What Is Science?

• Science is a pursuit of knowledge about how the world works

• Scientific data is collected by making observations and taking measurements

• Observations involve the five senses, and help answer questions or problems

Observation• QualitativeQualitative

– of, relating to, or involving quality or kind

– ie.: red, hot, burns quickly, etc.

• QuantitativeQuantitative– of, relating to, or

involving the measurement of quantity or amount

– ie.: 350 degrees Celsius, 5 inches, etc.

Inference1. To conclude from evidence

or premises

2. To reason from circumstance; surmise: We can infer that his motive in publishing the diary was less than honorable

3. To lead to as a consequence or conclusion: “Socrates argued that a statue inferred the existence of a sculptor”

Vocabulary

• Experiment – A procedure to study a phenomenon

under known conditions – Must have a Control

• Hypotheses – A possible explanation of something

observed in nature.

• Model – An approximate representation of a

system being studied.

Theory and Law

• Scientific Theory – A hypothesis that has been supported by

multiple scientists’ experiments in multiple locations

• A Scientific Law – a description of what we find happening in

nature over and over again in a certain way

Experiments

• Variables are what affect processes in the experiment.

• Controlled experiments have only one variable

• Experimental group gets the variable

• Control group does not have the variable– Placebo is a harmless pill

that resembles the pill being tested.

– In double blind experiments, neither the patient nor the doctors know who is the control or experiment group.

TYPES AND STRUCTURE OF MATTER

• Elements and Compounds– Matter exists in chemical

forms as elements and compounds.

• Elements (represented on the periodic table) are the distinctive building blocks of matter.

• Compounds: two or more different elements held together in fixed proportions by chemical bonds.

Ions

• An ion is an atom or group of atoms with one or more net positive or negative electrical charges.

• The number of positive or negative charges on an ion is shown as a superscript after the symbol for an atom or group of atoms

– Hydrogen ions (H+), Hydroxide ions (OH-)

– Sodium ions (Na+), Chloride ions (Cl-)

• The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution.

Figure 2-5Figure 2-5

Organic Compounds: Carbon Rules

• Organic compounds contain carbon atoms combined with one another and with various other atoms such as H+, N+, or Cl-.

• Contain at least two carbon atoms combined with each other and with atoms.

– Methane (CH4) is the only exception.

– All other compounds are inorganic.

Organic Compounds: Carbon Rules

• Hydrocarbons: compounds of carbon and hydrogen atoms (e.g. methane (CH4)).

• Chlorinated hydrocarbons: compounds of carbon, hydrogen, and chlorine atoms (e.g. DDT (C14H9Cl5)).

• Simple carbohydrates: certain types of compounds of carbon, hydrogen, and oxygen (e.g. glucose (C6H12O6)).

Cells: The Fundamental Units of Life

• Cells are the basic structural and functional units of all forms of life.– Prokaryotic cells

(bacteria) lack a distinct nucleus.

– Eukaryotic cells (plants and animals) have a distinct nucleus.

Figure 2-6Figure 2-6

States of Matter

• The atoms, ions, and molecules that make up matter are found in three physical states:– solid, liquid,

gaseous.• A fourth state, plasma,

is a high energy mixture of positively charged ions and negatively charged electrons.– The sun and stars

consist mostly of plasma.