Why do I have to take a stupid science class?

Chapter 1

Science comes from the Latin word scire, which means, “to know.”

  We study science in order to understand

the world around us.  Chemistry is often called the central

science as so many naturally occurring phenomena involve chemical change.

Why do we study science? What is science?

Pure Science vs. Applied

Pure Science is the search for a better understanding of our world.

Applied science studies the application of scientific discoveries.

A pure scientist searches for newinformation.

An applied scientist wants to know how he/she can use that information.

Chemist Chemical Engineer

Science can be classified (categorized) in many ways, two of which are:

3 Branches of Science

Life science Earth science Physical Science

deals with living things,

their parts, and actions.

study of the Earth.

study of matterand energy

1. Analytical chemistry 2. Organic chemistry 3. Inorganic chemistry 4. Physical chemistry 5. Biochemistry 6. Nuclear chemistry

Chemistry, itself, can be further categorized

In a recent survey by American Chemical Society, entering college students were asked to express their attitudes about science courses.

  Chemistry was rated as the most relevant

science course.

64% rated chemistry as highly relevant to their daily lives.

Unfortunately, 83% thought chemistry was a difficult subject.

Evolution of Chemistry

The earliest concept of science began with the ancient Chinese, Egyptian, and Greek civilizations.

  The Chinese believed the universe was created by

the interaction between two forces, Yin and Yang, and were responsible for everything in nature.

600 B.C. The Greeks ◦ Science was pure reasoning.◦ The universe consisted of a single element. ◦ Thales, founder of Greek science, thought that water

was the single element. Earth is a flat disc floating on a universe of water. Air and Space were less dense forms of water and the

Earth more dense.

350 B.C. Aristotle, Greek◦ Air, earth, water, and fire were basic elements.◦ Aristotle’s influence was so great that this theory

dominated our understanding for nearly 2000 years. Fire

Water

EarthAir

Hot Dry

ColdMoist Tree: fire, water, earth

Dried Wood: fire, earth

Ashes: earth

Destruction of the Greek civilization, European science fell and did not reappear until the Middle Ages.

Eighth century A.D., Arabs◦ Introduce the pseudoscience of alchemy.◦ Alchemists looked for the magical elixir that had

miraculous healing powers and could transmute base metals into gold.

◦ Led to planned, systematic, scientific procedures and laboratory apparatus.

◦ Mainly worked by trial and error.

 Take all the mineral salts there are, also all salts of animal and vegetable origin. Add all the metals and minerals, omitting none. Take two parts of the salts and grate in one part of the metals and minerals. Melt this in a crucible, forming a mass that reflects the essence of the world in all its colors. Pulverize this and pour vinegar over it. Pour off the red liquid into English wine bottles, filling them half-full. Seal them with the bladder of an ox (not that of a pig). Punch a hole in the top with a coarse needle. Put the bottles in hot sand for three months. Vapor will escape through the hole in the top, leaving a red powder…

Recipe for the Philosopher’s Stone:

During the 1200’s, Robert Bacon, English◦ Gain an understanding of the natural world through

observations and experimentation rather than pure logic.

1661 Robert Boyle, English◦ Published The Sceptical Chymist◦ Stated that scientific speculation was worthless unless it

was supported by experimental evidence.◦ Led to the scientific method.

Late 1700’s Antoine Lavoisier, French◦ Organized chemistry into a comprehensible science.◦ Transformed chemistry from a science of observation to

the science of measurement that it is today.◦ Organized a magnificent laboratory where scientists like

Benjamin Franklin and Thomas Jefferson visited.◦ Considered to be the founder of modern chemistry.

systematic approach to problem solving. differs depending on what you are studying but there are a

few basic steps.

1. State the problem.2. Gather information on the problem.3. Form a hypothesis.4. Perform experiments to test the

hypothesis.5. Record and analyze data.6. State a conclusion.7. Repeat the work.

The Scientific Method

STATE THE PROBLEM:◦ What are you trying to find out?

GATHER INFORMATION ON THE PROBLEM:◦ Collect observations.

FORM A HYPOTHESIS:◦ Proposed solution, a tentative explanation ◦ Educated guess,

PERFORM EXPERIMENTS TO TEST THE HYPOTHESIS:◦ Carefully devised plans and procedures.

In experiments there are factors that remain the same and there are factors that change…

The constant and the variable…….

Constant(s) remain unchanged throughout the experiment.

The variable is the factor being tested. It changes or varies during an experiment.

There are two types of variables:◦ the dependent and the independent.

The independent variable is the variable that the experimenter physically changes. ◦ (Only change one at a time!!!!)

The dependent variable changes because the independent variable changed. It DEPENDS on the independent variable.

The control is the dependent variable, not influenced by the independent variable. Conducting the experiment without the independent variable, gives you a starting point for an experiment, and shows the need for the independent variable.

RECORDING AND ANALYZING DATA:◦ Record observations and measurements (aka

DATA)◦ Usually written in a table.◦ A Visual representation of the data is called a

GRAPH. The x-axis (horizontal axis, left-to-right axis) represents

the independent variable. The y-axis (vertical axis, up-and-down axis) represents

the dependent variable.

Vertical axis

Horizontal Axis

STATE A CONCLUSION:◦ Is there a pattern? Can you make a theory?

A theory gives a universally accepted explanation of the problem. Of course theories should be constantly challenged and may be refined as and when new data comes to light.

Theories are different to laws. A law is a summary of observed (measurable) behavior, whereas a theory is an explanation of behavior. A law tells what happens; a theory (model) is our attempt to explain why it happens. Laws state what general behavior is observed to occur naturally.

For example, the law of conservation of mass exists since it has been consistently observed that during all chemical changes the overall mass of the substances involved remains unchanged.

REPEAT THE WORK:◦ Check to see if the data is correct.