Lecture 12 – Part 2 of Review Power

Chemistry is an experimental science and is divided into two branches, pure chemistry and applied chemistry.  Pure chemistry is theoretical and predicts results of experiments or observations.  Applied chemistry involves the practical applications of materials and reactions.  How does soap made from ashes and fat get clothes clean?  How do computer chips made of silicone (sand) carry information and electricity?

A hypothesis is a statement or idea that describes or attempts to explain observable information.

An experiment is a controlled testing of the properties of a substance or system through carefully recorded measurements.

Let’s review some key points in the history of science.  Capernicus believed that from the sun outwards, rotated Mercury, Venus, Earth (with the moon rotating around it), Mars, Jupiter, and Saturn.  This strange hypothesis was not received well since everyone knew that the sun revolved around the earth.  In 1609, Galileo used his homemade telescope to test Capernicus’ hypothesis.  Galileo took measurements and recorded data that confirmed Capernicus’ hypothesis.  In doing so he discovered the key to valid research was experimentation.  His scientific curiosity caused him to record observations regarding changing factors, such as time, position of moon, stars, and sun.  These observations and calculations led to the discovery of the four satellites of Jupiter in 1610.  Galileo’s scientific diligence is why we consider him the founder of the scientific method.

Antoine Lavoisier (1743-1794) insisted on accurate measurements and developed a theory of combustion.  He determined that combustion results from a chemical bonding between a burning substance and a component of the air, which he named oxygen.  The bonding of these two forms something new.  Joseph Priestly and Antoine Lavoisier performed experiments together and discovered that the air was composed of several different components, including nitrogen.  Previously it was thought that air was composed of one all-purpose gas.  Lavoisier found that water contained hydrogen and oxygen.  He was the first to arrange chemicals into a family of groups, and the first to attempt to explain why some chemicals form new compounds when mixed.  This is why he is considered the father of modern chemistry.

A theory is the result of thorough testing and confirmation of a hypothesis.  It predicts the outcome of new testing based on previous experimental data.

A law is a hypothesis or theory that is tested time after time with the same resulting data and thought to be without exception.

John Dalton made significant contributions to chemistry by:

Developing the Law of Partial Pressures in 1803;

developing the atomic theory (his most important discovery);

developing the law of multiple proportions;

publishing a list of atomic weights and symbols.  (This gave chemistry its initial formal vocabulary, which we memorize today.)


In case you are wondering why I am giving such a detailed background in chemistry, I will relieve your mind.  Chemistry is a part of our daily lives, as we cook, clean, breathe, and go about our activities.  NASA, the National Aeronautical and Space Administration is famous for applying basic science in new ways.  NASA uses the scientific method teams with scientists in industry to improve pharmaceuticals, optics, and bioengineering devices.  Dual purpose science and technology brainstorms are called spinoffs.


1)      Medical Gas Analyzer – Astronaut physiological monitoring technology; Used to measure operating room anesthetic concentrations, such as oxygen, carbon dioxide, and nitrogen; Ensures precise breathing environments for surgery patients.

2)      Bioreactor-  A cell culture device developed at NASA – Johnson Space Center that brings a new scientific tool to cancer and virus testing without risking harm to patients.  The rotating bioreactor walls allow three-dimensional growth of tissues without limiting pressure points.  It has successfully cultured over 35 cell types.

3)      Low Vision Enhancement System – Provides a video scene via a system of optical mirrors that project video images onto the wearer’s retinas.  The goggle-like headset help counteract the effects of macular degeneration associated with aging, diabetic retinopathy, glaucoma, and tunnel vision.

A wide variety of elements are found in the body.  These elements combine to keep our bodies healthy.

Oxygen                                                 64.6%

Carbon                                                 18%

Hydrogen                                             10%

Nitrogen                                               3.1%

Calcium                                                1.9%

Phosphorus                                          1.1%

Chlorine                                               0.4%

Potassium                                            0.36%

Sulfur                                                    0.25%

Sodium                                                 0.11%

Magnesium                                          0.03%

Iron                                                        0.005%

Copper                                                   0.0004%

Tin                                                          0.0001%

Manganese                                           0.0001%

Iodine                                                  0.0001%

Others Trace Elements Combined        0.14%

Elements Found on Earth

Oxygen (O)                                                   49.2%

Silicon (Si)                                                      25.7%

Aluminum (Al)                                                7.5%

Iron (Fe)                                                           0.005%

Calcium (Ca)                                                    1.9%

Manganese (Mn)                                            0.0001%

Tin (Sn)                                                             0.0001%

Phosphorus (P)                                                1.1%

Chlorine (Cl)                                                     0.4%

Potassium (K)                                                   0.36%

Sulfur (S)                                                           0.25%

Magnesium (Mg)                                             0.03%

Sodium (Na)                                                     0.11%

Iodine                                                                 0.0001%

Zinc (Zn)                                                            0.002%

Copper (Cu)                                                       0.0004%

Others Cumulatively                                        0.47%

So, what do these elements do for us?

Element                                                              Function in the Body

Calcium                                                               Bones, teeth, and body fluids

Phosphorus                                                        Bones and teeth

Magnesium                                                         Bones and body fluids; energy

Sodium                                                                Cellular fluids; transmission of nerve impulses

Chloride                                                               Dissolves salt in extracellular and stomach fluids

Potassium                                                            Cellular fluids and transmission of nerve impulses

Sulfur                                                                    Amino acids and proteins

Iron                                                                       Hemoglobin, muscles, and stored in organs

I hope you are finding the background information helpful.  We all have gaps and inconsistencies in our knowledge.  One of my goals has always been to fill in the educational gaps.  More than ever I am seeing liberal arts majors applying to medical school.  So many have extensive knowledge in other fields.  Intense review of the sciences is extremely important for the student doctor who majored in chemistry as an undergraduate, as well as the English major who decided that medicine is the new art form.  Now we are better equipped to continue our intense survey of human bones.  Make it a great day!


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