Christine Darden
Aerospace Engineer
Exploratorium Exhibit: Streamlines / Weather Section

As this exhibit demonstrates, the shape of a plane's wing carves the air into waves and currents that affect the plane's speed and stability. Wing and overall aircraft shape also affect sound. The sharp clap of a "sonic boom" is caused when a plane goes faster than the speed of sound (about 735 miles per hour). Breaking the sound barrier throws off a shock wave that can hit the ground at enormous pressure, sometimes intense enough to break windows and shake buildings. Darden designs supersonic and hypersonic aircraft to minimize the startling sonic boom. By changing the shape of an aircraft's wing and nose, the wave of air can be either redirected into the atmosphere or diffused, creating a softer "boom."

Garrett Morgan, 1875-1963
Inventor and Businessman
Exploratorium Exhibit: Traffic Light / Light Section

Our modern traffic light is a descendant of one patented by Garrett Morgan in 1923, at the dawn of the automotive age. Morgan observed that many accidents happened simply because people were unaware of how long it took these new-fangled inventions to come to a stop. Morgan's solution was a device with arms that extended alternately from a central pillar. Each arm was labelled either STOP, CAUTION, or GOrepresented in the modern traffic light by red, yellow, and green lights. Morgan's design also included an alarm bell. Among Morgan's other inventions was the "Morgan Safety Hood," a breathing device originally designed for fire fighters to use in smokefilled burning buildings. This early gas mask was spectacularly demonstrated at the Safety Exposition of 1914 in New York, when fire fighters raided the booth exhibiting the safety devices after a nearby trolley crash filled the subway tunnels with poisonous gases. Later modified to carry its own air supply, the modern gas mask has thousands of uses in industry and safety.

James West
Experimental Physicist
Exploratorium Exhibit: Singing Coach / Sound & Music Section

Conversion of sounds into electrical signals-in hearing aids, memory telephones, and smart information terminals-is increasingly dependent on foil electrets, co-invented by Dr. James West. Foil electrets are paperthin membranes, tiny enough to build into the most compact equipment, yet precise enough to monitor delicate changes in the rhythm of blood in human veins. Dr. West spends hours testing applications for foil electrets in the anechoic chamber of his Murray Hill lab, which the Guinness Book of World Records cites as the "world's quietest room." The checkerboard soundproofing used in many of the Sound & Music exhibits (Singing Coach; Name Those Tunes) is based on the same principle used in Dr. West's lab.

Ernest Just, 1883-1941
Biologist
Exploratorium Exhibits: Chick Embryo, Chick Heart Cells / Life Sciences Section

The basic unit of life, the cell, functions by the interactions of its three main parts: the nucleus, the cytoplasm that surrounds the nucleus, and the ectoplasm that forms the cell's boundary with the outside. Traditional biology held that the nucleus was dominant in the control and function of a cell-an oversimplified notion, as you can see in the Cells exhibit. Dr. Ernest Just's research on the egg cell showed that the ectoplasm, as the cell's point of communication with the outside environment, was crucial for growth and development (see the Chick Embryo exhibit). Fertilization, for example, depends strongly on the ectoplasm's integrity as a barrier, its changing chemical makeup, and the speed with which it reacts to the presence of sperm cells. Much of Dr. just's work on the egg cells of marine life forms was done at Woods Hole Marine Biology Labs in Massachusetts. His pioneering research redefined how we think about cells and helped reveal the essential differences between plant and animal cells, and living and non-living matter. Charles Drew, 1904-1950 Surgeon, Medical Researcher, and Educator Exploratorium Exhibit: Sickling Cells / Life Sciences Section Much of our knowledge of how blood functions in the body- including the basis for understanding sickle-cell anemia, a blood disease which predominately affects African-Americans-is based on the pioneering work of

Dr. Charles Drew
Surgeon, Medical Researcher, and Educator
Exploratorium Exhibit: Sickling Cells/ Life Sciences Section

Much of our knowledge of how blood functions in the body- including the basis for understanding sickle-cell anemia, a blood disease which predominately affects African Americans - is based on the pioneering work of Dr. Charles Drew.
Best known as the inventor of the blood bank, Dr. Drew spent much of his tragically short career investigating blood chemistry, fluid balance, and blood transfusion. The basic blood types (A, B, AB, and 0) were known when Dr. Drew began his work, but there were no methods to collect, type, and preserve blood so it would be available for hospital surgeons. Spurred by the onset of World War 11, Drew and his colleagues created the modern blood bank,
developing uniform standards for collection, treatment, and preservation of donated blood. Thousands of lives were saved in the early months of the war, thanks to the military blood banks that Dr. Drew helped establish. However, widespread controversy was ignited in 1941 when the Armed Forces and the American Red Cross declared that the blood from black donors would be segregrated from that of white donors in blood banks. Dr. Drew hotly protested the decision, stating that there was no scientific reason for separating blood on the basis of a donor's race. The controversy was still raging when, in 1950, Dr. Drew was critically injured in an automobile accident. Immediate medical attention and a blood transfusion might have saved his life; it is widely believed that he was refused admission at the nearest hospital because he was black.

Percy Julian, 1899-1975
Organic Chemist and Researcher
Exploratorium Exhibit: Cow's Eye Dissection / Life Sciences

Section Glaucoma, a common form of blindness, is caused when pressure w1thin the eyeball destroys the retina. One of the few treatments available for glaucoma is the drug physostigmine, which can be extracted from calabar seeds. The drug had been known since 1865, but was prohibitively expensive to produce from its natural source. Dr. Percy Lavon Julian of DePauw University was the first to synthesize physostigmine, using the plentiful and cheap soybean as a base. When his invitation to become DePauw's dean of chemistry was withdrawn because of racial prejudice, Dr. Julian accepted the position of research director at Glidden Paint Co. There he developed scores of other soybean derivatives: paper coatings, paint bases, fire-extinguishing foam (called "bean soup" by the armed forces, who used it extensively). Some of his most important work was in developing synthetic hormones, including cortisone, which is used in the treatment of rheumatoid arthritis. Founding his own companies, Julian Laboratories in Illinois and Laboratorios Julian de Mexico, he continued in basic research and was doing pioneering work in birth control chemistry at the time of his death.

Patricia Cowings
Psychologist and Space Medicine Researcher
Exploratorium Exhibit: Silage Beach / Vision Section

If using this exhibit makes you queasy, imagine floating around a spacecraft in zero gravity with no idea which way is "up." One of the most crucial and least acknowledged scientists in our space program is Dr. Cowings, an expert in preventing space sickness. To help astronauts overcome nausea in space, Dr. Cowings first has to make them sick on the ground. From that, she can determine the physiological changes that precede motion sickness. Then she designs an individually tailored program of biofeedback, training the astronaut to control the physical and metabolic reactions that trigger nausea.

Lewis Latimer, 1848-1928
Electrical Draftsman and Inventor
Exploratorium Exhibits: Carbon Filament Lamp, Series-Parallel Circuit / Electricity Section

The antique carbon-filament bulb in this exhibit owes a lot to Lewis Latimer. He not only invented the first reliable method for attaching the filament to the bulb, he also developed a mass-production method and a sturdy, reliable material for the filament itself. Once cheap, mass-produced light bulbs were available, Latimer turned his attention to the next major obstacle to supplying power to city residents: how to connect electric street lamps. The old method wired the lights together in a series circuit, which meant if one bulb blew out, the entire system went dark. Latimer was reponsible for making parallel wiring the standard, independently connecting each light to the power source. Electrical inventions and patents were a source of fierce competition between Thomas Edison and his major rival, Hiram Maxim, both of whom had employed Latimer at one time. Recognized for his encyclopedic knowledge of the fledgling electrical industry, Latimer was a crucial expert witness for Edison in a series of lawsuits against Maxim. As the only black member of the Edison Pioneers, Latimer held numerous patents in every aspect of electricity and literally "wrote the book" on the subject: Incandescent Electric Lighting: A Practical Description of the Edison System.

Granville T. Woods, 1856-1910
Inventor
Exploratoriurn Exhibit: Series-Parallel Circuit / Electricity Section

Dimmer switches, like the one used in this exhibit, were invented by Granville T. Woods, a contemporary of Louis Latimer. The dimmer switches used in theaters in the 1890s were bulky, and threw off a great deal of heat--enough to cause frequent theater fires. Woods' dimmer was far safer, used only 40% as much electricity, and led the way to the compact, inexpensive dimmers we use today. Woods was an extremely prolific and creative inventor. He patented a system that allowed operators to transmit oral messages over telegraph lines, eliminating the need to memorize Morse code. One of his most important inventions was the induction telegraph, a device which allowed communication between moving trains and railway stations. The invention prevented countless accidents, as conductors could be forewarned of obstacles ahead. Known as the "Black Edison," Woods was the holder of over 150 patents for electrical innovations, communications equipment, and public transportation safety. Woods' inventions have endured: train-to-train telegraphs and the overhead electric cable for trolleys and BART's electric third rail are all based on his patents.

Elijah McCoy, 1844-1928
Mechanical Engineer and Inventor
Exploratoriurn Exhibit: Steam Engine / Mechanics Section

The moving parts of any machine stop moving when friction causes resistance. Friction can be overcome by lubricating the machine with a thin film of oil or grease. Until the 1870s, it was standard practice to stop the machine, train, or entire factory to apply lubricating oil by hand. Elijah McCoy, frustrated in a train stoker's job despite his degree in mechanical engineering, realized it should be possible for the machine to oil itself without having to shut the engine down. McCoy's patented invention of the automatic lubricating cup (look at the thin pipes dripping oil into flat funnels on the two moving pistons) provided a continuous, monitored flow of oil to the engine's moving parts. Automatic lubrication saved time and labor, and the machines employing it were safer and more reliable to operate. The "real McCoy," an expression coined to describe this self-lubricating process, still stands today to signify genuine quality.