Today in History – February 1, 1972 – First scientific hand-held calculator, the HP-35, introduced for $395. I was an undergraduate in engineering when the HP-35 was released. I couldn’t afford to buy one and stuck with my slide rule. But the next year, I gave in and bought the next model, the HP-45 and it was well worth the money at the time. The calculators were easy to use, portable and reliable. The market responded by developing cheaper calculators, while Hewlett Packard kept the cost high and increased the functionality.

Check out the Engineering Pathway’s educational resources on the electronic calculators and history of computing. For more educational resources, see our electrical engineering education and computer engineering education community pages. The Engineering Pathway also hosts Engineering Education communities in all ABET-accredited disciplines.

Today in History – January 31, 1958 – Explorer 1 became the United States of America’s first satellite to orbit the Earth after it was launched on January 31, 1958. After the Soviet Union’s successful launch of Sputnik I on October 4, 1957, the United States of America embarked upon a program to launch it own artificial satellite. The first American attempt to launch a satellite using a Vanguard 1 rocket occurred in December 1957 and failed miserably.

Following this failure, the U.S. Army Ballistic Missile Agency, located at Redstone Arsenal in Huntsville, AL, was directed to launch a scientific satellite using a Jupiter C rocket developed under Dr. Wernher von Braun. The artificial satellite was designed, built and operated by the California Institute of Technology’s Jet Propulsion Laboratory under the direction of Dr. William Pickering.

The satellite instrumentation of Explorer 1 was a cosmic ray counter designed by Dr. James Van Allen, a physicist at the University of Iowa. The cosmic ray counter experiment was designed to measure the radiation that surrounds the Earth. Once in orbit, the cosmic ray counter began to overload and measured a much lower cosmic ray count than previously assumed. Given this new information, Dr. Van Allen theorized that the cosmic ray equipment may have been exposed to very strong radiation caused by a belt of charged particles trapped in space by Earth’s magnetic field.

The data returned by Explorer 1 and another satellite launched in March 1958 prove the existence of intense belts of radiation that surround the Earth. These belts of radiation are now called Van Allen Belts and are considered to be the first major scientific discovery of the space age.

Check out the Engineering Pathway’s educational resources on the Explorer I and satellites. For more educational resources, see our aeronautical engineering education and electrical engineering education community pages. The Engineering Pathway also hosts Engineering Education communities in all ABET-accredited disciplines.

Today in History – January 28, 1986 – Space Shuttle Challenger explodes after launch, killing the entire crew. American’s stared in shock at their televisions watching the Challenger accident in full motion video. The 35th Challenger’s flight had been previously scheduled for January 22, but delayed because of bad weather, high winds and icicles on the launch apparatus. Never had there been a launch approved in freezing weather conditions, but NASA had assured the public that the conditions were safe. They were anxious to launch due to economic considerations and scheduling backlogs. Political pressure has been suggested as well due to NASA’s heavy publicizing of Christa McAuliffe as the first school teacher in space. She had been selected under a highly competitive process from among 10,000 entries for the opportunity. The Challenger disaster was a severe blow to the American space program, bringing manned flights to a halt for many years. It was also a blow to the American public who had come to think of the Space Shuttle as an important symbol of national identify.

Speaking before the launch, Christa McAuliffe said: “One of the things I hope to bring back into the classroom is to make that connection with the students that they too are part of history, the space program belongs to them and to try to bring them up with the space age.”

Morton-Thiokol, one of the contractors for the Solid Rocket Motor was convinced that the cold weather would cause problems and had briefed NASA about their concerns. Two engineers, Robert Ebeling and Roger Boisjoly had previously urged a redesign on the booster rockets due to O-ring erosion in the booster field joints. The lowest temperature experienced by the O-rings in any previous mission was 53°F in the January 24, 1985 flight; the temperature predicted for Florida on January 28th was much lower, in the low 20′s °F.

The Rogers commission confirmed the cause of the Challenger disaster explosion to have been caused by a leak through the faulty O-ring seal in one of the solid rocket boosters. According to testimony by Morton-Thiokol engineer Boisjoly, management put pressure on the engineers to OK the launch saying: “Take off your engineering hat and put on your management hat.” The recommendation was reversed, discounting the concern about the O-rings as being “inconclusive” and launch was recommended, “based on their engineering assessment”, even though the engineers had no part in this recommendation. In spite of concerns expressed by others, NASA managers decided to approve the boosters for launch despite the fact that the predicted launch temperature was outside of their operational specifications and any test conditions.

Engineers must learn from both the technical and organizational failures that led to the tragic Challenger accident. The Engineering Pathway digital library has information on several excellent case studies, lesson plans and other curricular materials that can be used in the classroom. The Texas A&M case, for example, leads to these discussions questions:

• “What could NASA management have done differently?
• What should Roger Boisjoly have done differently (if anything)? In answering this question, keep in mind that at his age, the prospect of finding a new job if he was fired was slim. He also had a family to support.
• What do you (the students) see as your future engineering professional responsibilities in relation to both being loyal to management and protecting the public welfare?”

For more information, see the Engineering Pathway’s resources on the Challenger accident or engineering ethics.

Today in History – January 26, 1697-  Isaac Newton solves Bernoulli’s brachistochrone problem, inventing the “calculus of variations”. The story goes that Jean Bernoulli gave Isaac Newton a challenge solve the following problem in six months:

We are given two fixed points in a vertical plane. A particle starts from rest at one of the points and travels to the other under its own weight. Find the path that the particle must follow in order to reach its destination in the briefest time.

Rather than take 6 months, Newton is reported to have solved the problem the next day. However, the solution, which is a segment of a cycloid, was solved, in part, by Leibniz, L’Hospital, Newton and the two Bernoullis. In fact, there appears to have been quite a lively, and in some cases bitter, debate about the fine points of the solution. Regardless, the challenge was to provide the seed for further development of the theory of calculus of variation used in a wide range of engineering problems, such as optimal control and optimization.

For more information, see the Engineering Pathway’s resources on Isaac Newton, the Brachistochrone problem and calculus of variations.

Also on this date in 1905, Cullinan Diamond (“Star of Africa”), the largest diamond ever found, is unearthed. On January 26, 1926, Scottish Engineer John Baird gives first public demonstration of television in London. And in 1992, Americans with Disabilities Act went into effect. Check out the Engineering Pathway’s resources on teaching and learning for persons with disabilities.

Today in History – January 24, 1984 – Apple Computer unveils the Macintosh personal computer. Apple introduced “the Mac” through its famous “1984″ television commercial that was played at the 1984 Super Bowl. The imagery pitted Apple’s new generation of the people’s personal computer against the Orwellian IBM. The Mac was an innovation breakthrough in computer design with the introduction of the mouse and a graphical user interface at a relatively low price.  It was first sold with only a 400kb floppy drive to load the operating system and files, with no hard drive. Less than 50,000 units were sold after its introduction because of the limited memory and radical features. Sales got a big boost when the LaserWriter printer was introduced along with third party publishing software. The early Mac users provided an enthusiastic customer base of early adopters who formed community groups, participated in early testing and developed third part software using Apple’s user-friendly developer’s kit. My husband and I each bought one of the first offerings and have upgraded to new Apple models ever since. The summer of 1984 I accepted a faculty position at the University of California at Berkeley and my husband became an Apple developer and created software for astronomy enthusiasts.

A decade earlier on April 1, 1976, the Apple Computer Company was formed and released the Apple I computer, the first computer with a single circuit board. There was no assembly line as each Apple I was hand-built by Steve Wozniak in Steve Jobs’ parents’ home and required further assembly by the purchaser, including providing AC input voltages, wiring an ASCII keyboard to a DIP connector and wiring the video output pins to a monitor or to an RF modulator if a TV was used. Steve Wozniak showed the first one to the Homebrew Computer Club to get sales going. He had to sell his Volkswagen bus to help keep the company afloat.

Steve Wozniak designed the Apple II personal computer that was released on April 16, 1977, featuring a central processing unit (CPU), keyboard, floppy disk drive, and a $1,300 price tag. The Apple II launched the personal computer revolution. He left Apple in 1981 and went back to the University of California at Berkeley and finished his degree in electrical engineering and computer science there. Since then, he has been involved in various business and philanthropic ventures, including improving computer capabilities in schools.

So how do you build the first personal computer? Wozniak says when he teaches Personal Computer 101 he asks students to go to the Apple I Owners Club, founded in 1977 by Joe Torzewski. The site contains over 120 pages detailing the Apple I computer. It shows you what it was like to actually buy and assemble one. If you’ve never seen an Apple I, check this site out and see how the personal computer revolution began. Want to know more, read Wozniak’s book: iWoz: Computer Geek to Cult Icon: How I Invented the Personal Computer, Co-founded Apple, and Had Fun Doing It.

Check out the Engineering Pathway’s educational resources on Apple computers and history of computing. For more educational resources, see our electrical engineering education, computer science education and computer engineering education community pages. The Engineering Pathway also hosts Engineering Education communities in all ABET-accredited disciplines.

Today in History – January 17, 1871 - U.S. patent issued for an “endless wire rope way” cable car (No.110,971). The inventor of the cable car was Andrew S. Hallidie (center image above) and contracted by the Clay Street Hill Railroad Company in San Francisco. Hallidie’s system used a continuous looped wire rope that was placed in a tube below the surface of the ground. A motor kept the rope in continuous motion (first image below) and the rope was grasped and released by a griping device on the passenger car and controlled by the “driver”. Bells were used to warn other cars and pedestrians that a cable car was on its way. A code was developed so that the bell could be used to communicate between cable car drivers as well.

Legend has it that Hallidie’s inspiration for the cable car came in 1869 after witnessing horses being whipped while they struggled on the wet cobblestones to pull a horsecar up Jackson Street. When a horse slipped, it was sometimes dragged to its death.

Hallidie’s design was described in the Scientific American Supplement, September 17, 1881 with the title: The Wire Rope Street Railways of San Francisco, California. Hallidie describes how his cable car system operates and the various San Francisco companies (at that time) that had successfully adapted the cable car for their street railway company.

Andrew Smith Hallidie tested the first cable car at 4 o’clock in the morning, August 2nd, 1873, on Clay Street, in San Francisco. For more information, see the San Francisco Cable Car Museum and find out more about how cable cars work, their history and where they operate today. Or check out the Engineering Pathway’s educational resources on cable cars and mass transportation systems.

Cable cars are a great example of the application of simple machines and mechanical advantage. For more information see the Engineering Pathway’s curricular resources and the Mechanical Engineering Education disciplinary community.

Today in History- January 15, 1955 – first solar-heated and radiation-cooled house in the United States. Respect for the powers of the sun has been a critical part of building design since humans first built shelters for protection from the environment. I grew up in the American Southwest and recall that adobe buildings were designed to cool in the summer and retain heat in the winter through appropriate use of thermal mass, windows and passive air circulation systems. Solar water heating was used in Florida, California, and the Southwest as early as the 1920s but never took off as a viable commercial industry.

Raymond W. Bliss (6 Oct 1915 – 7 Nov 2004) is credited with building the first integrated solar heating and radiation cooling house in Tucson, Arizona in 1955. Built at a cost of approxiamately $4,000 for labor and materials, the house used a large slanted slab of steel and glass that captured heat from the sun, which was ducted into the house. Summer cooling used the same ducts and associated fans and controls.

For more information, see the Engineering Pathway‘s resources on solar energy, green and sustainable building design and architectural engineering. Curricular resources can be found on the Architectural Engineering Education Community site.

Today in History – January 14, 2005 – Huygens Probe Lands on Titan.

After spending seven years in space, the Huygens probe separated from the main Cassini spacecraft on December 24, 2004, and spent the next three weeks traveling to the moon Titan. After beginning its descent, it transmitted scientific data for nearly five hours before running out of power. The Huygens probe was named after the Dutch astronomer Christiaan Huygens. He is credited with the discovery of Titan and thus it was deemed fitting to name the probe after him.

For more information, see the Engineering Pathway’s related resources Saturn and Cassini. Or visit the Aerospace Engineering Education community site.

Today in History – January 13, 1942 – Henry Ford patents a plastic automobile.

The plastic car Ford patented used soy-based plastics and was 25% to 33% lighter than conventional cars of his day. Ford’s dream was to use agricultural-based plastics to provide another market for farmers to sell their crops.

Sustainability in design is beginning to make a comeback as manufacturers are using recycled products in car interiors. However in today’s oil-conscious world, car manufacturers are focusing most heavily on hybrid vehicles and fuel diversity. A variety of new cars are equipped with engines that are designed to run on both traditional gasoline and an ethanol blend. And although many more plastics and composites are being used in cars, they are not of the type that Ford envisioned. A recent article in Business Week (“Lighter Cars Can Help the U.S. Kick Oil”) points out that vehicle weight has only risen over recent decades. A significant decrease in weight, like the one that Ford initially achieved, could be just as beneficial to fuel economy.

For more information, see the Engineering Pathway’s related resources plastics and their applications. Or visit the Materials Engineering Education or the Mechanical Engineering Education community sites.

Today in History – January 6, 1851 – Foucault physically demonstrates the rotation of the Earth. Now this isn’t so easy to do because the earth rotates pretty slowly. How slowly? Well, it takes a full day to go around once, eh? So in a minute it’s going to rotate about, oh, 0.0007 revolutions. Not much. Certainly nothing you’re going to feel. So how to show it? Well, you could always point to the fact that the stars and sun go around us once a day, and figure that should be enough of a demonstration for a reasonable person. But people are often unreasonable!

So to make it all very real and exciting, Jean Bernard Léon Foucault decided it wasn’t enough just to have a cool name (you have to admit – that is a pretty cool one) and dreamed up what’s become known as the Foucault pendulum.  In 1851, Jean he obtained a nice chunk of metal (to the tune of 28 kilograms), and suspended it from the ceiling of the dome of the Pantheon in Paris. And when I say suspended, I mean SUSPENDED. 67 meters of suspension (or about 220 feet for those of you who still aren’t 100% metricized). That’s a BIG pendulum.

Since then there have been a whole bunch of these Foucault pendulums set up and they’re pretty nifty. Basically all you do is pull the weight to the side and let go. It then ticks back and forth (no surprise). And the earth rotates underneath. Which means that the ground slowly misaligns itself as the pendulum happily continues in its original tick-tock direction.

Usually they’ll do something like place little pegs in a big circle on the floor and there’ll be a tip extending from the bottom of the pendulum that slowly, ever so slowly, gets closer and closer to one of the pegs as it does its tick tock thing. And then it’ll juuuust brush the peg. Then nudge it. Then BOOM! Over it goes. Some minutes later the next one goes. And the next. All the way up until closing, when the guy in charge has to collect all the pegs and then, before the doors open the next day, set ‘em all up again. Hey, it’s a living.

Anyway, it’s a very satisfying way to waste a few minutes. I recommend it highly.

For more information, see the Engineering Pathway’s resources on Foucault’s Pendulum and pendulums. For related educational resources, visit the Engineering Mechanics or the Mechanical Engineering Education disciplinary communities