Chemistry Archives - Page 5 of 6 - Eva Varga


May 4, 2013

The first park we visited during our 10-day road trip was Death Valley National Park on the border of California and Nevada in the eastern foothills of the Sierra Mountains.   Death Valley is a land of extremes and we enjoyed the contrasts.  Exploring Death Valley National Park led us to discoveries of Salt Creek pupfish, the mineral borax, and the historical meaning of the 20-mule team.  Today, I share with you a few of our discoveries at Death Vally and describe a fun science experiment you can do with your kids to explore the chemistry of borax. Devils Golf Course

It was evident that despite desolate appearances, Death Valley is one of the most impressive areas for birdwatching in the National Park System. There are several factors that result in Death Valley’s long bird list. As one travels from the low valley desert, up the canyons, through the pinyon-juniper woodlands and onto the high boreal peaks, climate and vegetation changes are obvious. This wide diversity of habitat leads to a high diversity of bird species.

yellow-headed blackbirdOne of our first adventures in Death Valley was the Salt Creek Trail.  It was here that we were able to observe the yellow-headed black bird for the first time.  We were surprised by his lack of timidity for he was only a few feet away from us and hopped about the raised pathway as we took the time to take his photograph.

Another marvel we enjoyed along this trail was the opportunity to observe the endemic Salt Creek pupfish (Cryprinodon salinus salinus). The pupfish of Salt Creek have a difficult life, but it was not always so. Ancestors of the Salt Creek pupfish lived in streams flowing into a huge freshwater lake that filled the bottom of Death Valley more than 10,000 years ago. Lake Manly, as it is known today, was the end of a drainage system that at the time included water from as far west as the Sierra Nevada Mountains. As the climate became more arid over time, the Ice Age lakes and rivers dried up and the pupfish were stranded in permanent water holes scattered across the desert.

Salt Creek pupfishToday, those isolated ‘islands’ of water vary drastically from freshwater warm springs and marshes to Salt Creek’s seasonal briny stream.  To survive in the different habitats, the original pupfish species evolved into ten distinctly different species, each with their own shape, markings, habits, and survival strategies.   Sweetie drew a pupfish in her journal as a part of the Junior Ranger Program.  We mailed our completed books to the park ranger upon our return home, however, as our travel plans did not permit us to return to the visitor center that day.

I like to call these specimens ‘pupfish’ because they play like puppies. ~ Dr. Carl Hubbs, father of Western ichthyology

In addition to the ecology of the valley, early settlers to this region took advantage of the areas rich natural resources. Stories of gold strikes in the newly acquired territory of California had been published in an official notice to Congress in 1848, sparking the California Gold Rush, enticing more than 250,000 people to join the search for riches over the next four years.  Mining continued in Death Valley for 150 years.

20 mule teamCrude shelters and tents once dotted the dry, flat lake bottom. Here, workers refined borax by separating the mineral from unwanted mud and salts, a simple but time-consuming process.  For more than a century, the 20 Mule Team has been the symbol of the borax industry.  The status is well-earned; mule teams helped solve the most difficult task that faced Death Valley borax operators – getting the product to market.  The teams covered 165 miles of forbidding terrain, traveling south through Death Valley, out Wingate Pass, then across the desert to Mojave.

The term  borax is used to refer both to a mineral and to a refined compound. The mineral takes the form of colorless to white soft crystals, which can sometimes have hints of brown, yellow, or green. The substance is also known as sodium tetra-borate and it has been known to humans for thousands of years. The mineral is a chemical compound of the element boron, and the chemical formula is Na2B4O7*10H2O.  A fun activity to try at home is to grow borax crystals in much the same way as you would make rock candy (sugar crystals).  It would also be interesting to research how borax has been used historically and how uses of varied between cultures.

Growing Borax Crystals

Growing borax crystals can teach many different chemical concepts, such as a saturated solution and crystallization.  The basic instructions for growing crystals are show here.  Using this as your control, you may consider varying the solution (what you dissolve the borax into) to see how it affects crystal growth.  Perhaps humidity and ambient temperature play a role in the growth of crystals? 

Materials Needed

  • wide-mouth glass jar
  • a pipe cleaner
  • pencil or chop stick
  • string
  • hot water
  • borax laundry booster

Procedure

As you wait for the water to boil, bend a pipe cleaner into a desired shape (heart, star, circle, etc.).  Then tie a string around your pipe cleaner shape so that you can suspend it in your jar by tying the other end to a pencil or chop stick that will lie across the top of the jar.  Once the water is hot, fill the jar with it, measuring carefully to see how much water you use. For every cup of water, add three tablespoons of borax and stir well until it’s completely, or almost completely, dissolved. Suspend your pipe cleaner and leave overnight. Check it in the morning to see what grew.

Borax is a pretty common household substance and is thereby a great resource for different kinds of science projects. Borax is relatively safe and is very non-reactive, but it is toxic if swallowed, so it should not be used by very young children and it should not be used near food. It also can be irritating to skin and eyes, so you may wish to use regular household gloves when handling it and avoid getting it near your face.



July 19, 20122
Periodic Table of the Elements
Photo by E.Lite

When I was in college, I spent a great deal of time on the campus of the University of Oregon.  While I was not a student here, my boyfriend (now my husband) was and I thereby spent a great deal of time with him in Klamath Hall and the Art Library (he liked the intimacy of this library better than the larger Knight Library).  One of the things I remember most about this part of campus was the visual Periodic Table of Elements.  When we had free time in Eugene recently, I knew this was one venue I wanted to share with my kiddos since we had recently spent some time learning a little chemistry ourselves.

I was delighted to discover that the building was accessible in the summer and open to the public.  Prior to our arrival, my kiddos couldn’t quite understand my desire to show them this when I tried explaining it in words.  Once they saw it in person, however, they were excited and very grateful.  They loved finding their favorite elements:  Au, Po, and Ra.  Can you tell we also read a biography of Marie Curie?

I inquired with thestaff as to the specifics regarding the elements on display but to my surprise, no one seemed to know anything.  If memory serves me correct, however, I believe that one mole of each element is on display. A mole is a chemical mass unit, defined to be 6.022 x 1023 molecules, atoms, or some other unit. The mass of a mole is the gram formula mass of a substance. For example, 1 mole of copper has 6.022 x 1023 atoms and weighs about 63.54 grams.



February 29, 20121

It is Dr Seuss’ birthday later this week (March 2nd) and coincidentally, a local museum has a temporary special exhibit on the artwork of Dr Seuss (see The Art of Dr. Seuss). I figured it was thereby time we celebrated his contributions to children’s literature and art. To prepare for a visit to the museum, we spent the week enjoying a number of his books, most notably;

Silhouettes in honor of Dr SeussI integrated a few other lessons to captivate their imaginations and hopefully, lead us on a few bunny trails.  I love silhouettes and I use them frequently for a number of creative projects – from ATCs, to scrapbook pages, and on occasion to create my own stencils to paint on t-shirts. The Shape of Me & Other Things thereby inspired me to create a profile silhouette of each of the kids.  A friend was staying with us this day … so we have three munchkins pictured.

Predictably, we had to explore the properties of Oobleck upon reading Bartholomew & the Oobleck.  The girls were both familiar with this non-Newtonian fluid.  I was surprised to discover that my little guy was not … an important lesson for me, once again, that I frequently plan our curriculum around Sweetie.  I need to take his experiences to mind as well.

Making Oobleck in honor of Dr Seuss

Today, we’ll read The Boy on Fairfield Street by Kathleen Krull and complete an ‘Artist Biography’ notebook page.  Thereafter, we’ll add Ted Geisel to our ‘Book of Centuries’ and select a favorite art to emulate.  I may even surprise the munchkins Friday morning with green eggs and ham.



January 13, 20121

Young children learn best through hands-on science, or simply “doing.” They learn about the world around them primarily by experiencing it through their senses.

For this reason it is important to focus science lessons around things that they can see, hear, touch, taste, and smell. Late last week, we began a chemistry unit.

I don’t believe I have seen the kids more excited about a subject before. Particularly my daughter who just two days ago checked out four books on specific elements, a fun introductory book on the periodic table, as well as a book of fun experiments. She has already read 3 of them!

Electrolysis of Water

One of the first experiments we undertook enabled us to observe the electrolysis of water; separating the elements in water (hydrogen and oxygen) into their gaseous state.  

The setup was very simple and the kids were ecstatic with what they observed.  We had to look closely, as the bubbles were small, but we indeed could see the accumulation of oxygen gas (O2) and hydrogen gas (‎H2) on the electrodes. Note: we used two pencil lead refills, a polymer carbon, not the element we know of as lead).

As we all know, the chemical formula for water is  ‎H2O. This means there are twice as many hydrogen molecules as oxygen molecules.  When electricity is introduced to water, the molecules split with hydrogen gas (H2) appearing at the cathode.  Since there are more hydrogen molecules than oxygen molecules in water, the electrode that the hydrogen collect upon will have more bubbles.

I asked them to draw their observations in their science journals and their enthusiasm for the subject carried over. Labels, measurements, and careful diagrams were encouraged. I love that they used the chemical symbols for the elements.

Further Exploration

As they are young yet, I didn’t discuss with them the process of reduction or oxidation.  Our focus was simply to understand that by passing a current of electricity through the water, we could separate the atoms of water to get a pure element.  

I have been reading aloud Kathleen Krull’s Marie Curie (Giants of Science). Through much of the book, the author discusses how Marie and her husband Pierre worked tirelessly to isolate radium from a complex compound called Pitchblende.  This simple electrolysis experiment gave the kiddos a small window through which they could understand this process.

For another easy experiment with water, I encourage you to check out Ashley Mullen’s, Walking Water Experiment. Discover the colorful magic of capillary action.

A great book to get kids excited about chemistry is The Periodic Table: Elements with Style! The periodic table shows us the building blocks for every substance in the world. This book is written in a simple and humorous style with great illustrations. It is interesting to me as an adult and simple enough for beginning readers to read independently. 

Science concepts can be introduced early. With each exposure, students will gradually develop a greater understanding of how the world around them works.



October 1, 2011

One of the science labs we did this week provided an opportunity to discover Viscosity.  I started the lesson by asking them if they had ever heard the term before?  I was surprised with Buddy said, “Yeah. I think so.  In Hawai’i I think you talked about it.”  I had completely forgotten this conversation  until he mentioned it.  We had been discussing the speed at which lava flows and I had said that it had a very high viscosity so it was very slow.  The minds of children amaze me.  They remember so much more than we ever give them credit. Anyway …

I wrote the definition down on the white board and asked that they copy it into their journals.  I then showed them the 5 test tubes I had filled with a variety of liquids (tap water, vegetable oil, soap, maple syrup, and ranch dressing) and had allowed to sit on the counter for an hour or so to come to room temperature.  We then carefully dropped a marble into each tube from just above the surface (to minimize any splashing) and timed how quickly it reached the bottom of the tube. 

In most cases, it was relatively quick but there was one surprise … you will have to try this experiment out for yourselves to discover what we had not expected.

We compiled our data and created simple line graphs.  We discussed our results and then I asked the kids, “Do you think heat will change our results?  How do you think heat will affect the speed at which the marble falls to the bottom?”

I allowed time for them to write down their hypothesis and choose one liquid to test … maple syrup, of course.  I thereby filled a sixth test tube with cold syrup from the refrigerator.  The tube with room temperature syrup was placed in a water bath and microwaved it for 30 seconds.  We then repeated the same procedures from before, timing the marble as gravity pulled it through the syrup.

Sweetie predicted, “I think hot maple syrup will have the greatest viscosity because it will have a greater concenthation (concentration).”   Buddy stated, “I think hot syrup will have the most because it is hot.” I tried to get him to elaborate but he got frustrated and exclaimed, “Just because it is is hot.  Why do you need to question me?”

Hot Maple Syrup 1 sec
Room Temperature Syrup  6 sec
Cold Syrup  11 sec
“Heating a liquid decreases it’s viscosity. The marble went through it faster,” explained Sweetie. 
This was a great experiment and they kids had a lot of fun with this one.  I’m sure they’ll want to test other liquids in the future … grape juice, milk, coffee … you name it.  Buddy is already asking, “Will heat make all liquids have less viscosity?”
What I loved most about this experiment is that when we went to our curriculum meeting with our ‘Umbrella Facilitator’ … both kids nailed their explanation of viscosity.  They understood it perfectly!  



October 23, 20101

Astronauts who’ve spent long periods of time in space have found that once back on Earth, they’re weak and may even have a hard time standing up. What’s the trouble?

Vinegar is an acid, a substance that tastes sour and neutralizes bases. In this activity, the vinegar reacts chemically with a substance in the bone called calcium. Calcium is an important mineral in the body that makes bones strong. The vinegar dissolves the calcium in the bones, so the bones are no longer strong and are thereby bendable.

Another way that your bones can lose calcium is through lack of exercise. That’s why some astronauts may come back to Earth with weakened bones and why they now have treadmills and other exercise machines on the International Space Station.