Reasoning 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.

Theories and Laws in Science?  Both are the results of the process or method of science and the information stated in a Theory or Law have an abundant of facts to support it.

What is Energy  Energy is the work needed to move matter and the heat that flows from hot to cooler samples of matter

Energy Quality is a measure of an energy source’s ability to do useful work  High Quality energy is concentrated and can perform much useful work  Highest: Electricity, Nuclear Fission; Concentrated sunlight; high- velocity/sustained winds  High Quality energy is concentrated and can perform much useful work  Highest: Electricity, Nuclear Fission; Concentrated sunlight; high- velocity/sustained winds  Low quality Energy is dispersed and has little ability to do useful work  Lowest: Dispersed geothermal energy; normal sunlight; moderate winds; wood;

Energy quality Note that fossil fuels; coal, natural gas; gasoline (from oil) have a high energy quality (usefulness)

2nd Law of Conservation of Energy (also called the 2nd Law of Thermodynamics)  Whenever energy changes from one form to another, we always end up with less usable energy than we started with.  Eg..Our sun gives off solar energy most of it hits the earth as heat; plants use only a small part & convert it to Chemical energy; Most of this is lost at this trophic level. The next tropic level only gets 10% recall…and so it goes up through the tropic levels  Whenever energy changes from one form to another, we always end up with less usable energy than we started with.  Eg..Our sun gives off solar energy most of it hits the earth as heat; plants use only a small part & convert it to Chemical energy; Most of this is lost at this trophic level. The next tropic level only gets 10% recall…and so it goes up through the tropic levels

More examples of this 2nd law of thermodynamics  Cars use high quality energy (gasoline) but when converted to the mechanical energy that moves the car about 94% is lost to heat…so only 6% is used to move the car  Electricity (the flow of electrons) is one of the very highest forms of energy…but to give light in a light-bulb 95% of it is lost to heat..only 5% is converted to light energy  Cars use high quality energy (gasoline) but when converted to the mechanical energy that moves the car about 94% is lost to heat…so only 6% is used to move the car  Electricity (the flow of electrons) is one of the very highest forms of energy…but to give light in a light-bulb 95% of it is lost to heat..only 5% is converted to light energy

The 1st Law of Thermodynamics (law of conservation of energy)  In all physical and chemical changes, energy is neither created nor destroyed, although it may be converted from one form to another.  When we convert energy to another form energy input always equals energy output.  In all physical and chemical changes, energy is neither created nor destroyed, although it may be converted from one form to another.  When we convert energy to another form energy input always equals energy output.

What is a system?  A group of something that functions and interacts in some regular and understandable manner  Examples: our human body; a river; an ecosystem; a country; an economy; our world  A group of something that functions and interacts in some regular and understandable manner  Examples: our human body; a river; an ecosystem; a country; an economy; our world

What is a feedback loop?  Feedback loops are how systems respond to change  Something fed back into the system..energy; matter; information…can cause the system to do more of what it was doing (positive feedback) or less (negative feedback)  Feedback loops are how systems respond to change  Something fed back into the system..energy; matter; information…can cause the system to do more of what it was doing (positive feedback) or less (negative feedback)

More on Feedback Loops  Often that which is feed into the system does not have an immediate effect…this is what is meant by “time delay”. Cutting down of the forest does not immediately cause erosion for example.  However, that effect will occur. Erosion will happen. Now if we till (plow) the ground to farm this may create a synergistic interaction…The combined inputs will cause faster and more erosion than just tree cutting alone.  Often that which is feed into the system does not have an immediate effect…this is what is meant by “time delay”. Cutting down of the forest does not immediately cause erosion for example.  However, that effect will occur. Erosion will happen. Now if we till (plow) the ground to farm this may create a synergistic interaction…The combined inputs will cause faster and more erosion than just tree cutting alone.