Chemistry Archives - Page 4 of 6 - Eva Varga


November 1, 20141

During the 19th century scientists knew little about what went on inside an atom. However, by the end of the century there were startling new ideas about the structure of the atom resulting from the discoveries of X-rays, radioactivity, and the electron. Marie Curie was amongst the leaders whose discoveries of radioactivity led to a new understanding of atomic structure.

mariecurie

In 1896 Henri Becquerel was using naturally fluorescent minerals to study the properties of x-rays, which had been discovered the previous year by Wilhelm Roentgen. Becquerel exposed potassium uranyl sulfate to sunlight and then placed it on photographic plates wrapped in black paper, believing that the uranium absorbed the sun’s energy and then emitted it as x-rays.

Believing his experiment had failed due to the inclement weather in Paris, he decided to develop his photographic plates anyway. To his surprise, the images were strong and clear, proving that the uranium emitted radiation without an external source of energy such as the sun. Becquerel had discovered radioactivity.

“I am amongst those who think science has great beauty.”

The term radioactivity was actually coined by Marie Curie, who together with her husband Pierre, began investigating the phenomenon recently discovered by Becquerel. The Curies extracted uranium from ore and to their surprise, found that the leftover ore showed more activity than the pure uranium. They concluded that the ore contained other radioactive elements. This led to the discoveries of the elements polonium and radium. It took four more years of processing tons of ore to isolate enough of each element to determine their chemical properties.

Biography

MarieCurie

Maria Sklodowska was born in Warsaw on November 7, 1867, the daughter of a school teacher.  As a young girl, Manya (as she was affectionately called)  received a general education in local schools and some scientific training from her father. She was a brilliant student and dreamed of studying at the Sorbonne in Paris but it took eight years of saving before she could afford to go. Despite very poor living conditions and a lack of French she graduated in physics in 1893 and mathematics in 1894.

“All my life through, the new sights of nature made me rejoice like a child.”

She met Pierre Curie, Professor in the School of Physics in 1894 and in the following year they were married. Her early researches, together with her husband, were often performed under poor laboratory conditions. The discovery of radioactivity by Henri Becquerel in 1896 inspired the Curies in their research which led to the isolation of polonium, named after the country of Marie’s birth.

Pierre was tragically killed in 1906, leaving Marie with two daughters; Irène aged 9 and Eve aged 2. Determined to continue their work, Marie became the first ever woman professor at the Sorbonne and as well as teaching, she discovered how to isolate radium in metallic form. In 1911 she was awarded the Nobel Prize for Chemistry for the discovery of the elements radium and polonium.

“Nothing in life is to be feared, it is only to be understood.”

During World War I, she established a front-line X-ray service in the battlefields of Belgium and France, tirelessly fundraising, training staff, and driving the X-ray vans. After the war, Marie continued her research and to raise funds for a hospital and laboratory devoted to radiology. She eventually died in 1934 from the cumulative effects of radiation exposure.
marie_curie

My daughter is pictured here giving a living history performance as Madame Curie.

Bring it Home

  • Research Marie Curie and her life’s work and create a living history presentation to present to others.
  • Watch the BrainPop video on Marie Curie to learn about her early days, from her humble beginnings in Poland, to her professorship at the Sorbonne.
  • Visit the EPA‘s Radiation Protection Pages to learn about radiation and radiation protection.
  • Write a brief story that describes what Marie Curie might have felt when she realized that she had discovered a new element.

Science Milestones

Visit my Science Milestones page to learn more about scientists whose discoveries and advancements have made a significant difference in our lives or who have advanced our understanding of the world around us.

Explore additional November Birthday lessons and unit studies with iHomeschool Network bloggers.



October 1, 2014

For more than 100 years, the Nobel Prizes have recognized the finest in human achievements, from literature and science to the Nobel Peace Prize, awarded “to the person who shall have done the most or the best work for fraternity between nations, the abolition or reduction of standing armies and for the holding and promotion of peace congresses,” according to the last will and testament of founder Alfred Nobel.

nobel

As we traveled through Scandinavia in 2011, we came upon numerous buildings and monuments that began to unfold the story of the Nobel Prize (like the Oslo City Hall, pictured above, where the Nobel Prize Ceremony takes place).  We also came to discover that the life of Alfred Nobel is a very interesting story.

Biography

Alfred_NobelAlfred Bernhard Nobel was born in Stockholm on 21 October 1833. His father, an inventor and engineer who struggled financially for much of his life, was forced to declare bankruptcy. Immanuel left Sweden and began working in St. Petersburg, Russia, where he impressed the czar with one of his inventions, submerged explosive mines that could thwart a naval invasion. In 1842, when his father was financially stable, Alfred moved with his family to St. Petersburg.

“Success is not a place at which one arrives but rather the spirit with which one undertakes and continues the journey.”

 

Alfred did not attend school but received private tutoring from good teachers. He was quick to master four foreign languages, and showed great ability in the natural sciences, especially chemistry.

Most researchers at the time considered nitroglycerine (discovered by Italian chemist Ascanio Sobrero in 1847) too unsafe to have any practical use. The Nobel family, however, investigated its potential for commercial and industrial uses. Not surprising, their inquiries had tragic results.

“A recluse without books and ink is already in life a dead man.”

 

Seeking a safe way to use the oily liquid, in 1867 Alfred Nobel found that by mixing nitroglycerin with diatomaceous earth, the resulting compound was a stable paste that could be shaped into short sticks that mining companies might use to blast through rock. Nobel patented this invention as “dynamite,” from the Greek word dunamis, or “power.”

The invention of dynamite revolutionized the mining, construction and demolition industries. Railroad companies could now safety blast through mountains, opening up vast stretches of the Earth’s surface to exploration and commerce. As a result, Nobel, who eventually garnered 355 patents on his many inventions, became incredibly wealthy.

When Alfred’s brother Ludvig died in 1888, some journalistic error printed Alfred’s obituary instead. The obituary was widely published and he quickly learned how others perceived him. One French newspaper wrote “Le marchand de la mort est mort,” or “the merchant of death is dead.” The obituary went on to describe Nobel as a man “who became rich by finding ways to kill more people faster than ever before.”

“If I have been of service, if I have glimpsed more of the nature and essence of ultimate good, if I am inspired to reach wider horizons of thought and action, if I am at peace with myself, it has been a successful day.”

Nobel was reportedly stunned by what he read, and as a result became determined to do something to improve his legacy. One year before he died in 1896, Nobel signed his last will and testament, which set aside the majority of his vast estate to establish the five Nobel Prizes, including one awarded for the pursuit of peace.

Not everybody was pleased with this. His will was opposed by his relatives and questioned by authorities in various countries. It took four years for his executors to convince all parties to follow Alfred’s wishes. In 1901, the first Nobel Prizes in Physics, Chemistry, Physiology or Medicine and Literature were first awarded in Stockholm, Sweden and the Peace Prize in Kristiania (now Oslo), Norway.

Bring it Home

On a related note, the Nobel Peace Prize medallion was designed by Norwegian artist Gustav Vigeland. In my post Gustav Vigeland: Artist & Visionary, I share his life story and a complimentary art lesson.

Science Milestones

Visit my Science Milestones page to learn more about scientists whose discoveries and advancements have made a significant difference in our lives or who have advanced our understanding of the world around us.

Explore additional October Birthday lessons and unit studies with iHomeschool Network bloggers.



March 3, 20147

What is your favorite color of Skittles® candy? Do you want to know what dyes were used to make that color? Check out this science project to find out how you can do some scientific detective work to find out for yourself.

Using a simple scientific technique called chromatography, you can separate and identify the various compounds in a complex mixture or solution.

RainbowCandiesIn this activity, water is used as the mobile phase (or solvent), a fluid the solution is dissolved in.  The stationary phase, the material the fluid moves through, is filter paper (a coffee filter cut into strips will work well). The water is absorbed into the fibers of the paper by capillary action.  As the water travels through the paper, it picks up ink particles (the solute) and carries them along. This same process that spoils a perfect print-out can also be put to good use.

The components in the dye mixture move at different speeds as they travel through the stationary phase due to the different properties of the solution’s components, such as their molecular sizeelectrical charge, or other chemical properties. In paper chromatography, different pigments can be separated out from a solution based on the solubility of the pigments. A pigment that is more soluble (or more hydrophilic) than another pigment will generally travel farther because it will be easier for it to dissolve in the mobile phase (water) and be carried along the stationary phase (filter paper). A pigment that is less soluble (or more hydrophobic), or interacts more with the filter paper than the water, will generally travel a shorter distance.

Candy Chromatography

How are the dyes used in hard-shelled candies similar? How are they different?

Materials

  • Candies with a colored coating ~ I recommend testing four different colors and five identical candies of each color
  • Filter paper ~ I used a white coffee filter cut into rectangles of approx. 1″ x 3″
  • Petri dish (or small plate)
  • Pipet or eyedropper
  • Cup of water
  • Skewer or chopstick
  • Tape

Procedure

  1. Prepare the test strips by making a faint line on each strip with a pencil about 1″ from the bottom of the strip.
  2. Tape the other end to the skewer so that the strip hangs freely.
  3. Place the candies in a shallow dish and add a few drops of water atop each candy.  In a few moments a small colored puddle should form.
  4. With the pipet, place a drop of the colored candy solution onto the line you drew on the test strip.
  5. Carefully place the strip into the cup containing the water.  The pencil mark should NOT be in the solution but rather be about 1/2 inch above the water.  Make sure, though, that the end of the paper is in the water.  Watch the water as it moves up the strip of paper (due to capillary action), and see what happens as it comes in contact with the candy solution.  Leave the strip in the solution until the dye no longer travels up the strip with the water.
  6.   When this is complete, remove the strip of paper and place it somewhere on your desk so that it can dry thoroughly.  Continue to test the remaining strips.

Integrating Math

Rf Example 1

Why do different compounds travel different distances on the piece of paper?  In paper chromatography, you can see the components separate out on the filter paper and identify the components based on how far they travel. To do this, we calculate the retention factor (Rf value) of each component. The Rf value is the ratio between how far a component travels (the dye) and the distance the solvent (the water) travels from a common starting point (the origin).  To calculate the Rf value, divide the distance traveled by the sample component by the distance traveled by the solvent. For example, 2.5cm ÷ 5.0cm = 0.5

You can use Rf values to identify different components as long as the solvent, temperature, pH, and type of paper remain the same. This ratio will be different for each component due to its unique properties, primarily based on its adhesive and cohesive factors.

Take it Further

  • Try this project with a variety of candies— for example, does the red in Skittles® look the same as the red in M&Ms® when processed with chromatography? Is the average Rf value nearly the same? Look in the ingredients on each package – were the same dyes used?
  • Try this experiment again but this time use different kinds of solvents (e.g., salt water, vegetable oil, isopropyl rubbing alcohol, etc.). Does a dye travel different distances depending on the solvent you use? What do you think this tells you about the solubility of that dye in the different solvents?
  • Do the dyes you tested travel differently on different kinds of filter paper (lightweight paper towels, heavyweight paper towels, white coffee filter papers, etc.)?

You can probably now imagine how chromatography can be used to separate specific components from a complex mixture and identify chemicals, for example crime scene samples like blood, drugs, or explosive residue. Highly accurate chromatographic methods are used for process monitoring, for example to ensure that a pharmaceutical manufacturing process is producing the desired drug compound in pure form.



March 1, 20145

The Bunsen Burner, is a common piece of laboratory equipment that produces a single open gas flame used for heating, sterilization, and combustion was invented by German chemist Robert Wilhelm Eberhard von Bunsen on March 31, 1811. Working alongside his lab assistant, Peter Desaga, he designed a burner with a hot, sootless, non-luminous flame by mixing the gas with air in a controlled fashion before combustion. Bunsen burners are now used in laboratories all around the world. The device in use today safely burns a continuous stream of a flammable gas such as natural gas (generally methane) or a liquefied petroleum gas such as propane, butane, or a mixture of both.

bunsen burner

Subscribers to my newsletter will receive the download link to my Burning Sugar Lab (pictured above).

Biography

Robert BunsenRobert Wilhelm Eberhard von Bunsen was born on March 30, 1811 at Göttingen in 1811, in what is now the state of Lower Saxony in Germany (though there are some documents stating the 31st). Bunsen was the youngest of four sons of the University’s chief librarian and professor of modern philology, Christian Bunsen. He investigated emission spectra of heated elements, and discovered caesium (in 1860) and rubidium (in 1861) with Gustav Kirchhoff. He also developed several gas-analytical methods, was a pioneer in photochemistry, and did early work in the field of organoarsenic chemistry.

Bunsen was one of the most universally admired scientists of his generation. A master teacher, he always conducted himself as a perfect gentleman, maintaining his distance from theoretical disputes. He much preferred to work quietly in his laboratory, continuing to enrich his science with useful discoveries. As a matter of principle he never took out a patent. He retired at the age of 78 and thereafter pursued his interests in geology and mineralogy. He died in Heidelberg at the age of 88.

Bring it Home

Upon reading about Eberhard von Bunsen and his invention, I really wanted an opportunity for my kiddos to experience using a Bunsen burner. However, as you can guess, a Bunsen Burner is not typically available to homeschool families unless you have access to a high school or college science lab. If this is a possibility for you and you are interested in learning how to use one safely, the video Introduction to the Bunsen Burner provides a great introduction. It also discusses typical lab applications and safety precautions.

As an alternative, there are many hands-on lab activities that can be done safely in your home with simply a candle or Sterno Cooking Fuels. Here are a few ideas that you may wish to explore at home.

    • Burning Sugar Lab – Observe the chemical changes that take place when sugar is exposed to heat
      Subscribers to my newsletter will receive the download link to my Burning Sugar Lab (pictured above)
    • Flame Photometry – Discovering the Emission Spectrum
    • Observe a Candle
      • What happens to the candle when you light it?
      • Can you prove that the candle needs oxygen in order to burn?
      • Can you prove that the candle produces carbon dioxide when it burns?
      • What happens when you hold a piece of glass in different parts of the flame? What do these results say about the process of burning wax in a candle?
      • Is it possible to light a candle without touching the flame directly to the wick? Why or why not?
      • Sketch and label the flame. What part of the flame is the hottest?
      • Design an inquiry experiment to compare different brands of commercial candles?

Science Milestones

Visit my Science Milestones page to learn more about scientists whose discoveries and advancements have made a significant difference in our lives or who have advanced our understanding of the world around us.

To find out about more people born in March hop on over to iHomeschool Network’s March birthdays page.



October 19, 20134

It has been a great week!  We have managed to squeeze in so much learning that it’s hard to believe we have also had quality time with friends and family.  Our endeavors and opportunities this week provided us with a greater understanding of the moon’s phases as we began a year-long moon journal project.  In addition, we explored chemical changes and solubility with ultraviolet light.

sun prints

Sun Prints

My girlfriend brought over a package of large sun print paper so we took advantage of the beautiful day to sneak in a little science.  Sun Prints were originally developed by the Lawrence Hall of Science in 1975 and have been popular in art and science classrooms ever since.  The magic behind this classic activity involves a little chemistry – specifically chemical changes and water solubility.

In the presence of ultra-violet light, two molecules embedded in the paper interact to form a new molecule. Their interaction is initiated by the specific wavelengths of ultra-violet light. The new molecule is colorless so that as the blue molecules are converted, the white of the paper base begins to show through. As the chemical reaction takes place, the areas of the paper exposed to the sun will fade from blue to white.

Areas of the paper covered by objects still contain the original blue molecule, so they remain blue.  According to package directions, when you see most of the color disappear from the paper,  the print has been fully exposed and you are to put the paper into water. This does two things …

First, the original blue compound is water soluble, thus when you immerse it in the water, the blue compound is carried away, leaving only the white paper base. Second, the new colorless compound is not water soluble, and therefore does not wash away. However, water stimulates another chemical change … an oxidation reaction that turns the colorless compound into the deep blue of a finished sun print.

The result is a cool piece of art.  I love that Sweetie did organic items (leaves, seeds, shells, a bird skull, etc.) whereas Buddy used his new Boeing 747 model.

moon jounals

Moon Journals

As we got underway with the World MOON Project earlier this month, the kids have been joyfully pointing the moon out every night. To be honest, it took us a few weeks to get into the habit, but now they delightedly point it out.

Presently, they are recording their observations on a simple sheet I printed out from the curriculum, but as we sat down this week for the first descriptive writing assignment (an essay requirement for the project), they both stated they’d like a special nature journal for the moon. “I’d like to put a poem I wrote about the moon in it and do some special art projects about the moon,” Sweetie exclaimed.

I have been wanting to start year-long moon journals for a long time.  They didn’t have to twist my arm. We will be purchasing a new journal this weekend.  In fact, I have the perfect art project already in mind. You can see some of my moon journal ideas pinned on my Nature Study & Journaling board.

Extras

  • We prepared three of our favorite meals this week – it was all about comfort food: corned beef and cabbage, meatloaf, and meat biscuits.
  • I made homemade vegetable broth with the left over veggie scraps.
  • The kids performed well as their fall recital.
  • Even better, my mom (Grandma R) was able to drive down to see the recital.
  • Mom taught me how to can tuna!!
Homegrown Learners


July 16, 20132

In this activity, you will use a procedure that is similar to flame photometry to observe the color of light produced when various chemical compounds are burned. You’ll need an adult to help you with this experiment, and you will have to perform the experiment extremely carefully so that the flames stay small and under control. What colors will different chemicals produce?

flame photometry

Materials

  • Boric acid
  • Copper sulfate
  • Strontium chloride
  • Sodium chloride (table salt)
  • 2 glasses of water
  • wooden skewers
  • Clean Burning Fuel Tablets
These chemicals are available in small quantities for purchase from Home Science Tools

Experiment

  1. Dip the skewer in water.
  2. Dip the wet skewer into the boric acid.
  3. Dim the lights and place the boric acid-covered skewer into a flame. What color does the flame produce?
  4. Extinguish flame by placing skewer into another glass of water.
  5. Dip another skewer in water.
  6. Dip the wet skewer into the sodium chloride (table salt).
  7. Again, dim the lights and place the sodium chloride-covered skewer into a flame. What color does the tartar flame produce?
  8. Extinguish flame by placing skewer into another glass of water.
  9. Repeat with the remaining chemicals, testing them one at time.

When you are sure everything has been extinguished, you can dispose of the used chemical coated skewers and spent fuel tablet in the garbage. What colors were produced as each chemical burned? Sodium chloride (table salt) and strontium chloride both have a chloride ion, but have a different metal ion (sodium vs. strontium). Are the flame colors produced by these two compounds similar or different? What does this tell you about the source of the color?

Explanation

The experiment that you just conducted is called a flame test.  Flame photometry is a procedure used  to detect certain elements in a material. When you put the boric acid in the flame, you should have notice a bright green flame. The green flame denotes the presence of the element Boron. The cream of tartar should have yielded a purple flame, the color associated with the presence of potassium (cream of tartar is a potassium salt). These element-specific colors are a result of their emission spectrum. The emission spectrum of an element is the color emitted when an atom’s electrons make a transition from a high energy state to a low energy state.

Questions to Ponder

  • How are the colors produced by a chemical when it burns related to the atomic structure of the chemical?
  • What is flame spectrometry and how is it used by physicists and chemists?
  • How does this activity relate to what astronomers do when they are trying to identify the atomic makeup of a star?
  • What are metal ions? In the chemicals used in this science project which elements in the compounds are metals?