Science, Systems, matter, and energy

Matter: Forms, Structure, and QualityMatter is anything that has mass and takes

up space. It is found in two chemical forms:Elements—Distinctive building blocks of matterCompounds—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 CompoundsOrganic 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 MatterThree physical states

Solid

Liquid

Gas

Fourth state called Plasma—A high energy mixture of charged ions.

Matter QualityHigh-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 EfficiencyThe 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 RadiationThe electromagnetic spectrum is the range of

electromagnetic wavelengths from long (radio waves) to short (cosmic rays)

How Heat is TransferredConvection: 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 ChangesPhysical Change—no change in chemical

composition-cutting paper.

Chemical Change—change in chemical composition—frying an egg

Law of Conservation of MatterMatter 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 ThinkingScience 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 thingsEstablish that a particular model, theory, or

law has a very high probability of being true

Models and Behavior of SystemsMost systems have the following key

components:Inputs—go into the system (energy,

information)Flows or Throughputs—goes through the

systemStores—accumulates for a length of timeOutputs—moves out of the system (matter,

energy, information)

Feedback LoopsOccurs 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.