Questions:• Was the experiment
controlled?• Have the data been
verified?• Have the results been
reproduced by other scientists?
• Are the investigators unbiased?
• Have the conclusions been verified by impartial peer review?
![Page 23: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/23.jpg)
Scientific Theories and Laws
Theory• Verified, credible
and widely accepted hypothesis
• Make future predictions
Law• Mathematical
description of what a theory explains
Paradigm Shift• Majority of
scientists in a field accept a new framework for theories and laws
![Page 24: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/24.jpg)
Your Turn!
Case of the Ivory Billed Woodpecker http://www.pbs.org/wgbh/nova/nature/ivor
y-billed-woodpecker.html
![Page 25: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/25.jpg)
The Case of the Ivory Billed Woodpecker
Case of the Ivory Billed Woodpecker http://www.pbs.org/wgbh/nova/nature/ivor
y-billed-woodpecker.html
![Page 26: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/26.jpg)
The Case of the Ivory Billed Woodpecker
![Page 27: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/27.jpg)
Wisconsin Fast Plants Laboratory Project
1. Make a list of questions you have about plants.• Be creative!
2. Suggested IV:• Fertilizer• Crowding• Acid (vinegar)• Soil• Glucose
![Page 28: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/28.jpg)
Your Turn: Wisconsin Fast Plant Project!
1. On your paper include the following information:
1. Question 2. Hypothesis3. Null Hypothesis4. Experimental Design
1. Independent and Dependent Variable2. Control and Experimental Groups3. Levels4. Constants5. Sample Size
5. Detailed Procedure
![Page 29: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/29.jpg)
Peer Review
Is the hypothesis testable, a statement, and does it predict a cause and effect relationship?
Will the data be quantitative rather than qualitative?
Are there any unaccounted for variables? If so, what are they?
Is the procedure logical? Any remaining questions or comments?
![Page 30: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/30.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 2Chemical Bonding
![Page 31: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/31.jpg)
MatterAny substance that: Occupies space Has mass Is made of atoms
![Page 32: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/32.jpg)
Some Forms of Matter Are More Useful than Others
Matter quality – measure of how useful a form of matter is to humans as a resource• Based on
availability and concentration
![Page 33: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/33.jpg)
Some Forms of Matter Are More Useful than Others
High-quality matter • highly concentrated• Near the Earth’s
surface• Great potential as a
resource
Low-quality matter• Not highly
concentrated• Located deep
underground or ocean
• Little potential for use
![Page 34: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/34.jpg)
We Cannot Create or Destroy Matter
Matter consumption• Matter is converted
from one form to another
Law of conservation of matter – matter cannot be created nor destroyedEverything we think we have thrown away remains
here with us in some form…
![Page 35: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/35.jpg)
Matter Consists of Elements and Compounds
Elements• Unique properties• Cannot be broken down chemically into
other substances• SPONCH
Compounds• Two or more different elements bonded
together in fixed proportions
![Page 36: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/36.jpg)
Organic Compounds Are the Chemicals of Life
Inorganic compounds
Organic compounds• Macromolecules: complex organic
molecules• Carbohydrates• Proteins• Nucleic acids• Lipids
![Page 37: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/37.jpg)
Atomic Composition
No unique substances in living things, just different amounts
“Same ingredients, different recipes.”
![Page 39: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/39.jpg)
![Page 40: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/40.jpg)
Example: Carbon
• Atomic Number = 6
• 6 Protons
• 6 Electrons
• Atomic Mass = 12
• 12 – 6 = 6
• 6 Neutrons
![Page 41: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/41.jpg)
Your Turn!
Atomic Mass #...
![Page 42: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/42.jpg)
ELECTRONEGATIVITY
The tendency of an atom to attract electrons to itself when it is bonded to another atom
![Page 44: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/44.jpg)
BONDING OPTIONSCOVALENT BOND By sharing electrons
(small difference in EN)
IONIC BOND By transferring electrons (producing ions)
(big difference in EN)
![Page 45: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/45.jpg)
Chemical Bonding
Atoms combine according to certain rules
• Rules determined by the number of electrons found in the outermost energy level
• First energy level = 2 electrons• Second energy level = 8 electrons• Third energy level = 8 electrons
![Page 46: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/46.jpg)
Chemical Bonding
![Page 47: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/47.jpg)
Covalent Bonds
Sharing of electrons• Electrons travel in
the orbitals of both atoms
Each atom fills out the outermost energy level
![Page 48: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/48.jpg)
Water: A Covalent Bond
![Page 49: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/49.jpg)
Ionic Bonds
Transfer of electrons
Ex. NaCl• Sodium has one
electron in outer shell Na +
• Chlorine has seven electrons in its outer shell Cl –
![Page 50: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/50.jpg)
Ionic Bond
Ion = charged particle• Anion = negatively charged• Cation = positively charged
Strong attraction between oppositely charged ions forms the ionic bond
![Page 51: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/51.jpg)
Ionic Bond
![Page 52: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/52.jpg)
Trick to Remember! If an atom GAINS electrons,
its overall charge becomes more negative.
If it LOSES electrons, its charge becomes more positive
![Page 53: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/53.jpg)
Your Turn!
Bonding Practice Covalent: Carbon and Chlorine Ionic: Sodium and Chlorine
![Page 54: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/54.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 3Water
![Page 55: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/55.jpg)
Why is it important?
Covers ¾ of Earth’s surface!• Most abundant compound in most
living things Exceptional substance with many
extraordinary qualities!
![Page 56: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/56.jpg)
Unusual Properties Determine characteristics of:
Atmosphere
Ocean
Land
![Page 57: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/57.jpg)
Water’s Structure…Simple?
Hydrogen• 1 electron…needs 2
Oxygen• 6 electrons (outer
shell)…needs 8 Covalent Bonding
![Page 58: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/58.jpg)
Polar Molecule
Charges are unevenly distributed• Partial positive• Partial negative
Electronegativites of atoms differ
![Page 59: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/59.jpg)
Electronegativity
Ele
ctro
neg
ativ
ity
![Page 60: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/60.jpg)
Hydrogen Bonds
Attraction between two different molecules
“weak” bond Not “real” bond b/c
no sharing or transferring of electrons • Ex: water, proteins, &
DNA
![Page 61: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/61.jpg)
How many hydrogen bonds can each water molecule form?
![Page 62: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/62.jpg)
As one hydrogen bond is broken another one forms
Each bond lasts trillionths of a second
Substantial percentage bonded to neighbor
![Page 63: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/63.jpg)
Cohesion
Attraction between molecules of the same substance
Causes molecules on the surface of water to be drawn inward• Why water forms
beads on smooth surfaces
• Why insects can walk on water
![Page 64: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/64.jpg)
Surface Tension
Result of cohesion How it “stretches or
resists breaking” Water molecules form
weak elastic membrane• Water to water • Water to air
![Page 65: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/65.jpg)
Adhesion
Attraction between molecules of different substances• Meniscus
Water to Water
Water to Glass
![Page 66: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/66.jpg)
Capillary Action
Forces that draw water out of the roots of a plant and up into its stems and leaves
Holds column of water together as it rises
Cohesion and adhesion
![Page 67: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/67.jpg)
Density
Less dense as a solid Hydrogen bonds stay
connected• less energy in system
so bonds don’t break More space occurs
between water molecules
![Page 68: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/68.jpg)
Solutions
All components are evenly distributed throughout• Solute – substance that
is dissolved• Solvent – the substance
in which the solute dissolves
Due to water’s polarity• Can dissolve ionic
compounds and other polar molecules
![Page 69: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/69.jpg)
Solubility
Water surrounds the charged ends and separates the molecules
![Page 70: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/70.jpg)
Suspensions
Mixtures of water and nondissolved material• Materials don’t
dissolve but separate into pieces so small that they do not settle out
Example• Blood
![Page 71: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/71.jpg)
Your Turn!
Water Property Lab
![Page 72: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/72.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 4Isotopes and Nuclear
Reactions
![Page 73: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/73.jpg)
Isotopes
Number of neutrons can vary from one atom of an element to another• Changes atomic mass, not atomic
number Atomic number NEVER changes
![Page 74: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/74.jpg)
Isotopes
H = hydrogen1
1
H = deuterium
H = tritium
1
2
1
3
Identified by mass #
![Page 75: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/75.jpg)
Isotopes
Isotopes have SAME number of protons but DIFFERENT numbers of neutrons• Heavier• Behave identical in chemical reactions
Same # electrons = same chemical properties
![Page 76: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/76.jpg)
Radioactive Isotopes
Diagnose and treat diseases• Cardiovascular
disease• Cancer radiation
Sterilize foods• Kill bacteria • Preserve food
Measure the ages of certain rocks• Fossils
![Page 77: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/77.jpg)
Matter Undergoes Physical, Chemical, and Nuclear Changes
Nuclear change – changes in the nuclei of atoms• Nuclear fission –
nucleus splits and releases neutrons plus energy
![Page 78: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/78.jpg)
Matter Undergoes Physical, Chemical, and Nuclear Changes
Nuclear change – changes in the nuclei of atoms• Nuclear fission –
nucleus splits and releases neutrons plus energy
• Nuclear fusion – two nuclei fuse together and release energy
![Page 79: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/79.jpg)
Nuclear Power 6:51
![Page 80: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/80.jpg)
Light-Water-Moderated and -Cooled Nuclear Power Plant with Water Reactor
![Page 81: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/81.jpg)
After 3 or 4 Years in a Reactor, Spent Fuel Rods Are Removed and Stored in Water
![Page 82: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/82.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 5pH
![Page 83: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/83.jpg)
What do vinegar, lemons, and orange juice have in common?
![Page 84: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/84.jpg)
Characteristics of Acids
Taste Sour React with metals Often produce
hydrogen gas Can burn your skin
![Page 85: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/85.jpg)
What do milk, Comet, and Tums have in common?
![Page 86: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/86.jpg)
Characteristics of Bases
Taste Bitter Feel Slippery Neutralize Acids• Antacids
Dissolve grease
![Page 87: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/87.jpg)
But, what exactly are acids and
bases?
![Page 88: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/88.jpg)
Substance that ionizes in water to give hydrogen ions (H+)
Acid
![Page 89: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/89.jpg)
Examples of Acids
HCl H2SO4
HNO3
HF Juices
![Page 90: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/90.jpg)
Substance that ionizes in water to give hydroxide ions (OH-)
Base
![Page 91: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/91.jpg)
Examples of Bases
NaOH Ca(OH)2
KOH Soap, Ammonia,
Baking Soda
![Page 92: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/92.jpg)
The pH Scale
Measurement system that indicates the concentration of H+ ions in solution.• The pH scale ranges from 0 to
14.
![Page 93: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/93.jpg)
The pH Scale
pH = “power of hydrogen”• Each step increases by a power
of ten
![Page 94: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/94.jpg)
pH Scale
![Page 95: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/95.jpg)
pH Calculations
Remember: For every one-increment change in pH, the ions change by a factor of 10.
Example: What is the difference in H+ concentration between pH 6 and pH 4?• pH 6 – pH 4 = pH 2• H+ is 100 times more concentrated in the
pH 4 solution
![Page 96: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/96.jpg)
pH Calculations
Remember: Concentration of H+ and OH- always equals 10-14 M or pH 14
Example: [H+] = 10-6 M• pH is 6: weak acid• [OH-] = 10-8 M
![Page 97: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/97.jpg)
pH and Water
Why does water have a pH of 7?• Hydronium ions = hydroxide ions • (H+) = (OH-)
H20 H+ + OH-
![Page 98: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/98.jpg)
Interesting fact…
Water can act as an acid or a base!!!
![Page 99: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/99.jpg)
Interesting fact…
Amphoteric -substance that can act as either an acid or a base.
![Page 100: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/100.jpg)
Your Turn!
Review of pH Calculations
![Page 101: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/101.jpg)
pH Scale
![Page 102: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/102.jpg)
Your Turn…pH of natural substances
Substances:• Soil• Freshwater• Saltwater• Rainwater
Tools:• Soil – capsules• Water (use 2 of the following) - pH meter,
litmus paper, or microkit
![Page 103: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/103.jpg)
Your Turn…pH of natural substances
Capsules
pH Meter Litmus Paper
Microkit
Soil
Freshwater
Saltwater
Rainwater
![Page 104: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/104.jpg)
Buffers
Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.
![Page 105: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/105.jpg)
Buffers are working
while you exercise!
![Page 106: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/106.jpg)
Ocean pH
Surface water pH ranges from 8.0 to 8.3• Average 8.1
Ocean water combines with CO2
Forms weak Carbonic Acid
H20 + CO2 H2CO3 H+ + HCO3-
![Page 107: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/107.jpg)
Ocean pH
Average pH 8.1• BASIC?
Carbonic Acid?
Why is the ocean pH slightly basic when CO2 (an acid) is
added?
![Page 108: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/108.jpg)
Carbonate Buffering
Keeps ocean pH about same (8.1) pH too high, carbonic acid releases H+
pH too low, bicarbonate combines with H+
H2CO3 H+ + HCO3-
HCO3- + H+ H2CO3
![Page 109: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/109.jpg)
Carbonate Buffering
Marine organisms die and sink into deep ocean• Calcium carbonate in shell neutralizes acid
through buffering
CaCO3 CO3- + H+
HCO3- + H+ H2CO3
![Page 110: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/110.jpg)
Carbonate Buffering
Dead mollusks are the antacids of the sea!
![Page 111: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/111.jpg)
Carbonate buffering
![Page 112: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/112.jpg)
![Page 113: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/113.jpg)
Recent Decrease in Ocean Acidity
Excess carbon dioxide in atmosphere• 33% CO2 released by burning fossil fuels
ends up in ocean Overwhelming oceans natural ability to
buffer itself• pH has decreased 0.1 since preindustrial
times
![Page 114: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/114.jpg)
Recent Decrease in Ocean Acidity
More difficult for certain marine creatures to build hard parts out of calcium carbonate• Plankton• Corals
Alter food chain of ocean!
![Page 115: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/115.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 6Thermodynamics
![Page 116: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/116.jpg)
Energy Comes in Many Forms
Kinetic energy - energy of motion• Mass and velocity!• Electromagnetic
radiation of waves• Short = greater
energy
![Page 117: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/117.jpg)
Kinetic energy
Atoms and molecules in any gas, liquid, or solid are always in motion
• Vibrate around average position
Kinetic Energy = ½ (mass)(velocity)2
![Page 118: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/118.jpg)
Temperature
Measure of the average kinetic energy of the atoms and molecules in the substance
Measured in degrees• Celsius• Fahrenheit• Kelvin
![Page 119: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/119.jpg)
Heat
Measure of total kinetic energy of the atoms and molecules in a substance
Measured in calories
![Page 120: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/120.jpg)
Calorie
Amount of heat needed to raise the temperature of 1g of water by 1oC
1 food Calorie (1 kilocalorie) = 1000 calories
![Page 121: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/121.jpg)
What’s the difference?
Which has greater average Kinetic Energy?• Higher Temperature?
Which has greater total Kinetic Energy?• More Heat?
![Page 122: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/122.jpg)
Energy Comes in Many Forms
Potential energy - energy of position• Stored energy; can
be changed into kinetic energy
• Examples: rock held in hand, unlit match, gasoline
![Page 123: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/123.jpg)
Some Types of Energy Are More Useful Than Others
Energy quality - measure of an energy source’s capacity to do useful work
High-quality energy – concentrated energy that has a high capacity to do useful work• High-temperature heat• Concentrated sunlight• High velocity wind
![Page 124: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/124.jpg)
Some Types of Energy Are More Useful Than Others
Energy quality - measure of an energy source’s capacity to do useful work
Low-quality energy – energy that is dispersed and has little capacity to do useful work• Low temperatures
![Page 125: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/125.jpg)
Energy Changes Are Governed by Two Scientific Laws
First Law of Thermodynamics• Energy input always equals energy output
Second Law of Thermodynamics• Energy always goes from a more useful to a
less useful form when it changes from one form to another• Decreased energy efficiency
![Page 126: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/126.jpg)
Life application
94% of the money you spend for gasoline is not used to transport you anywhere!
![Page 127: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/127.jpg)
The Second Law of Thermodynamics in Living Systems
![Page 128: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/128.jpg)
Your Turn!
Potential vs. Kinetic worksheet
![Page 129: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/129.jpg)
Science, Matter, Energy, and Systems
Chapter 2 – Part 7Systems
![Page 130: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/130.jpg)
Systems Have Inputs, Flows, and Outputs
System – set of components that function and interact in some regular way• Inputs from the
environment• Flows,
throughputs• Outputs
![Page 131: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/131.jpg)
Systems Respond to Change through Feedback Loops
Positive feedback loop - causes a system to change in the same direction
![Page 132: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/132.jpg)
Systems Respond to Change through Feedback Loops
Negative feedback loop – causes a system to change in the opposite direction from which it is moving• Opposing process
Can promote sustainability!• Aluminum mining
can recycling
![Page 133: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/133.jpg)
Video Clip – Planet Earth Forests
Cicada Life Cycle
21:00-26:00
![Page 134: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/134.jpg)
Time Delays Can Allow a System to Reach a Tipping Point
Time delays vary• Between the input
of a feedback stimulus and the response to it
• Example: Planting trees
Tipping point, threshold level• Causes a shift in
the behavior of a system
![Page 135: Science, Matter, Energy, and Systems Chapter 2 – Part 1 Scientific Process](https://reader036.vdocuments.site/reader036/viewer/2022062423/56649cbb5503460f949837b2/html5/thumbnails/135.jpg)
System Effects Can Be Amplified through Synergy
Synergistic interaction – two or more processes interact so that the combine effect is greater than the sum of their separate effects• Helpful• E.g., campaign vs. individual persuasion
• Harmful• E.g., Smoking and inhaling asbestos
particles