Science, Systems, matter, and energy

Matter: Forms, Structure, and Quality Matter is anything that has mass and takes up space. It is found in two chemical forms: Elements—Distinctive building blocks of matter Compounds—Two or more different elements held together by chemical bonds Various elements, compounds, or both can be found together in Mixtures.

Atoms—the smallest unit of an element Ions—electrically charged atoms or combinations of atoms Molecules—combinations of two or more atoms held together by chemical bonds.

Organic and Inorganic Compounds Organic compounds contain carbon combined with one or more other element. Organic Pollutants: Hydrocarbons—fossil fuels DDT-insecticide CFCs-aerosol propellant that destroys ozone Inorganic compounds do not contain carbon.

Four States of Matter Three physical states Solid Liquid Gas Fourth state called Plasma—A high energy mixture of charged ions.

Matter Quality High-Quality Matter—concentrated, found near the earth’s surface, great potential as a resource. Low-Quality Matter—dilute, found underground, beneath the ocean, or in the atmosphere, little potential as a resource.

Material Efficiency The total amount of material needed to produce each unit of goods or services. Only about 2-6 percent of the matter resources flowing through the economies of developed countries ends up providing useful goods and services because of waste.

Energy: Forms and Quality Kinetic Energy—energy in motion—wind, flowing streams, electricity. Potential Energy—Stored Energy—water behind a dam, unlit stick of dynamite, gasoline.

Electromagnetic Radiation The electromagnetic spectrum is the range of electromagnetic wavelengths from long (radio waves) to short (cosmic rays)

How Heat is Transferred Convection: The transfer of heat by the movement of heated material—through the atmosphere. Conduction: The transfer of heat by collisions of atoms or molecules—through metal. Radiation: The transfer of heat by wave motion— through space.

Physical and Chemical Changes Physical Change—no change in chemical composition-cutting paper. Chemical Change—change in chemical composition— frying an egg

Law of Conservation of Matter Matter cannot ever be created or destroyed, it can only change forms. Therefore, everything we think we throw away is still here in some form.

How Harmful are Pollutants? Three factors: Chemical nature Concentration—How much is there? Persistence—How long will it stay in the air, water, etc?

3-1 Science and Critical Thinking Science is an attempt to discover order in nature and use that knowledge to make predictions about what is likely to happen in nature. Scientific or Natural Law is a discription of what we find happening over and over in the same way.

Inductive Reasoning involves using specific observations and measurements to arrive at a general conclusion or hypothesis Deductive Reasoning involves using logic to arrive at a specific conclusion based on a generalization.

Scientists do two major things: Disprove things Establish that a particular model, theory, or law has a very high probability of being true

Models and Behavior of Systems Most systems have the following key components: Inputs—go into the system (energy, information) Flows or Throughputs—goes through the system Stores—accumulates for a length of time Outputs—moves out of the system (matter, energy, information)

Feedback Loops Occurs when an output of matter, energy, or information is fed back into a system and changes it. Positive Feedback Loop—Changes further in the same direction. Negative Feedback Loop—Changes in the opposite direction. Most systems have a combination of positive and negative feedback loops.