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Lead is a dense element
Lead is a dense element
Lead is a very abundant metal noted for it's high density and ability to bend. Because of its density and availability, lead has been added to countless products over human history. Lead has been used in piping, gasoline, paint, and ammunition among other applications.
The health implications for lead use have been known for centuries, but it was only recently banned in the US. Lead is a known neurotoxin with severe impacts on brain health.
Lead has a density of 11,340 kg/m³
Lead has a density of 11,340 kg/m³
Lead is nearly twice as dense as iron, but not as dense as Platinum, Iridium, or Osmium.
Lead is also very atomically stable. All atoms decompose, but some breakdown faster than others. Because of this, the total amount of lead in the universe is slowly increasing as most heavier atoms (all of which are unstable) gradually decay to lead.
The abundance of lead in the Solar System since its formation 4.5 billion years ago has increased by about 0.75%.
Despite its relatively high atomic number, Pb is more prevalent than most other elements with atomic numbers greater than 40.
The concentration of Pb in continental crust is significant compared to many other elements.
The concentration of Pb in continental crust is significant compared to many other elements.
Elemental Number vs Abundance in Continental Crust
The Pb symbol for lead stands for "plumbum". The english word for "plumbing" is derived from this word.
The Pb symbol for lead stands for "plumbum". The english word for "plumbing" is derived from this word.
Because lead is readily available and easy to bend, it has been used in piping for thousands of years. The romans used so much lead piping in their water system, their term for lead was adopted to become the term for "waterworks" as well as the professions associated with those works.
There is evidence that ancient human societies have been using lead for thousands and thousands of years...
There is evidence that ancient human societies have been using lead for thousands and thousands of years...
...and have known about its dangers for nearly as long. Some may consider the usage of lead to be pretty "dense".
...and have known about its dangers for nearly as long. Some may consider the usage of lead to be pretty "dense".
Saturn Devouring His Son is one of Goya's most famous paintings (1820) about the Roman god.
The Ancient Romans knew about the dangers of Pb
The Ancient Romans knew about the dangers of Pb
The health implications of lead were known to the Romans. There are numerous cases of documented lead poisoning in ancient Rome. Some scholars have argued that one of the causes of Rome's downfall was the extensive lead plumbing system causing mental decline amongst the aristocracy. An article in the EPA Journal noted these ancient medical concerns:
"The ancients regarded lead as the father of all metals, but the deity they associated with the substance was Saturn, the ghoulish titan who devoured his own young. The very word ‘saturnine,’ in its most specific meaning, applies to an individual whose temperament has become uniformly gloomy, cynical, and taciturn as the results of lead intoxication." (Lewis, 1985.)
Saturn, the roman god of lead, is known as Kronos in Greek mythology. He is the father of many other important deities, including Zeus, Hera and Hades. He is also known as "father time".
The Ancient Greeks knew about the dangers of Pb
The Ancient Greeks knew about the dangers of Pb
Most of the Roman gods were analogous to their Greek contemporaries, in large part because they shared a lot of the same scientific knowledge and culture. In the same way, the dangers of lead were well known to many scientists in ancient Greece. The Greek poet and physician Nikandros of Kolophon wrote about lead poisoning in his work Alexipharmaka:
“In second place consider the hateful brew compounded with gleaming, deadly white lead whose fresh color is like milk which foams all over when you milk it rich in the springtime into the deep pails. Over the victim’s jaws and in the grooves of the gums is plastered an astringent froth, and the furrow of the tongue turns rough on either side, and the depth of the throat grows somewhat dry, and from the pernicious venom follows a dry retching and hawking, for this affliction is severe; meanwhile his spirit sickens and he is worn out with mortal suffering. His body too grows chill, while sometimes his eyes behold strange illusions or else he drowses, nor can he stir his limbs as heretofore, and he succumbs to the overwhelming fatigue.”
Lead Carbonate: 2PbCO3·Pb(OH)2
The Ancient Chinese knew about the dangers of Pb
The Ancient Chinese knew about the dangers of Pb
According to some sources, lead was used in the Ancient Chinese royal court as a stimulant, as currency, and as a contraceptive. Lead carbonate (pictured here) was used as a cosmetic to bleach skin and was noted for its satin feel.
Chinese medical texts dating back to the Song Dynasty (1000 BC) and the Ming Dynasty (fourteenth to seventeenth century) mention lung ailments related to rock crushing and symptoms of occupational lead poisoning were recognized. The Tang Dynasty alchemist Chen Shao-Wei stated that lead, silver, copper, antimony, gold, and iron were poisonous.
Various civilizations of the Fertile Crescent used lead as a writing material, as currency, and as a construction material.
The Ancient Egyptians didn't know about the dangers of Pb
The Ancient Egyptians didn't know about the dangers of Pb
The Ancient Egyptians were the first to use lead minerals in cosmetics, an application that spread to the other ancient societies mentioned above. The Egyptians used lead for sinkers in fishing nets, glazes, glasses, enamels, and for ornaments.
The Egyptian medical treatise, the Ebers Papyrus, even calls for powdered lead to treat eye problems. No medical texts from that time period indicate that the Egyptians were aware of the dangers of lead.
Don't I use lead in my pencil? Is that stuff dangerous?
Don't I use lead in my pencil? Is that stuff dangerous?
The Roman stylus was made of a large chunk of [Pb]
The ancient Romans used a writing device called a stylus. This was similar to the modern stylus used with smartphones and tablets, except it was bigger and made from lead. Instead of inputting data electronically, the Roman stylus was used to etch markings into wax tablets or to leave dark marks on papyrus, a plant-based substance that was used the way we use paper today. (Bennett, 2022)
In the 16th century, a large deposit of pure, solid graphite was discovered in Borrowdale, England. This was the first time in recorded history that high quality, solid graphite had been found. When metallurgists first encountered this substance, they thought it was some sort of black lead, rather than a form of carbon. Thus, they called it “plumbago”, which is derived from “plumbum”, which is Latin for “lead”. (Hiskey, 2010)
While "lead" pencils are named after the Roman stylus, they have always used graphite [C], never [Pb]
What causes lead toxicity?
What causes lead toxicity?
Lead acts on many biological compounds, damaging lipid production (membranes), impairing heme biosynthesis (an important component of blood), and destroying mitochondria. The physiological symptoms that manifest from lead toxicity effect nearly every part of the body. Increased exposure to lead can lead to many of these problems.
Even with thousands of years of medical concerns, lead was added to paint in the US up until 1978.
Even with thousands of years of medical concerns, lead was added to paint in the US up until 1978.
For the same reasons that the Ancient Egyptian scribes used lead in their calligraphy, lead was added to paint to accelerate the drying time. Lead also gave paint a slightly different color and was praised for it's sheen and finish. Houses painted before the ban date may be hazardous; if a child eats leaded paint chips, you should call poison control ASAP!
Despite the ban on leaded paint in the US, lead added to gasoline was not banned until much later.
Despite the ban on leaded paint in the US, lead added to gasoline was not banned until much later.
Tetryethyl lead was added to gas to reduce engine knocking, boost octane ratings, and to help with wear and tear on valves in the engine. While the addition of heavy lead did improve performance to a slight degree, the lead fumes were considered highly toxic and were finally banned by the EPA on January 1, 1996.
One scientist led the lead takedown
One scientist led the lead takedown
Clair Patterson was a premier geochemist that worked with George Tilton to transform uranium-lead dating into lead-lead dating. By comparing the lead from the Canyon Diablo meteorite to that found in the earth, he was able to calculate the age of our planet at approximate 4.55 billion years old. Other data from astronomy and geophysics have confirmed this number which has not changed much from his original 1956 calculation.
In his work with dating, Clair noticed patterns of irregularity that indicated that lead additives to fuel were contaminating all of his samples on Earth. This lead him to further research and discoveries about the impact of lead to soil, water, air and the food chain. He crusaded against lead additives for the rest of his career, ultimately helping to ban the addition of lead to fuel and the use of lead solder in food cans.
The scientist that led lead dating (with the formulas above) helped lead become dated
Lead isn't completely banned, and still has some important uses.
Lead isn't completely banned, and still has some important uses.
Solder (saw-der) is a combination of metal elements that melts at a desired temperature and can help conduct electricity by bridging a circuit. Some solder enthusiasts swear by Pb and will actively avoid lead-free solder.
Lead acid batteries were the first rechargeable battery ever designed, and are still used in a majority of our on-road vehicles to power the starter.
Sn60/Pb40 is an industry standard solder blend. Prop 65 warnings alert Californians to the potential carcinogen dangers of lead solder.
The "smoke" you see from solder is actually rosin, a different chemical that helps solder flow. You should still be wary of lead fumes when using a soldering iron.
Disposal of PbO2 batteries from cars must be taken with great care because of both the corrosive sulfuric acid and the toxicity of lead.
Leaded pipes are still in use in many places across the country. When those pipes start to leech lead into the water supply, big problems arise.
Leaded pipes are still in use in many places across the country. When those pipes start to leech lead into the water supply, big problems arise.
Flint, Michigan switched their water source without changing all of the old lead pipes in their community. The new water wasn't correctly treated for the aging lead pipes and caused rapid corrosion and lead leakage into the drinking water. The socioeconomic and racial issues within the area have have been tangled up in this health crisis.
The Flint Water Crisis was a result of high Pb levels in the drinking water in the areas surrounding Detroit. The water was noticeably yellow (a result of the Pb) and poisonous for consumption. Levels of lead above 15 ppb (parts per billion) warrant a federal response; Flint levels reached as high as 100 ppb and provoked a massive social movement to fix the issue.
Thanks to advocates, the Flint water Pb-levels have decreased significantly. Hopefully these levels continue to decline, assuming no one makes the "dense" decisions to use lead plumbing again.
Lead OC (15 pts)
Lead OC (15 pts)
Lead is one of the most dense elements. Calculate some densities of objects and compare those values to the density of lead (11,340 kg/m^3)
(5 pts) Document the mass and volume of an object with pictures. Upload those pictures to a shared Google Drive folder.
(5 pts) Document the mass and volume of an object with pictures. Upload those pictures to a shared Google Drive folder.
Determining the volume of your object might be difficult if you select a challenging shape. Try to find something with easy geometric approximations (like a rectangular prism or a cylinder).
1 pt for the mass measurement picture, 3 pt for the volume measurement pictures (1 per dimension), 1 pt for the shared folder on Drive
(3 pts) Determine the volume of your object.
(3 pts) Determine the volume of your object.
EASY (Geometric approximation with 1 single shape): Calculator
INTERMEDIATE (Geometric approximation with 2+ shapes): Water Bottle
HARD (No geometric approximation, displacement method): Fork
Mass: 60.8g
Width: 6.7 cm
Length: 11.5 cm
Height: 1.2 cm
V = l*w*h
V = l*w*h
V = (6.7 cm)*(11.5 cm)*(1.2 cm)
V = 92 cm^3
V = 92 mL
Mass: 260.2g
Diameter Bottom: 6.3 cm
Radius Bottom: 3.2 cm
Diameter Top: 2.6 cm
Radius Top: 1.3 cm
Base Cylinder Height: 6.6 cm
Cone Height: 3.5 cm
Head Cylinder Height: 1.6 cm
V = Base Cylinder + Cone + Head Cylinder
V = (pi)(r^2)(h) + 1/3(pi)(r^2)(h) + (pi)(r^2)(h)
V = π(3.2 cm)²(6.6 cm) + ⅓π(3.2 cm)²(3.5 cm) + π(1.3 cm)²(1.6 cm)
V = pi*3.2^2*6.6+1/3*pi*3.2^2*3.5+pi*1.3^2*1.6
V = 258.3 cm^3 / 253 mL
Mass: 23.2g
Original water level: 97 mL
Final water level: 100 mL
Displacement: 3 mL
(3 points) Use Google Trends to identify the popularity of other social movements.
(3 points) Use Google Trends to identify the popularity of other social movements.
Google Trends can show the popularity of certain search terms based on their search queries throughout Google's history. Identify a social movement (example: "BLM") and use Google Trends to identify when the movement picked up pace. Can you identify some future social movements based on your Trends?
The BLM social movement is a relatively recent phenomenon. Searches from 2004 to 2015 had minor spikes, most likely from the other popular "BLM" search, the Bureau of Land Management. A scan of news articles from April 2014 (a spike on the graph) shows a cattle rancher dispute with the Bureau.
The biggest spike in search interest occurred in June 2020. The push to celebrate Black History with the introduction of Juneteenth as a national holiday may have sparked this historical peak in that particular month.
(2 points) Use Google Trends to compare 2 different topics or trends.
(2 points) Use Google Trends to compare 2 different topics or trends.
Include a picture of your competing search terms and a brief description of the results.
Over the last 5 years, "Drake" has more interest on average, but that could be because of the ubiquitous nature of the word. Peaks are likely because of album drops or news stories (Kanye's presidential candidacy, Kendrick's Grammy, etc). Overall, Drake and Kanye seem more popular than Kendrick.
"Fortnite is dead." Since October 2019, the popular game has drawn less interest and fewer search queries. After 2 years (10/21), the interest for "Fortnite" is less than 20% of the peak traffic. Was it Valorant or Apex that killed Fortnite? From the data, it looks like neither game actually garnered that much search traffic on their own; Fortnite seemed to burn out on its own.
CHEMISTRY B SEMESTER ONLY
Pb v1.1
Pb v1.1
Show your usage of Pb in the Soldering Lab. Include a video of you soldering (1 pt), a diagram of your circuit (4 points), a picture of your completed solder job (2), evidence of LEDs producing light (3).
Student Example
Student Example
Student Example
Student Example
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