LIVING IN THE ENVIRONMENT 17 TH MILLER/SPOOLMAN CHAPTER 2 Science, Matter, Energy, and Systems With additional information from Friedland/Relyea, Environmental Science for AP, 2012

Core Case Study: A Story About a Forest Hubbard Brook Experimental Forest in New Hampshire Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site) Stripped site: 30-40% more runoff More dissolved nutrients More soil erosion

Characteristics of Science…and Scientists Curiosity Skepticism Reproducibility Peer review Openness to new ideas Critical thinking Creativity

Scientific Theories and Laws Are the Most Important Results of Science Scientific theory – proposed explanation Widely tested Supported by extensive evidence Accepted by most scientists Subject to change Ex: Theory of Evolution by Natural Selection Scientific law, law of nature – describes a truth valid throughout the universe Accepted as fact (for now) Ex: Law of Conservation of Energy

Collecting Data Replication- repeating sets of measurements times Sample size- #of times the measurement is replicated. Accuracy- how close a measured value is to the actual or true value. ((ex: extrapolating for a population estimate) Precision- how close to one another the repeated measurements are. Uncertainty- how much the measure differs from the true value.

Accuracy- how close a measured value is to the actual or true value. Precision- how close to one another the repeated measurements are.

Interpreting Results Analysis of data involves two types of reasoning: Inductive reasoning- the process of making general statements from specific facts or examples. Deductive reasoning- the process of applying a general statement to specific facts or situations.

Example of Deductive Reasoning Every day, I leave for work in my car at eight o’clock. Every day, the drive to work takes 45 minutes I arrive to work on time. Therefore, if I leave for work at eight o’clock today, I will be on time. The deductive statement above is a perfect logical statement, but it does rely on the initial premise being correct. This is why any hypothesis can never be completely proved, because there is always the possibility for the initial premise to be wrong.

Example of Inductive Reasoning Inductive reasoning works the opposite way, moving from specific observations to broader generalizations and theories. This is sometimes called a “bottom up” approach. The researcher begins with specific observations and measures, begins to then detect patterns and regularities, formulate some tentative hypotheses to explore, and finally ends up developing some general conclusions or theories. Ads Have You Written A Book? Get Your Manuscript Published Now. Request Your Free Publishing Guide. Aqua Mix Grout Colorant Change the color of your grout Match Laticrete Mapei Custom colors An example of inductive reasoning can be seen in this set of statements: Today, I left for work at eight o’clock and I arrived on time. Therefore, every day that I leave the house at eight o’clock, I will arrive to work on time. While inductive reasoning is commonly used in science, it is not always logically valid because it is not always accurate to assume that a general principle is correct. In the example above, perhaps ‘today’ is a weekend with less traffic, so if you left the house at eight o’clock on a Monday, it would take longer and you would be late for work. It is illogical to assume an entire premise just because one specific data set seems to suggest it.

pH Scale Supplement 5, Figure 4

Some Forms of Matter Are More Useful than Others High-quality matter Highly concentrated Near earth’s surface High potential as a resource Low-quality matter Not highly concentrated Deep underground or widely dispersed Low potential as a resource

Examples of Differences in Matter Quality Fig. 2-8, p. 42

2-3 What Happens When Matter Undergoes Change? Concept 2-3 Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed (the law of conservation of matter).

Matter Undergoes Physical, Chemical, and Nuclear Changes Physical change No change in chemical composition Chemical change, chemical reaction Change in chemical composition Reactants and products Nuclear change Natural radioactive decay Radioisotopes: unstable Nuclear fission Nuclear fusion

Types of Nuclear Changes Fig. 2-9, p. 43

2-4 What is Energy and What Happens When It Undergoes Change? Forms of Energy Chemical energy- potential stored in chemical bonds. Temperature- the measure of the average kinetic energy of a substance.

Energy Comes in Many Forms (1) Kinetic energy Energy of motion Flowing water Wind Heat Transferred by radiation, conduction, or convection Electromagnetic radiation Potential energy Stored energy Can be changed into kinetic energy

Fig. 2-11, p. 45 Visible light Gamma rays X rays Shorter wavelengths and higher energy Longer wavelengths and lower energy UV radiation Infrared radiation MicrowavesTV, Radio waves Wavelengths (not to scale) NanometersMicrometersCentimetersMeters The Electromagnetic Spectrum

Energy Comes in Many Forms (2) Sun provides 99% of earth’s energy Warms earth to comfortable temperature Plant photosynthesis Winds Hydropower Biomass Fossil fuels: oil, coal, natural gas

Some Types of Energy Are More Useful Than Others High-quality energy High capacity to do work Concentrated High-temperature heat Strong winds Fossil fuels Low-quality energy Low capacity to do work Dispersed

Energy Changes Are Governed by Two Scientific Laws First Law of Thermodynamics Law of conservation of energy Energy is neither created nor destroyed in physical and chemical changes Second Law of Thermodynamics Energy always goes from a more useful to a less useful form when it changes from one form to another Light bulbs and combustion engines are very inefficient: produce wasted heat

First law of thermodynamics Energy is neither created or destroyed. You can ’ t get something from nothing.

Second Law of Thermodynamics Energy quality- the ease with which an energy source can be used for work. Entropy- all systems move toward randomness rather than toward order. This randomness is always increasing in a system, unless new energy from the outside of the system is added to create order.

Second law of thermodynamics When energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes. Figure 2.15

2-5 What Are Systems and How Do They Respond to Change? Concept 2-5 Systems have inputs, flows, and outputs of matter and energy, and feedback can affect their behavior. System Set of components that interact in a regular way Human body, earth, the economy Inputs from the environment Flows, throughputs of matter and energy Outputs to the environment

Inputs, Throughput, and Outputs of an Economic System Fig. 2-17, p. 48

Systems Respond to Change through Feedback Loops Positive feedback loop Causes system to change further in the same direction May increase rate at which change is occurring Can cause major environmental problems Negative, or corrective, feedback loop Causes system to change in opposite direction Returns system to original state, or at least decreases rate at which the change is occurring.

Positive Feedback Loop Fig. 2-18, p. 49

More on feedback loops at the beginning of this video

What Type of Feedback Loop? Fig. 2-19, p. 50 Negative Feedback Loop

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 Tipping point, threshold level Causes a shift in the behavior of a system Melting of polar ice Population growth Nova Scotia forests

Open system- exchanges of matter or energy occur across system boundaries. Closed system- matter and energy exchanges across system boundaries do not occur. System analysis shows how matter and energy flow in the environment

Steady States In a system, when input equals output it is said to be in a steady state.

System Effects Can Be Amplified through Synergy Synergistic interaction, synergy Two or more processes combine in such a way that combined effect is greater than the two separate effects Helpful Studying with a partner Harmful E.g., Smoking and inhaling asbestos particles

Three Big Ideas 1.There is no away. 2.You cannot get something for nothing. 3.You cannot break even.

Positive, or Negative Feedback Loop? Increased CO2 in atm

Positive, or Negative Feedback Loop? The control of body temperature through sweating.

Positive, or Negative Feedback Loop? When a snowball rolls down a snowy hill, it picks up snow, which causes it to roll faster. The result is that the snowball will pick up more snow and roll even faster.

When energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes. Which law?

Percentage Measuring soil erosion in a test plot, your data shows that the soil in a test plot decreased from 30 cubic cm to 20 cubic cm. What percent change does this represent? Help with figuring percentage change (no need to sign up on the site)

Percentage Practice The estimated fish population in one section of Big Creek jumped from 1200 to 1750 in the last 3 years. What is the percentage change?

Molarity Problem A test tube contains 10 ml of a 0.5M solution. You add 5 ml of water to this. What is the molarity now?

Molarity Practice Problem You measured out in a graduated cylinder15 ml of a 2M solution. You were called away for a meeting and returned to find that only 11 ml remained. What is the molarity of the solution that remained?

Positive, or Negative Feedback Loop? iii

Positive, or Negative Feedback Loop? Fewer More Driving iii