Chobhi's Blog

I shall never forget my dear friend who obtained her doctorate years before I did in Chemistry  and tried to apply for a job in a different state in India.  Her interviewers were very impressed with her credentials.  Yet, shockingly, they gently dissuaded her from moving away from her husband and children to follow the new job opportunity, even though her spouse was happy to let her persue her career!   She was quite upset by the sexism shown by the men who were interviewing her.

That was in the 70’s and I still see it today.   A few years ago, I was teaching a chemistry class along with a new male teacher to acquaint him with our methodology. He made me demonstrate the laboratory activity and clean up.  Then he proceeded to lecture without even a ‘Thanks ‘ for doing all the grunt work.  I refused to ever work with him after that.

There are numerous examples of talented, intelligent scientists out there who are not white men.  Unfortunately, most students in the field of science and medicine hear about the work of only white men in these fields.  ( As a science student, I heard names like Priestley, Lavoisier, Gauss, Watson, Crick, but never the names of women or non-white chemists, biologists or mathematicians,  for example.  I thought there were none.) There are ample stories of sexism, racism directed at women and non- white scientists and the side- lining of their hard work.  This week , and till week 52, we shall look at a few of these amazing, pioneering women and people of color scientists from the past to the present.

Mary Putnam Jacobi, an American, was the first woman to be admitted to France’s Ecole deMedicine (Medical School) in 1867. She had already received her MD in the United States.  During this time Edward Clarke, MD at Harvard had written a book called A Fair Chance for Girls claiming that women who spent too many years studying would have under- developed ovaries and would become sterile!   Women menstruated and hence exertions (by studying long hours) during this time would make them sterile. Mary did not believe this and came up with hard facts and numbers using test subjects before, during and after menstruation.  This paper won the Boylston Prize at Harvard and paved the way for women to gain opportunities in higher education, especially the sciences. Mary finished her Medical School in France and continued practicing and lecturing in New York. (Ref.1)

Alice Ball, an African- American, had a Master’s degree in Chemistry from Hawaii in 1915.  She managed to create a less viscous oil that could be injected and absorbed by the body  in the treatment of leprosy.  This was a major breakthrough in the treatment.(Ref.1)

Chien-Shiung Wu was born in Shangai, China, but came to the U. S. to study in Berkeley, California. Her father was an outspoken advocate for women.  She received her doctorate in physics in 1940.  During World War II, she focused her attention on beta decay.  Wu worked on her base material meticulously to prove Fermi’s Theory on beta decay.  She worked on sub-atomic particles relentlessly and isolated the K-meson into an observable state.(Ref.1)

Priyamvada Natarajan is a professor of astronomy and physics at Yale University (featured picture).  She is interested in cosmology,gravitational lensing and black hole physics. Her research involves mapping the detailed distribution of dark matter in the universe using the concept of ‘the bending of light’ coming from distant galaxies! (Ref.2)

Her undergraduate degree was in physics and mathematics, her master’s degree was in Science, Technology and Society from M.I.T., Boston.  Her doctorate work was in theoretical astrophysics.  She was the first woman to be elected fellow of Trinity College, Cambridge.  She has received several awards, including the Sofie and Tycho Brahe professorship in Copenhagen, Denmark.   Priyamvada is deeply interested in institutional change with regards to gender parity in the academic world.  She actively engages in encouraging numerical and scientific  literacy for the public at large. She has been interviewed by NPR and several prestigious newspapers and media outlets.  (Ref.2)

Priyamvada has recently published a book on the history of astronomy called “Mapping the heavens.”(Ref.3)

Ellen Ocho is an astronaut.  She received her master of science and doctorate degrees from Stanford University.  Her doctorate degree was in electrical engineering.  She is a leading research scientist with several patents and is the first Latina to go in space. (She was selected by NASA in 1990.).  She is a veteran of four flights in space.  She has received numerous awards including Outstanding Leadership Medal in 1995.  Besides being an astronaut, engineer and researcher, Ochoa is a classical flutist. ( Ref.4)

I have barely scratched the surface of amazing women scientists, from the past and the present (including names in Nuggets).  Do your own research and marvel at these wonderful women who make us proud!

Nuggets of Information :

According to the U.S. Bureau of Labor Statistics(2015), women make up 47% of the total workforce, and comprise 37% of chemists and material scientists, 28% of environmental and geoscientists and only around 16-12% of engineers.(Ref.5)

Chien-Shiung Wu was called ” The First Lady of Physics”(Ref.6)

British chemist Rosalind Franklin is best known for her pioneering work in crystal diffraction and her role in the discovery of DNA structure.  Though Watson and Crick were awarded the Nobel Prize , very few know about Rosalind’s significant contribution. Unfortunately, she died before the Prize was awarded.  She never complained that Watson and Crick based their article using her research work.(Ref.7)

Vera Rubin who died in December of 2016, had to fight to get access to a telescope.  She was an asro- physicist who worked for decades at the Carnegie Institute of Science in Washington, D.C. She was a pioneer in the discovery of dark matter.  The concept of dark matter had limited evidence in the 70’s as Rubin and her colleagues studied the dim light coming from distant galaxies. (Ref.8).  Thanks to her persistent research we now have evidence not only about dark matter but dark energy and the possibility of ‘multi- verses’.

References:

1.Swaby, Rachel, Headstrong  52 Women who changed Science and the World,  (Broadway Books, New York,2015)

2.astroyale.edu/priya/

3.Natarajan, Priyamvada, Mapping the Heavens,

4.biography.com/people/Ellen-Ochoa-10413023#nasa

5.usnews.com/news/articles/2015/10/21/women-still-underrepresented-in-stem-fields

6.  nwhm.org,go to History Makers and choose’Wu’

7.biography,com/people/rosalind-franklin-9301344#scientific-discoveries-and-credit-controversy

8.latimes.com/local/obituaries/la-me-vera-rubin-20161226-story.html

With the recent election in 2016, several ballot measures were passed that supported medical marijuana as well as recreational marijuana in some states in the U.S.  Terpenes are the main class of aromatic compounds found in cannabis or marijuana as it is popularly called.  Yet, this is only a part of the field of terpenes, terpenoids that are organic hydrocarbons produced by a wide variety of plants.(Ref.1)

The term ‘terpene’ is ascribed to compounds isolated from terpentine, the volatile liquid found in pine trees.   Terpenes were originally used to describe a mixture of isomeric hydrocarbons of the molecular formula C10H16 found in the essential oils obtained from the sap and tissues of plants and trees.  The modern definition is more broad-based:Terpenoids are the hydrocarbons of plant origin of the general formula(C5H8)n, as well as their oxygenated,hydrogenated and de-hydrogenated derivatives. (Ref.2)

Here is a simple table to illustrate the classification of terpenes:

#of carbon atoms      Value of n       Class

10                                   2                     Monoterpenoids(C10H16)

15                                    3                  Sesquiterpenoids(C15H24)

20                                   4.                 Diterpenoids(C20H32)

25                                   5                    Sesterpenoids(C25H40)

30                                   6                   Troterpenoids(C30H48)

40                                   8                   Tetraterpenoids (C40H64)

More than 40     More than 8        Polyterpenoids(C5H8)n

Each class can also be subdivided according to the number of rings present in the structure:

1.Acyclic terpenoids-open structure

2.Monocyclic /bicyclic/ tricyclic terpenoids-containing one/ two/three rings in structure. (Ref.2)

Thermal decomposition of a terpene leads to isoprene as one of the products. (Ref.2). What is an isoprene?  This is the C5H8 building block for a terpene, (where (C5H8)2; i.e., n=2 for the first terpene, as shown in the table above) the structure includes two double bonds: CH2=C(CH3)CH=CH2.

Most terpenoids are colorless fragrant liquids, lighter than water and volatile with steam.  A few are solids like camphor.  All are soluble in organic solvents and mostly insoluble in water, and optically active. Since they can be open-chain or cyclic unsaturated compounds, they can undergo addition reactions with halogens, hydrogen, acids. The addition products have antiseptic properties.  Terpenes also undergo oxidation, polymerization.   On thermal decomposition, most of the terpinoids result in isoprene as one of the products. (Ref.2)

Let us look at some common examples of terpenes:

1.Limonene is comprised of two isoprene units and can be expressed as (C5H8)2 which is then C10H16.  From the above table it is a mono terpene.  Limonene is a mono terpene responsible for the fragrance of citrus fruits.  D- Limonene is widely used as a flavor additive in the food industry as well as an aroma in the perfume industry.  It is also used medicinally to reduce heartburn and gastric reflux.  Sometimes it is used in cleaning solvents and for stripping paint. (Ref.1)  It is a Monocyclic monoterpenoid. (Ref.2)

2. Myrcene is another mono terpene and is the most abundant terpene found in cannabis.  But it is also found in bay leaves, wild thyme, hops, verbena.  It produces analgesic effects in laboratory testing on rats. (Ref.1).  Myrcene is an Acyclic mono terpene. (Ref.2)

3.Pinene: as the name suggests, is found in pines and conifers and it exists as two isomers, alpha and beta pinene, mono terpenes. Turpentine is a large part of pinene.  These pinenes are also present in sage,( both isomers).  Olive, rosemary , sassafras and bergamot contain the alpha isomer while hops and cumin have the beta isomer.  It acts as a natural herbicide and also acts as a bronchodilator in humans. In addition, pinene shows antibacterial, antibiotic properties. (Ref.1)

4. Linalool is a mono terpenoid of the chemical formula C10H18O. It is found in mint,laurel, cinnamon, birch , lavender and some citrus. There are two non- superimposable mirror image isomers for linalool.  Linalool is used as an anxiety inducing drug.  Lavender has been used for thousands of years as a calmative.  Recent tests on rats exhibit its sedative and motor relaxant effects. (Ref.1)( More information about the isomers and examples in Nuggets)

There are several more examples that have not been mentioned here, but suffice to see that terpenes and terpenoids are a wide and extensive resource for us.  Their medicinal uses go back centuries; lavender is just one example. Many herbs and spices like ginger , cloves and cinnamon have been used for centuries in countries like India for home- made health remedies and in the field of Ayurveda medicine.  Today, especially with the possibility of the usage of medical marijuana, the additional terpenes and terpenoids can be combined with cannabis in research and enhancement of therapeutic effects.

Activities for Middle School Teachers:

Students can create the basic isoprene unit and look at common terpene and terpenoid structures.  What limits the structural possibilities? What is the gem dialkyl rule? (Ref.2)

Students  can get a spice or herb used in their foods and find out if it is a terpene or terpenoid.  Let them then build the structure and do a presentation on their terpene/ terpenoid.

Students should have an open discussion about cannabis and talk about the pros and cons of using cannabis.  What kind of societies are created in countries where it is legalized ? Is it better or worse than in the U.S.?  Should there be incarceration for using /possessing small amounts of cannabis? How about focusing on the medicinal uses of cannabis?

Nuggets of information:

Beta- carophyllene, a sesquiterpene is found in cloves, rosemary and hops and exhibits anti- inflammatory effects.  Carophyllene oxide is the substance in cannabis that is identifiable by drug-sniffing dogs. (Ref.1)

Both alpha and beta pinene are present in cannabis; in fact cannabis may contain over 120 terpenes and terpenoids, albeit many of them may be present in trace amounts.  Today the medicinal uses of cannabis, besides the popular assumption that it is mainly used for recreational purposes, is being seriously studied. (Ref.1)

Citral, very similar to Limonene, but has an aldehyde and is an Acyclic mono terpenoid.  It is found in lemon grass oil. (Ref.2)

Other common terpenoids include eugenol (cloves), anethol (fennel, anise), menthol (common cold products),thymol (thyme,oregano), and geraniol (roses).   Camphor is also a terpene. (Ref.3)

Notice that most of the above terpenoids end in ‘ol’ indicating an alcohol or presence of an -OH group.

As terpenoids were found in essential oils, they were used for religious reasons in Ancient Egypt.  Camphor was introduced to Europe from the East by the Arabs in the 11th century.  The process of obtaining  some 60 plant essential oils was described in a book written in 1592. (Ref.3)

References:

1.sensiseeds.com/en/blog/medicinal-properties-terpenes-terpenoids/

2.nsdl.niscair.res.in/jspui/bitstream/123456789/700/1/revi

3.food.info.net/uk/qa/qa-fi69.htm

I look at Hillsborough Bay in Florida to see a placid water body and the seagulls screeching while the brown pelicans sit on the wooden pole perches. And I wonder…… if they could talk to me would they tell me what really happened to their families and the humans around them six years ago during that oil rig explosion?  What really lurks beneath the calm blue waters?

The Gulf of Mexico is known for its rich variety of flora and fauna and also a long coral reef.  Pulley Ridge, 150 miles west of Cape Sable, Florida,has the deepest coral reef in the U.S.  There is another coral reef 110 miles south of the Texas- Loiusiana border.  The whooping crane, the peregrine falcon,piping plover, brown pelican and even the bald eagle make their home here in the gulf.  The shrimp and  fish industry supplies most of our sea food.   There are also a variety of endangered species of whales found in these waters.(Ref.1)  The area is at the same time, also rich in fossil fuel deposits under water.  Off- shore oil rigs have become the way to keep drilling for more oil by those not willing to look for alternative/green sources for our energy needs.

Deepwater Horizon was the name of an ultra-deepwater semi-submersible off-shore oil rig owned by a company called Transocean and leased to BP from 2001.  On 20th April, 2010, while drilling at the Macondo Prospect, an explosion on the rig caused by a blowout killed 11 crew members, ignited a fireball visible from 40 miles away.  The resulting fire could not be extinguished and in the process of doing that, the rig sank, leaving the well gushing and causing the biggest oil spill in U.S. waters.(Ref.2)

Drilling for oil, especially oil that is deep under water, is considered an acrobatic feat.  The crew drills the pipe to hit the oil level and the deeper one goes, the greater is the pressure of oil and mostly methane gas.  The comparison is made with a giant bag of popcorn taken out of the microwave ready to be opened buried under 5,000 feet of ocean and 13,500 feet of earth.  Instead of ripping the bag open, you insert an 18,500- foot straw, actually a pipe and then place a thumb over the straw, so the contents do not explode.  The air in the bag contains methane, the popcorn is the crude oil while the thumb is the cement used to seal the hole. (Ref.3)  Managing the pressure at such depths to bring up the oil and gas mixture in a controlled manner is called well- control. Problems managing the pressures is called a kick , whereas, loss of well- control is called a blowout.(Ref.3)

Why did the blowout occur?  It was later learned that there had been no regular check-ups on backup switches to close the flow of  gas in case of any mal functions.  The oil rig was equipped with visual and auditory alarms to shut off gas which was methane,CH4. Unfortunately, since these alarms make too much noise in the early morning  they were deliberately shut off!(Ref.4)

Following the blowout, the oil kept gushing and BP tried to deal with it by the addition of a dispersant called Corexit so the oil could be dispersed over a larger area.(Ref.5) 

Having somewhat understood the way this disaster occurred and the steps taken by BP, let us look at the chemistry of the chemicals present in the oil rigs during the blowout and later the effects on the species living in and around the gulf area. The burning of the oil rig was due to the methane gas, CH4 that was present which is highly inflammable.  The release of such a large amount of methane gas also leads to the depletion of oxygen in the water and the consequent acidification of the water.   This results in the killing of marine life and all other life dependent on it.  In addition, crude oil contains VOCs which are volatile organic compounds like benzene, toluene and xylene.  Benzene is a known human carcinogen, while toluene and xylene cause nausea, vomiting and fatigue to name a few problems that can ultimately lead to long term health hazards like cancer and birth defects.   Crude oil also contains mercury, lead that are known toxins.  Polycyclic hydrocarbons, also known as PAHs are present in crude oil which contains over a hundred different forms of these hydrocarbons.  Again, they are very toxic and cause cancers in mammals and humans.  When crude oil sits on water or shore, its harmful effects can be carried by the wind and air as a toxic aerosol.  When oil coats the body of the animals in the water, including many birds, it limits its ability to feed, move or even reproduce.  It also harms the external and internal organs of the animals adversely.  In addition, the roots of plants and trees along the marshy grasslands near the gulf shore are killed by the presence of oil.  These plants and trees actually protect those coastal regions to a certain extent from strong hurricanes.  Add to that the immense loss in tourism due to oil washing up on the shores of the sandy beaches dotted all over this area.(Ref.6)

To try to counter the presence of oil, as already noted, BP added the dispersant, Corexit.  This may have hidden the presence of oil to observers, but the dispersing only spread it over a larger area.  The excessive amounts used were unprecedented and its effects are well documented 5 years after the spill in a GAP (Government Accountability Project)report.  More than a dozen whistle blowers were interviewed by GAP.  Here is a summary of the first-hand effect of the devastating impacts of the oil in the water and the subsequent Corexit usage.  The witnesses range from cleanup workers, fishermen, scientists, residents and a physician.

1. BP syndrome: all GAP witnesses experienced severe health problems, starting with blood in urine, heart palpitations, skin lesions and skin burning leading to kidney and liver damage and respiratory and nervous system damage.
2. Interviewees were very concerned about long-term results including reproductive damage, endocrine disruption and cancer.
3. Blood test results revealed high levels of chemical exposure to Corexit and oil; the chemicals here are known to be carcinogens.
4. Ecological problems: there is evidence of oil and oil debris even after the cleanup was done.  The oil-Corexit mixture has coated the Gulf seafloor and permeated the rich ecological web leading to barren seafloor, widespread damage to the coral reefs.
5. Majority of fishermen reported that their fish/ sea species had deformities and their catch had decreased substantially after the spill in 2010.(Ref.7)

In conclusion, I have to state that this is a much bigger problem than just BP’s bottom line on profits and gross negligence.  So long as we are dependent on big oil and continue to obtain our energy resources from the fossil fuel industry,we shall go along this slippery slope and destroy our fragile ecosystem and ultimately our lovely planet.

Activities for Middle School Teachers:

VOCs are present in all oil fields.  Students can look at VOCs and its usage in other industries besides oil rigs, e.g., in the paint/ varnish industry.  What safeguards are taken by workers when working with these aromatic compounds?

Students can do simple experiments adding oil to water and seeing how much detergent needs to be added to disperse it. What happens to the oil?  How does a detergent help disperse grease? (Instructor can introduce terms like hydrophilic and hydrophobic here, studying the structures of oil and detergents.) As the ratio of oil to water increases is there a critical point where the detergent is not effective? What other side effects would occur if the detergent is strong like Corexit?

Nuggets of Information:

The Gulf of Mexico has the most methane-rich production area and is also one of the most dangerous places to drill.(Ref.3)

Gas kicks are routine during oil drilling; even blowouts happen a lot of times.  From 1993-1998 there were 11 blowouts, and from 1999-2004 there were 20 blowouts in the Gulf of Mexico!(Ref.3)

Kemp’s Ridley Turtles were ready to be removed from the endangered species list, but thanks to the Deepwater Horizon disaster, they now are facing near extinction.(Ref.8)

Oil kills marshland directly and also poisons the complex mixture of algae, microbes in the soil.(Ref.8)

40% of the Gulf of Mexico’s federal waters were closed to fishing by early June 2010.(Ref.8)

Louisiana is the largest producer of shrimp and oysters in the nation and the second largest producer of crabs.  As a result of this oil rig disaster, the cost to the Louisiana fishing industry could total 2.5 billion dollars.(Ref.9)

A movie about this disaster called “Deepwater Horizon” is set to release soon.(Ref.10)

References:

1.Juhasz,Antonia, Black Tide,p.138 (John Wiley and Sons,2011)

2.deepwaterhorizon.com

3.Juhasz,Antonia, Black Tide,pp.10 ,11(John Wiley and Sons,2011)

4.Juhasz,Antonia, Black Tide,p.24 (John Wiley and Sons,2011)

5.Juhasz,Antonia, Black Tide,p.100 (John Wiley and Sons,2011)

6.Juhasz,Antonia, Black Tide,p.90 (John Wiley and Sons,2011)

7.whistleblower.org/gulftruth

8.Juhasz,Antonia, Black Tide,pp.143-5 (John Wiley and Sons,2011)

9.Juhasz,Antonia, Black Tide,p.163 (John Wiley and Sons,2011)

10.m.imdb.com/title/tt1860357/

Even before visiting the west coast of the United States, many of us have heard of Silicon Valley which is a little south of San Francisco.  This is where the electronics/Computer industry boom occurred.  Why is Silicon attached to the name?   This element, besides being famous for creating glass centuries ago is the 20th and 21st century metalloid used in the semi-conductor industry.

Metalloids are considered to be neither metals nor non-metals.  ( As you already know, metals are willing to give up electrons to become cations, while non-metals are eager to take in electrons to become anions.)  Or they could be considered to be both a metal and a non-metal.  The metalloids are on the right side of the Periodic Table, closer to where the non-metals are positioned.  The metalloids  form a stairs-like configuration and include, Boron, B, silcon, Si, germanium,Ge, arsenic,As, antimony, Sb, tellurium,Te, and polonium, Po.(Ref.1)

These metalloids are usually brittle, shiny and behave like electrical insulators at room temperature.  When heated , they behave like conductors.  They also behave like conductors when small quantities of impurities are introduced or ‘doped’ into the crystalline lattice structure of metals.  Metalloids have the electronic structure in between that of the nearly empty outer shell of typical metals and the nearly filled shells of non-metals.  They have enough empty electronic orbitals into which electrons can be moved to conduct an electric current.  Their chemical properties  are also in between electropositive and electronegative atoms.  In physics one would call these elements semi-conductors.(Ref.2)  Semiconductors  have electrical resistance in between that of a conductor and an insulator. (Ref.3)  The electro negativity and ionization energies of metalloids lie between those of metals and non-metals.(Ref.4)

To understand semi-conductors, let us step back a little to look at the history of radios and transistors.  A radio  is a device that needs electricity and needs to be plugged while a transistor runs on batteries and could be carried around, the’boom box’, as it was called.  The latter relies on semi-conductor technology.  The ‘transistor’ is short for ‘transfer resistance’, and is made up of semiconductors and is a part/component used to regulate the amount of current/voltage  used to amplify/modulate/switch on or off an electronic signal.(Ref. 3)  This is the primary building block for an electronic chip, including the CPO ( central processing unit) in every computer we use.

Let us elaborate.  Silicon changes its behavior to a conductor when small amounts of impurities are added to it.

N-type: small quantities of phosphorus, P, or arsenic, As, are added to pure crystals of Si.  P and As have 5 outermost shell electrons, whereas Si has only 4.  The extra electron is free to move around and causes the silicon to turn into a conductor.( Ref.5)

P- type:when boron,B, or gallium, Ga, is added to Si,these atoms have only 3 electrons in their outermost shell. This results in’holes’or positive charges and once again causes a flow of current in the silicon crystal.   A minute amount or P or N- type doping in silicon causes an insulator into a viable conductor; hence the name semi-conductor.(Ref.5)

One can see that the P or N- type doping, evolved to the P-N-P and N-P-N sandwiches leading to transistors and electronic chips through micro-processors.( See Nuggets)  After the invention of transistors in 1954, the field of electronics has evolved dramatically to where we are now, using smart phones and watches like we always had them, handling all our needs from these devices.  Metalloids have been responsible for these amazing changes in our electronic lives.  Yet there are other significant uses for these metalloids that need to be mentioned as well.  Here are some selected few uses that is by no means complete.

Boron has been used to make high resistance glass, especially to thermal shock, control rods in nuclear reactors, also in strong magnets, in CD and DVD players and MRI machines.  Silicon has been used to make high temperature waxes, alloys of Si have been used to make car parts, also in breast implants and contact lenses.  Germanium has a high refractive index and has been used in wide-angle camera lenses and as a catalyst in polymerization reactions, fiber optics as well as in the treatment of AIDS.  Arsenic as an isotope has been used in locating tumors.  It is also used as an insecticide, fungicide and in the treatment of cancer.  Alloys of antimony have been used to make bullets, in acid batteries. In addition Sb has been used as a catalyst in polymer production.  Tellurium has been used to tint glass, cast in alloys to regulate temperature and making solar cell panels as a semiconductor.  Finally polonium has been used in thermoelectric cells because it releases a large amount of energy.

So these elements in a stair-like formation next to the non-metals in the Periodic Table have made quite a splash in our lives!

Activities for Middle School Teachers:

The first computers were automatic arithmetic engines.(Ref.6)  Logic has something to do with it and George Boole started it all.(See Nuggets)  Students can create and study Truth Tables.  The True or False will correspond to 1 or 0 (zero),switch on or off.  This naturally leads students to review/study binary numbers and compare with the decimal system used in arithmetic.  Instructors could help in letting students see the direct connection between binary numbers and computer arithmetic.

Students can look at the history of the digital age from 1947 onwards.  How do the innovations of say, Apple, social media like Twitter,Facebook etc and on-line ordering services affect our daily lives?  How has it affected small stores using traditional/ old modes of business practices?  Let students compare the seismic shifts in our lives today versus the onset of the printing press or the invention of the telephone.

Nuggets of Information:

John Bardeen, Walter Brattain and William Shockley at Bell Labs developed the transistor on December 23, 1947.(Ref.3)

Transistors replaced vacuum tubes in computers in 1954.(Ref.3)

A diode is the simplest possible semi-conductor device, also called a one- way turnstile for electrons.  The transistor is caused by using three layers of N-P-N or P-N-P sandwich; the transistor could be a switch or an amplifier.  A silicon chip is a piece of silicon with thousands of transistors!(Ref.5)

Boolean logic was developed by George Boole in the mid-1800s.  It allows a few unexpected things to be mapped into bits and bytes ( little pathways of logical information).(Ref.7)

References:

1.http://www.chemicalelements.com/groups/metalloids.html

2.https://www.britannica.com/science/metalloid

3.http://www.computerhope.com/jargon/s/semicond.htm

4.schmoop.com/periodic-table/metals-metalloids.htm

5.electronics.howstuffworks.com.diode/.htm

6.i-programmer.info/babbages-bag/235-logic-ev

7.computerhowstuffworks.com/Boolean.htm